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10,600 | Positive UTC offsets describe a time zone at or east of , where the civil time is the same as or ahead (or later) than UTC so the zone designator will look like "+02:00","+0200", or "+02". | https://en.wikipedia.org/wiki?curid=15024 |
10,601 | To represent a negative offset, ISO 8601 specifies using a minus sign, (). If the interchange character set is limited and does not have a minus sign character, then the hyphen-minus should be used, (). ASCII does not have a minus sign, so its hyphen-minus character (code is 45 decimal or 2D hexadecimal) would be used. If the character set has a minus sign, then that character should be used. Unicode has a minus sign, and its character code is U+2212 (2212 hexadecimal); the HTML character entity invocation is codice_1. | https://en.wikipedia.org/wiki?curid=15024 |
10,602 | The following times all refer to the same moment: "18:30Z", "22:30+04", "1130−0700", and "15:00−03:30". Nautical time zone letters are not used with the exception of Z. To calculate UTC time one has to subtract the offset from the local time, e.g. for "15:00−03:30" do 15:00 − (−03:30) to get 18:30 UTC. | https://en.wikipedia.org/wiki?curid=15024 |
10,603 | An offset of zero, in addition to having the special representation "Z", can also be stated numerically as "+00:00", "+0000", or "+00". However, it is not permitted to state it numerically with a negative sign, as "−00:00", "−0000", or "−00". The section dictating sign usage states that a plus sign must be used for a positive or zero value, and a minus sign for a negative value. Contrary to this rule, RFC 3339, which is otherwise a profile of ISO 8601, permits the use of "-00", with the same denotation as "+00" but a differing connotation. | https://en.wikipedia.org/wiki?curid=15024 |
10,604 | A single point in time can be represented by concatenating a complete date expression, the letter ""T"" as a delimiter, and a valid time expression. For example, . In ISO 8601:2004 it was permitted to omit the ""T"" character by mutual agreement as in , but this provision was removed in ISO 8601-1:2019. | https://en.wikipedia.org/wiki?curid=15024 |
10,605 | Separating date and time parts with other characters such as space is not allowed in ISO 8601, but allowed in its profile RFC 3339. | https://en.wikipedia.org/wiki?curid=15024 |
10,606 | Either basic or extended formats may be used, but both date and time must use the same format. The date expression may be calendar, week, or ordinal, and must use a complete representation. The time may be represented using a specified reduced precision format. | https://en.wikipedia.org/wiki?curid=15024 |
10,607 | Durations define the amount of intervening time in a time interval and are represented by the format P[n]Y[n]M[n]DT[n]H[n]M[n]S or P[n]W as shown on the aside. In these representations, the [n] is replaced by the value for each of the date and time elements that follow the [n]. Leading zeros are not required, but the maximum number of digits for each element should be agreed to by the communicating parties. The capital letters "P", "Y", "M", "W", "D", "T", "H", "M", and "S" are designators for each of the date and time elements and are not replaced. | https://en.wikipedia.org/wiki?curid=15024 |
10,608 | For example, "P3Y6M4DT12H30M5S" represents a duration of "three years, six months, four days, twelve hours, thirty minutes, and five seconds". | https://en.wikipedia.org/wiki?curid=15024 |
10,609 | Date and time elements including their designator may be omitted if their value is zero, and lower-order elements may also be omitted for reduced precision. For example, "P23DT23H" and "P4Y" are both acceptable duration representations. However, at least one element must be present, thus "P" is not a valid representation for a duration of 0 seconds. "PT0S" or "P0D", however, are both valid and represent the same duration. | https://en.wikipedia.org/wiki?curid=15024 |
10,610 | To resolve ambiguity, "P1M" is a one-month duration and "PT1M" is a one-minute duration (note the time designator, T, that precedes the time value). The smallest value used may also have a decimal fraction, as in "P0.5Y" to indicate half a year. This decimal fraction may be specified with either a comma or a full stop, as in "P0,5Y" or "P0.5Y". The standard does not prohibit date and time values in a duration representation from exceeding their "carry over points" except as noted below. Thus, "PT36H" could be used as well as "P1DT12H" for representing the same duration. But keep in mind that "PT36H" is not the same as "P1DT12H" when switching from or to Daylight saving time. | https://en.wikipedia.org/wiki?curid=15024 |
10,611 | Alternatively, a format for duration based on combined date and time representations may be used by agreement between the communicating parties either in the basic format PYYYYMMDDThhmmss or in the extended format . For example, the first duration shown above would be . However, individual date and time values cannot exceed their moduli (e.g. a value of 13 for the month or 25 for the hour would not be permissible). | https://en.wikipedia.org/wiki?curid=15024 |
10,612 | The standard describes a duration as part of time intervals, which are discussed in the next section. The duration format on its own is ambiguous regarding the total number of days in a calendar year and calendar month. The number of seconds in a calendar day is also ambiguous because of leap seconds. For example "P1M" on its own could be 28, 29, 30, or 31 days. There is no ambiguity when used in a time interval. Using example "P2M" duration of two calendar months: | https://en.wikipedia.org/wiki?curid=15024 |
10,613 | The duration format (or a subset thereof) is widely used independent of time intervals, as with the Java 8 Duration class which supports a subset of the duration format. | https://en.wikipedia.org/wiki?curid=15024 |
10,614 | A time interval is the intervening time between two time points. The amount of intervening time is expressed by a duration (as described in the previous section). The two time points (start and end) are expressed by either a combined date and time representation or just a date representation. | https://en.wikipedia.org/wiki?curid=15024 |
10,615 | Of these, the first three require two values separated by an "interval designator" which is usually a solidus (more commonly referred to as a forward slash "/"). Section 3.2.6 of ISO 8601-1:2019 notes that "A solidus may be replaced by a double hyphen ["--"] by mutual agreement of the communicating partners", and previous versions used notations like "2000--2002". Use of a double hyphen instead of a solidus allows inclusion in computer filenames; in common operating systems, a solidus is a reserved character and is not allowed in a filename. | https://en.wikipedia.org/wiki?curid=15024 |
10,616 | For <start>/<end> expressions, if any elements are missing from the end value, they are assumed to be the same as for the start value including the time zone. This feature of the standard allows for concise representations of time intervals. For example, the date of a two-hour meeting including the start and finish times could be simply shown as "2007-12-14T13:30/15:30", where "/15:30" implies "/2007-12-14T15:30" (the same date as the start), or the beginning and end dates of a monthly billing period as "2008-02-15/03-14", where "/03-14" implies "/2008-03-14" (the same year as the start). | https://en.wikipedia.org/wiki?curid=15024 |
10,617 | If greater precision is desirable to represent the time interval, then more time elements can be added to the representation. An interval denoted can start at any time on and end at any time on , whereas includes the start and end times. | https://en.wikipedia.org/wiki?curid=15024 |
10,618 | Repeating intervals are specified in clause "4.5 Recurring time interval". They are formed by adding "R[n]/" to the beginning of an interval expression, where "R" is used as the letter itself and [n] is replaced by the number of repetitions. Leaving out the value for [n] or specifying a value of -1, means an unbounded number of repetitions. A value of 0 for [n] means the interval is not repeated. | https://en.wikipedia.org/wiki?curid=15024 |
10,619 | If the interval specifies the start (forms 1 and 2 above), then this is the start of the repeating interval. If the interval specifies the end but not the start (form 3 above), then this is the end of the repeating interval. For example, to repeat the interval of "P1Y2M10DT2H30M" five times starting at , use . | https://en.wikipedia.org/wiki?curid=15024 |
10,620 | ISO 8601:2000 allowed truncation (by agreement), where leading components of a date or time are omitted. Notably, this allowed two-digit years to be used and the ambiguous formats YY-MM-DD and YYMMDD. This provision was removed in ISO 8601:2004. | https://en.wikipedia.org/wiki?curid=15024 |
10,621 | Only the first type (specific date in the implied century) omits the leading codice_2 for century. All other formats have one leading codice_2 per omitted century, year, and month. | https://en.wikipedia.org/wiki?curid=15024 |
10,622 | On the Internet, the World Wide Web Consortium (W3C) uses the IETF standard based on ISO 8601 in defining a profile of the standard that restricts the supported date and time formats to reduce the chance of error and the complexity of software. The very simple specification is based on a draft of the <nowiki>RFC 3339</nowiki> mentioned below. | https://en.wikipedia.org/wiki?curid=15024 |
10,623 | ISO 8601 is referenced by several specifications, but the full range of options of ISO 8601 is not always used. For example, the various electronic program guide standards for TV, digital radio, etc. use several forms to describe points in time and durations. The ID3 audio meta-data specification also makes use of a subset of ISO 8601. | https://en.wikipedia.org/wiki?curid=15024 |
10,624 | The ISO 8601 week date, as of 2006, appeared in its basic form on major brand commercial packaging in the United States. Its appearance depended on the particular packaging, canning, or bottling plant more than any particular brand. The format is particularly useful for quality assurance, so that production errors can be readily traced. | https://en.wikipedia.org/wiki?curid=15024 |
10,625 | IETF RFC 3339 defines a profile of ISO 8601 for use in Internet protocols and standards. It explicitly excludes durations and dates before the common era. The more complex formats such as week numbers and ordinal days are not permitted. | https://en.wikipedia.org/wiki?curid=15024 |
10,626 | <nowiki>RFC 3339</nowiki> deviates from ISO 8601 in allowing a zero time zone offset to be specified as "-00:00", which ISO 8601 forbids. <nowiki>RFC 3339</nowiki> intends "-00:00" to carry the connotation that it is not stating a preferred time zone, whereas the conforming "+00:00" or any non-zero offset connotes that the offset being used is preferred. This convention regarding "-00:00" is derived from earlier RFCs, such as RFC 2822 which uses it for timestamps in email headers. <nowiki>RFC 2822</nowiki> made no claim that any part of its timestamp format conforms to ISO 8601, and so was free to use this convention without conflict. | https://en.wikipedia.org/wiki?curid=15024 |
10,627 | Göbekli Tepe (, "Potbelly Hill"; known as "Girê Mirazan" or "Xirabreşkê" in Kurdish) is a Neolithic archaeological site in the Southeastern Anatolia Region of Turkey. Dated to the Pre-Pottery Neolithic, between 9500 and 8000 BCE, the site comprises a number of large circular structures supported by massive stone pillars – the world's oldest known megaliths. Many of these pillars are richly decorated with figurative anthropomorphic details, clothing, and reliefs of wild animals, providing archaeologists rare insights into prehistoric religion and the particular iconography of the period. The -high, tell also includes many smaller rectangular buildings, quarries, and stone-cut cisterns from the Neolithic, as well as some traces of activity from later periods. | https://en.wikipedia.org/wiki?curid=515395 |
10,628 | The site was first used at the dawn of the Southwest Asian Neolithic period, which marked the appearance of the oldest permanent human settlements anywhere in the world. Prehistorians link this Neolithic Revolution to the advent of agriculture, but disagree on whether farming caused people to settle down or vice versa. Göbekli Tepe, a monumental complex built on the top of a rocky mountaintop, with no clear evidence of agricultural cultivation produced to date, has played a prominent role in this debate. The site's original excavator, German archaeologist Klaus Schmidt, described it as the "world's first temple": a sanctuary used by groups of nomadic hunter-gatherers from a wide area, with few or no permanent inhabitants. Other archaeologists have challenged this interpretation, arguing that the evidence for a lack of agriculture and a resident population was far from conclusive. Recent research has also led the current excavators of Göbekli Tepe to revise or abandon many of the conclusions underpinning Schmidt's interpretation. | https://en.wikipedia.org/wiki?curid=515395 |
10,629 | First noted in a survey in 1963, Schmidt recognised the site as prehistoric in 1994 and began excavations there the following year. After his death in 2014, work continued as a joint project of Istanbul University, Şanlıurfa Museum, and the German Archaeological Institute, under the overall direction of Turkish prehistorian Necmi Karul. Göbekli Tepe was designated a UNESCO World Heritage Site in 2018, recognising its outstanding universal value as "one of the first manifestations of human-made monumental architecture". , less than 5% of the site had been excavated. | https://en.wikipedia.org/wiki?curid=515395 |
10,630 | Göbekli Tepe was built and occupied during the Pre-Pottery Neolithic (PPN)—the earliest division of the Neolithic period in Southwest Asia—which is dated to between 9600 and 7000 BCE. Beginning at the end of the last Ice Age, the PPN marks "the beginnings of village life", producing the earliest evidence for permanent human settlements in the world. Archaeologists have long associated the appearance of these settlements with the Neolithic Revolution—the transition from hunting and gathering to agriculture—but disagree on whether the adoption of farming caused people to settle down, or settling down caused people to adopt farming. Despite the name, the Neolithic Revolution in Southwest Asia was "drawn out and locally variable". Elements of village life appeared as early as 10,000 years before the Neolithic in places, and the transition to agriculture took thousands of years, with different paces and trajectories in different regions. The Pre-Pottery Neolithic is divided into two subperiods: the Pre-Pottery Neolithic A, to which the early phases of Göbekli Tepe belong, is dated to between 9600 and 8800 BCE; the Pre-Pottery Neolithic B, to which the late phases of Göbekli Tepe belong, is dated to between 8800 and 7000 BCE. It was preceded by the Epipalaeolithic and succeeded by the Late Neolithic. | https://en.wikipedia.org/wiki?curid=515395 |
10,631 | Evidence indicates that the inhabitants were hunter-gatherers who supplemented their diet with early forms of domesticated cereal and lived in villages for at least part of the year. Tools such as grinding stones and mortar & pestle, found at Göbekli Tepe, were analyzed and suggest considerable cereal processing. Archaeozoological evidence hints at "large-scale hunting of gazelle between midsummer and autumn." | https://en.wikipedia.org/wiki?curid=515395 |
10,632 | PPN villages consisted mainly of clusters of stone or mud brick houses, but sometimes also substantial monuments and large buildings. These include the tower and walls at Tell es-Sultan (Jericho), as well as large, roughly contemporaneous circular buildings at Göbekli Tepe, Nevalı Çori, Çayönü, Wadi Feynan 16, Jerf el-Ahmar, Tell 'Abr 3, and Tepe Asiab. Archaeologists typically associate these structures with communal activities which, together with the communal effort needed to build them, helped to maintain social interactions in PPN communities as they grew in size. | https://en.wikipedia.org/wiki?curid=515395 |
10,633 | The T-shaped pillar tradition seen at Göbekli Tepe is unique to the Urfa region, but is found at the majority of PPN sites there. These include Nevalı Çori, Hamzan Tepe, Karahan Tepe, Harbetsuvan Tepesi, Sefer Tepe, and Taslı Tepe. Other stone stelae—without the characteristic T shape—have been documented at contemporary sites further afield, including Çayönü, Qermez Dere, and Gusir Höyük. | https://en.wikipedia.org/wiki?curid=515395 |
10,634 | Göbekli Tepe is located in the Taş Tepeler ('Stone Hills'), in the foothills of the Taurus Mountains. It overlooks the Harran plain and the headwaters of the Balikh River, a tributary of the Euphrates. The site is a tell (artificial mound) situated on a flat limestone plateau. In the north, the plateau is connected to the neighbouring mountains by a narrow promontory. In all other directions, the ridge descends steeply into slopes and steep cliffs. On top of the ridge there is considerable evidence of human impact, in addition to the construction of the tell. | https://en.wikipedia.org/wiki?curid=515395 |
10,635 | Excavations have taken place at the southern slope of the tell, south, and west of a mulberry that marks an Islamic pilgrimage, but archaeological finds come from the entire plateau. The team has also found many remains of tools. At the western escarpment, a small cave has been discovered in which a small relief depicting a bovid was found. It is the only relief found in this cave. | https://en.wikipedia.org/wiki?curid=515395 |
10,636 | Like most PPN sites in the Urfa region, Göbekli Tepe was built on a high point on the edge of the mountains, giving it both a wide view over the plain beneath, and good visibility from the plain. This location also gave the builders good access to raw material: the soft limestone bedrock from which the complex was built, and the flint to make the tools to work the limestone. | https://en.wikipedia.org/wiki?curid=515395 |
10,637 | At the time when Göbekli Tepe was occupied, the climate of the area was warmer and wetter than it is today. It was surrounded by an open steppe grassland, with abundant wild cereals, including einkorn, wheat, and barley, and herds of grazing animals such as wild sheep, wild goat, gazelle, and equids. Large herds of goitered gazelle may have passed by the site in seasonal migrations. There is no evidence of substantial woodlands nearby; 90% of the charcoal recovered at the site was from pistachio or almond trees. Archaeologists disagree on whether the site provided ready access to drinking water. Schmidt maintained that there was "no access to water in the immediate vicinity", based on the fact that, whilst there are many karstic springs and small streams in the Germuş, the closest today are several kilometres away. However, in the wetter climate of the time, the local water table may have been higher, activating springs closer to the site that are dormant today. Schmidt also noted the presence of several cisterns carved into the bedrock under the site, holding at least of water, and subsequent excavation has uncovered a possible rainwater harvesting system. | https://en.wikipedia.org/wiki?curid=515395 |
10,638 | Radiocarbon dating shows that the earliest exposed structures at Göbekli Tepe were built between 9500 and 9000 BCE, towards the end of the Pre-Pottery Neolithic A (PPNA) period. The site was significantly expanded in the early 9th millennium BCE and remained in use until around 8000 BCE, or perhaps slightly later (the early Pre-Pottery Neolithic B, PPNB). There is evidence that smaller groups returned to live amongst the ruins after the Neolithic structures were abandoned. | https://en.wikipedia.org/wiki?curid=515395 |
10,639 | Schmidt originally dated the site to the PPN based on the types of stone tools found there, considering a PPNA date "most probable". Establishing its absolute chronology took longer due to methodological challenges. Though the first two radiocarbon dates were published in 1998, these and other samples from the of the structure dated to the late 10th and early 9th millennium – 500 to 1000 years later than expected for a PPNA site. Schmidt's team explained the discrepancy in light of their theory that this material was brought to the site from elsewhere when it was abandoned, and so was not representative of the actual use of the structures. They instead turned to a novel method of dating organic material preserved in the plaster on the structure's walls, which resulted in dates more consistent with a PPNA occupation, in the middle or even early 10th-millennium BCE. Subsequent research led to a significant revision of Schmidt's chronology, including the abandonment of the theory that the fill of the structures was brought from elsewhere, and a recognition that direct dates on plaster are affected by the old wood effect. Together with new radiocarbon dates, this has established the site's absolute chronology as falling in the period 9500 to 8000 BCE – the late PPNA and PPNB. | https://en.wikipedia.org/wiki?curid=515395 |
10,640 | Göbekli Tepe follows a geometric pattern. The pattern is an equilateral triangle that connects enclosures A, B, and D. A 2020 study of "Geometry and Architectural Planning at Göbekli Tepe" suggests that enclosures A, B, and D are all one complex, and within this complex there is a "hierarchy" with enclosure D at the top, rejecting the idea that each enclosure was built and functioned individually as less likely. | https://en.wikipedia.org/wiki?curid=515395 |
10,641 | At the western edge of the hill, a lionlike figure was found. In this area, flint and limestone fragments occur more frequently. It was, therefore, suggested that this could have been some kind of sculpture workshop. It is unclear, on the other hand, how to classify three phallic depictions from the surface of the southern plateau. They are near the quarries of classical times, making their dating difficult. | https://en.wikipedia.org/wiki?curid=515395 |
10,642 | Apart from the tell, there is an incised platform with two sockets that could have held pillars and a surrounding flat bench. This platform corresponds to the complexes from Layer III at the tell. Continuing the naming pattern, it is called "complex E". Owing to its similarity to the cult-buildings at Nevalı Çori it has also been called "Temple of the Rock". Its floor has been carefully hewn out of the bedrock and smoothed, reminiscent of the terrazzo floors of the younger complexes at Göbekli Tepe. Immediately northwest of this area are two cistern-like pits that are believed to be part of complex E. One of these pits has a table-high pin as well as a staircase with five steps. | https://en.wikipedia.org/wiki?curid=515395 |
10,643 | At this early stage of the site's history, circular compounds or "temene" first appear. They range from in diameter. Their most notable feature is the presence of T-shaped limestone pillars evenly set within thick interior walls composed of unworked stone. Four such circular structures have been unearthed so far. Geophysical surveys indicate that there are 16 more, enclosing up to eight pillars each, amounting to nearly 200 pillars in all. The slabs were transported from bedrock pits located approximately from the hilltop, with workers using flint points to cut through the limestone bedrock. The pillars are the oldest known megaliths in the world. | https://en.wikipedia.org/wiki?curid=515395 |
10,644 | Two taller pillars stand facing one another at the centre of each circle. Whether the circles were provided with a roof is uncertain. Stone benches designed for sitting are found in the interior. Many of the pillars are decorated with abstract, enigmatic pictograms and carved animal reliefs. The pictograms may represent commonly understood sacred symbols, as known from Neolithic cave paintings elsewhere. The reliefs depict mammals such as lions, bulls, boars, foxes, gazelle, and donkeys; snakes and other reptiles; arthropods such as insects and arachnids; and birds, particularly vultures. At the time the edifice was constructed, the surrounding country was likely to have been forested and capable of sustaining this variety of wildlife, before millennia of human settlement and cultivation led to the near–Dust Bowl conditions prevalent today. Vultures also feature prominently in the iconography of Çatalhöyük and Jericho. | https://en.wikipedia.org/wiki?curid=515395 |
10,645 | Few humanoid figures have appeared in the art at Göbekli Tepe. Some of the T-shaped pillars have human arms carved on their lower half, however, suggesting to site excavator Schmidt that they are intended to represent the bodies of stylized humans (or perhaps deities). Loincloths appear on the lower half of a few pillars. The horizontal stone slab on top is thought by Schmidt to symbolize shoulders, which suggests that the figures were left headless. Whether they were intended to serve as surrogate worshippers, symbolize venerated ancestors, or represent supernatural, anthropomorphic beings is not known. | https://en.wikipedia.org/wiki?curid=515395 |
10,646 | Some of the floors in this, the oldest, layer are made of terrazzo (burnt lime); others are bedrock from which pedestals to hold the large pair of central pillars were carved in high relief. Radiocarbon dating places the construction of these early circles around 9000 BCE. Carbon dating suggests that (for reasons unknown) the enclosures were backfilled during the Stone Age. | https://en.wikipedia.org/wiki?curid=515395 |
10,647 | The creation of the circular enclosures in layer III later gave way to the construction of small rectangular rooms in layer II. Rectangular buildings make more efficient use of space compared with circular structures. They often are associated with the emergence of the Neolithic, but the T-shaped pillars, the main feature of the older enclosures, also are present here, indicating that the buildings of Layer II continued to serve the same function in the culture, presumably as sanctuaries. Layer II is assigned to Pre-Pottery Neolithic B (PPNB). The several adjoining rectangular, doorless, and windowless rooms have floors of polished lime reminiscent of Roman terrazzo floors. Carbon dating has yielded dates between 8800 and 8000 BCE. Several T-pillars up to 1.5 meters tall occupy the center of the rooms. A pair decorated with fierce-looking lions is the rationale for the name "lion pillar building" by which their enclosure is known. | https://en.wikipedia.org/wiki?curid=515395 |
10,648 | A stone pillar resembling totem pole designs was discovered at Göbekli Tepe, Layer II in 2010. It is 1.92 metres high and is superficially reminiscent of the totem poles in North America. The pole features three figures, the uppermost depicting a predator, probably a bear, and below it a human-like shape. Because the statue is damaged, the interpretation is not entirely clear. Fragments of a similar pole also were discovered about 20 years ago in another site in Turkey at Nevalı Çori. Also, an older layer at Göbekli features some related sculptures portraying animals on human heads. | https://en.wikipedia.org/wiki?curid=515395 |
10,649 | Layer I is the uppermost part of the hill. It is the shallowest but accounts for the longest stretch of time. It consists of loose sediments caused by erosion and the virtually-uninterrupted use of the hill for agricultural purposes since it ceased to operate as a ceremonial center. | https://en.wikipedia.org/wiki?curid=515395 |
10,650 | Around the beginning of the 8th millennium BCE, Göbekli Tepe lost its importance. The advent of agriculture and animal husbandry brought new realities to human life in the area, and the "Stone-age zoo" (Schmidt's phrase applied particularly to Layer III, Enclosure D) apparently lost whatever significance it had had for the region's older, foraging communities. However, the complex was not simply abandoned and forgotten to be gradually destroyed by the elements. Instead, each enclosure was deliberately buried under as much as of refuse, creating a tell consisting mainly of small limestone fragments, stone vessels, and stone tools. Many animal and human bones have been identified in the fill. The site was deliberately backfilled sometime after 8000 BCE: the buildings were buried under debris, mostly flint gravel, stone tools, and animal bones. In addition to Byblos points (weapon heads, such as arrowheads etc.) and numerous Nemrik points, Helwan-points, and Aswad-points dominate the backfill's lithic inventory. | https://en.wikipedia.org/wiki?curid=515395 |
10,651 | Before any burials were found, Schmidt speculated that graves could have been located in niches behind the walls of the circular building. In 2017, a human crania with incisions was discovered at the site, interpreted as a manifestation of the widespread Neolithic skull cult. Special preparation of human crania in the form of plastered human skulls is known from the Pre-Pottery Neolithic B period at sites such as 'Ain Mallaha, Tell es-Sultan (also known as Jericho), and Yiftahel. | https://en.wikipedia.org/wiki?curid=515395 |
10,652 | The plateau Göbekli Tepe is situated on has been shaped by erosion and quarrying from the Neolithic onwards. There are four and channels on the southern part of the plateau, interpreted as the remains of an ancient quarry from which rectangular blocks were taken. These are possibly related to a square building in the neighbourhood, of which only the foundation is preserved. Presumably, this is the remains of a Roman watchtower that was part of the "Limes Arabicus", though this is conjecture. Most structures on the plateau seem to be the result of Neolithic quarrying, with the quarries being used as sources for the huge, monolithic architectural elements. Their profiles were pecked into the rock, with the detached blocks then levered out of the rock bank. Several quarries where round workpieces had been produced were identified. Their status as quarries was confirmed by the find of a 3-by-3 metre piece at the southeastern slope of the plateau. Unequivocally Neolithic are three T-shaped pillars that had not yet been levered out of the bedrock. The largest of them lies on the northern plateau. It has a length of and its head has a width of . Its weight may be around 50 tons. The two other unfinished pillars lie on the southern Plateau. | https://en.wikipedia.org/wiki?curid=515395 |
10,653 | Archaeologists disagree on how much labour was needed to construct the site. Schmidt maintained that "the work of quarrying, transporting, and erecting tons of heavy, monolithic, and almost universally well-prepared limestone pillars [...] was not within the capability of a few people". Using Thor Heyerdahl's experiments with the moai of Rapa Nui as a reference, he estimated that moving the pillars alone must have involved hundreds of people. According to these experiments, one "moai" of similar size to a T-shaped pillar from Göbekli Tepe would have taken 20 people a year to carve, and 50–75 people a week to transport 15 km. Schmidt's team has also cited a 1917 account of the construction of a megalith on the Indonesian island of Nias, which took 525 people three days. These estimates underpin their interpretation that the site was built by a large, non-resident workforce, coerced or enticed there by a small religious elite. However, others estimate that just 7–14 people could have moved the pillars using ropes and water or another lubricant, with techniques used to construct other monuments such as Stonehenge. Experiments at Göbekli Tepe itself have suggested that all the PPNB structures currently exposed could have been built by 12–24 people in less than four months, allowing for time spent quarrying stone and gathering, and preparing food. These labour estimates are thought to be within the capability of a single extended family or village community in the Neolithic. They also match the number of people that could have comfortably been inside one of the buildings at the same time. | https://en.wikipedia.org/wiki?curid=515395 |
10,654 | The stone pillars in the enclosures at Göbekli Tepe are T-shaped, similar to other PPN sites in the region. Unlike at these other sites, however, many of the pillars are carved – typically in low relief, though sometimes in high relief. Most carvings depict animals, mostly serpents, foxes, and boars, but also gazelle, mouflon (wild sheep), onager, ducks, and vultures. Insofar as they can be identified, the animals are male, and often depicted with an aggressive posture. | https://en.wikipedia.org/wiki?curid=515395 |
10,655 | Abstract shapes are also depicted, mostly an upright or horizontal ‘H’-shaped symbol, but also crescents and disks. Depictions of humans are rare; pillar 43 in enclosure D includes a headless man with an erect phallus. However, the ‘T’-shape of the pillars themselves is anthropomorphic: the shaft is the body, and the top is the head. This is confirmed by the fact that some pillars include – in addition to animal reliefs – carvings of arms, hands, and loincloths. | https://en.wikipedia.org/wiki?curid=515395 |
10,656 | The two central pillars occupied a special place in the symbolic architecture of the enclosures. Those in Enclosure D represent humans, with arms, a belt, and a piece of cloth that hides the genitals. The sex of the individuals depicted cannot be clearly identified, though Schmidt suggested that they are two men because the belts they wear are a male attribute in the period. There is only one certain representation of a woman, depicted naked on a slab. | https://en.wikipedia.org/wiki?curid=515395 |
10,657 | Schmidt and zooarchaeologist Joris Peters have argued that the variety of fauna depicted on the pillars means they likely do not express a single iconography. They suggest that, since many of the animals pictured are predators, the stones may have been intended to stave off evils through some form of magic representation, or served as totems. | https://en.wikipedia.org/wiki?curid=515395 |
10,658 | The structures at Göbekli Tepe have also yielded a number of smaller carved stones, which typically cannot be attributed to one period or another. The iconography of these objects is similar to that of the pillars, mostly depicting animals, but also humans, again primarily male. | https://en.wikipedia.org/wiki?curid=515395 |
10,659 | A broken "totem" was discovered in one of the structures in Layer II. Reassembled, it is 1.92 m high and 30 cm in diameter. It depicts three figures (from top to bottom): a predator (a bear or large felid) with a missing head, and the neck and arms of a human; another figure missing a head with human arms, likely male; and a third figure with a preserved head. Snakes are carved on either side. | https://en.wikipedia.org/wiki?curid=515395 |
10,660 | Klaus Schmidt's view was that Göbekli Tepe was a stone-age mountain sanctuary. He suggested it was a central location for a cult of the dead and that the carved animals are there to protect the dead. Butchered bones found in large numbers from the local game such as deer, gazelle, pigs, and geese have been identified as refuse from food hunted and cooked or otherwise prepared for the congregants. Zooarchaeological analysis shows that gazelle were only seasonally present in the region, suggesting that events such as rituals and feasts were likely timed to occur during periods when game availability was at its peak. Schmidt was the construction of Göbekli Tepe as contributing to the later development of urban civilization. | https://en.wikipedia.org/wiki?curid=515395 |
10,661 | Schmidt also speculated on the belief systems of the groups that created Göbekli Tepe, based on comparisons with other shrines and settlements. He presumed shamanic practices and suggested that the T-shaped pillars represent human forms, perhaps ancestors, whereas he saw a fully articulated belief in deities as not developing until later, in Mesopotamia, that was associated with extensive temples and palaces. This corresponds well with an ancient Sumerian belief that agriculture, animal husbandry, and weaving were brought to humans from the sacred mountain Ekur, which was inhabited by Annuna deities, very ancient deities without individual names. Schmidt identified this story as a primeval oriental myth that preserves a partial memory of the emerging Neolithic. It is apparent that the animal and other images give no indication of organized violence, i.e. there are no depictions of hunting raids or wounded animals, and the pillar carvings generally ignore game on which the society depended, such as deer, in favour of formidable creatures such as lions, snakes, spiders, and scorpions. Expanding on Schmidt's interpretation that round enclosures could represent sanctuaries, Gheorghiu's semiotic interpretation reads the Göbekli Tepe iconography as a cosmogonic map that would have related the local community to the surrounding landscape and the cosmos. | https://en.wikipedia.org/wiki?curid=515395 |
10,662 | The assumption that the site was strictly cultic in purpose and not inhabited has been challenged as well by the suggestion that the structures served as large communal houses, "similar in some ways to the large plank houses of the Northwest Coast of North America with their impressive house posts and totem poles." It is not known why every few decades the existing pillars were buried to be replaced by new stones as part of a smaller, concentric ring inside the older one. According to Rémi Hadad, in recent years "the interpretative enthusiasm that sought to see Göbekli Tepe as a regional ceremonial centre where nomadic populations would periodically converge is giving way to a vision that is more in line with what is known about other large Pre-Pottery Neolithic sites, where ritual and profane functions coexist." For example, the discovery of domestic buildings and rainwater harvesting systems has forced a revision of the 'temple' narrative. | https://en.wikipedia.org/wiki?curid=515395 |
10,663 | Before being documented by archaeologists, the hill Göbekli Tepe stands on, known locally in Kurdish as Girê Mirazan or Xerabreşk, was considered a sacred place. | https://en.wikipedia.org/wiki?curid=515395 |
10,664 | The archaeological site was first noted in a survey conducted by Istanbul University and the University of Chicago in 1963. American archaeologist Peter Benedict identified the stone tools collected from the surface of site as characteristic of the Aceramic Neolithic, but apparently mistook the upper parts of the T-shaped pillars for grave markers. The hill had long been under agricultural cultivation, and generations of local inhabitants had frequently moved rocks and placed them in clearance piles, which may have disturbed the upper layers of the site. At some point, attempts had been made to break up some of the pillars, presumably by farmers who mistook them for ordinary large rocks. | https://en.wikipedia.org/wiki?curid=515395 |
10,665 | In October 1994, German archaeologist Klaus Schmidt, who had previously been working at Nevalı Çori, was looking for evidence of similar sites in the area and decided to re-examine the location described by the Chicago researchers in 1963. Asking in nearby villages about hills with flint, he was guided to Göbekli Tepe by Mahmut and İbrahim Yıldız, the farmers who owned the land the site was situated on. Mahmut Yıldız and his father had previously discovered finds while ploughing there, which they reported to the local museum. Having found similar structures at Nevalı Çori, Schmidt recognized the possibility that the stone slabs were not grave markers as supposed by Benedict, but the tops of prehistoric megaliths. He began excavations the following year and soon unearthed the first of the huge T-shaped pillars. Ultimately he found only three tombs on the eastmost hill-group, which were a pilgrimage destination. Yıldız went on to work on the excavations and serve as the site's guard. | https://en.wikipedia.org/wiki?curid=515395 |
10,666 | Schmidt continued to direct excavations at the site on behalf of the Şanlıurfa Museum and the German Archaeological Institute (DAI) until his death in 2014. Since then, the DAI's research at the site has been coordinated by Lee Clare. , work on the site is conducted jointly by Istanbul University, the Şanlıurfa Museum, and the DAI, under the overall direction of Necmi Karul. Recent excavations have been more limited than Schmidt's, focusing on detailed documentation and conservation of the areas already exposed. | https://en.wikipedia.org/wiki?curid=515395 |
10,667 | Göbekli Tepe was designated a UNESCO World Heritage Site in 2018, recognising its outstanding universal value as "one of the first manifestations of human-made monumental architecture". , less than 5% of the site had been excavated. | https://en.wikipedia.org/wiki?curid=515395 |
10,668 | Conservation work at the site caused controversy in 2018, when Çiğdem Köksal Schmidt, an archaeologist, and widow of Klaus Schmidt, said that damage was caused by the use of concrete and "heavy equipment" during the construction of a new walkway. The Ministry of Culture and Tourism responded that no concrete was used and that no damage had occurred. | https://en.wikipedia.org/wiki?curid=515395 |
10,669 | The M4 carbine (officially Carbine, Caliber 5.56 mm, M4) is a 5.56×45mm NATO, gas-operated, magazine-fed carbine developed in the United States during the 1980s. It is a shortened version of the M16A2 assault rifle. | https://en.wikipedia.org/wiki?curid=321957 |
10,670 | The M4 is extensively used by the United States Armed Forces, with decisions to largely replace the M16 rifle in United States Army (starting 2010) and United States Marine Corps (USMC) (starting 2016) combat units as the primary infantry weapon and service rifle. The M4 has been adopted by over 60 countries worldwide, and has been described as "one of the defining firearms of the 21st century". | https://en.wikipedia.org/wiki?curid=321957 |
10,671 | Since its adoption in 1994, the M4 has undergone over 90 modifications to improve the weapon's ergonomics and modularity, including: the M4A1, which strengthened the barrel and removed the burst-fire option; the SOPMOD, an accessory kit containing optical attachments; and the underbarrel M203 grenade launcher. | https://en.wikipedia.org/wiki?curid=321957 |
10,672 | In April 2022, the U.S. Army selected the SIG MCX SPEAR as the winner of the Next Generation Squad Weapon Program to replace the M16/M4. The rifle is designated XM5. | https://en.wikipedia.org/wiki?curid=321957 |
10,673 | Following the adoption of the M16 rifle, carbine variants were also adopted for close quarters operations, the first of which was the CAR-15 family of weapons, which served through the Vietnam War. However, these rifles had design issues, as the barrel length was halved to , which upset the ballistics, reducing its range and accuracy and leading to considerable muzzle flash and blast, meaning that a large flash suppressor had to be fitted. | https://en.wikipedia.org/wiki?curid=321957 |
10,674 | In 1982, the U.S. Government requested Colt to make a carbine version of the M16A2. At the time, the Colt M16A2 was the Colt 645, also known as the M16A1E1. Later that year, the U.S. Army Armament Munitions Chemical Command helped Colt develop a new variant of the XM177E2, and the U.S. Army redesignated the XM177E2 to the XM4 Carbine, giving the name as the successor to the M3 Carbine. The carbine used the same upper and lower receiver as the M16A1, and fires the M855 cartridge along with the older M193 cartridges. In 1983, the 9th Infantry Division requested a Quick Reaction Program (QRP) for a 5.56mm carbine to replace the M1 Carbine and M3 submachine gun in service. The XM4 was tested by the Army's Armament Research and Development Center (ARDC) in June 1983. Later, the gun was updated with improved furniture, and a barrel with rifling of 1 turn in . The ARDC recommended additional commonality with the M16A2 rifle, as well as lengthening the barrel to . In January 1984, the U.S. Army revised the QRP, and a month later, the Army formally approved development of the new carbine. | https://en.wikipedia.org/wiki?curid=321957 |
10,675 | In June 1985, the Picatinny Arsenal was given a contract to produce 40 prototypes of the XM4. Initially a joint program between the Army and Marines, in 1986 the Army withdrew their funding. The XM4 was finished in 1987, and the Marines adopted 892 for that fiscal year, with the designation "carbine, 5.56mm, M4." Owing to experience from the 1991 Gulf War, the Army gave Colt its first production contracts for M4 carbines in May and July 1993, and M4A1 carbines for SOCOM operators in February 1994. | https://en.wikipedia.org/wiki?curid=321957 |
10,676 | Interest in the M4 Carbine was accelerated after the Battle of Mogadishu (1993), in which Rangers complained that their M16 rifles were "unwieldy", whereas members of Delta Force in the same battle, equipped with the CAR-15, had no such complaints. The M4 Carbine first saw action in the hands of U.S. troops deployed to Kosovo in 1999 in support of the NATO-led KFOR peacekeeping force. It would subsequently be used heavily by U.S. forces during the Global War on Terrorism, including in Operation Enduring Freedom and Operation Iraqi Freedom. In the Army, the M4 had largely replaced M16A2s as the primary weapon of forward deployed personnel by 2005. The M4 carbine also replaced most submachine guns and selected handguns in U.S. military service, as it fires more effective rifle ammunition that offers superior stopping power and is better able to penetrate modern body armor. | https://en.wikipedia.org/wiki?curid=321957 |
10,677 | In 2007, the USMC ordered its officers (up to the rank of Lieutenant Colonel) and staff non-commissioned officers to carry the M4 carbine instead of the M9 handgun. This is in keeping with the Marine Corps doctrine, "Every Marine a rifleman." The Marine Corps, however, chose the full-sized M16A4 over the M4 as its standard infantry rifle. United States Navy corpsmen E5 and below are also issued M4s instead of the M9. While ordinary riflemen in the Marine Corps were armed with M16A4s, M4s were fielded by troops in positions where a full-length rifle would be too bulky, including vehicle operators, fireteam and squad leaders. As of 2013, the U.S. Marine Corps had 80,000 M4 carbines in their inventory. | https://en.wikipedia.org/wiki?curid=321957 |
10,678 | By July 2015, major Marine Corps commands were endorsing switching to the M4 over the M16A4 as the standard infantry rifle, just as the Army had done. This is because of the carbine's lighter weight, compact length, and ability to address modern combat situations that happen mostly within close quarters; if a squad needs to engage at longer ranges, the M27 IAR can be used as a designated marksman rifle. Approval of the change would move the M16 to support personnel, while armories already had the 17,000 M4s in the inventory needed to outfit all infantrymen who needed one. In October 2015, Commandant Robert Neller formally approved of making the M4 carbine the primary weapon for all infantry battalions, security forces, and supporting schools in the USMC. The switch was to be completed by September 2016. In December 2017, the Marine Corps revealed a decision to equip every Marine in an infantry squad with the M27, replacing the M4 in that part of the service. MARSOC will retain the M4, as its shorter barrel is more suited to how they operate in confined spaces. | https://en.wikipedia.org/wiki?curid=321957 |
10,679 | In 2009, the U.S. Army took complete ownership of the M4 design. This allowed companies other than Colt to compete with their own M4 designs. The Army planned on fielding the last of its M4 requirement in 2010. In October 2009, Army weapons officials proposed a series of changes to the M4 to Congress. Requested changes included an electronic round counter that records the number of shots fired, a heavier barrel, and possibly replacing the Stoner expanding gas system with a gas piston system. | https://en.wikipedia.org/wiki?curid=321957 |
10,680 | The benefits of these changes, however, have come under scrutiny from both the military and civilian firearms community. According to a PDF detailing the M4 Carbine improvement plans released by PEO Soldier, the direct impingement system would be replaced only after reviews were done comparing the direct impingement system to commercial gas piston operating system to find out and use the best available operating system in the U.S. Army's improved M4A1. | https://en.wikipedia.org/wiki?curid=321957 |
10,681 | In September 2010, the Army announced it would buy 12,000 M4A1s from Colt Firearms by the end of 2010, and would order 25,000 more M4A1s by early 2011. The service branch planned to buy 12,000 M4A1 conversion kits in early 2011. In late 2011, the Army bought 65,000 more conversion kits. From there the Army had to decide if it would upgrade all of its M4s. In April 2012, the U.S. Army announced it would begin purchasing over 120,000 M4A1 carbines to start reequipping front line units from the original M4 to the new M4A1 version. The first 24,000 were to be made by Remington Arms Company. Remington was to produce the M4A1s from mid-2013 to mid-2014. After completion of that contract, it was to be between Colt and Remington to produce over 100,000 more M4A1s for the U.S. Army. Because of efforts from Colt to sue the Army to force them not to use Remington to produce M4s, the Army reworked the original solicitation for new M4A1s to avoid legal issues from Colt. On 16 November 2012, Colt's protest of Remington receiving the M4A1 production contract was dismissed. Instead of the contract being re-awarded to Remington, the Army awarded the contract for 120,000 M4A1 carbines worth $77 million to FN Herstal on 22 February 2013. The order was expected to be completed by 2018. | https://en.wikipedia.org/wiki?curid=321957 |
10,682 | Replacements for the M4 have mostly focused on two factors: improving its reliability, and its penetration. The first attempt to find a replacement for the M4 came in 1986, with the Advanced Combat Rifle program, in which the caseless Heckler & Koch G11 and various flechette rifles were tested, but this was quickly dropped as these designs were mostly prototypes, which demonstrated a lack of reliability. In the 1990s, the Objective Individual Combat Weapon competition was put forth to find a replacement for the M4. Two designs were produced, both by Heckler & Koch: the XM29 OICW, which incorporated a smart grenade launcher, but was canceled in 2004 as it was too heavy, and the XM8, which was canceled in 2005 as it did not offer significant enough improvements over the M4. | https://en.wikipedia.org/wiki?curid=321957 |
10,683 | The Heckler & Koch HK416 was introduced in 2005, incorporating the same lower receiver as the M4A1, but replacing its direct impingement system with a gas-operated rotating bolt, more comparable to that of the G36. The HK416 was adopted by the Navy SEALs, Delta Force, and other special forces. In 2010, it was adopted by the Marines as the M27 Infantry Automatic Rifle. The same year, the Rangers and Navy SEALs adopted the FN SCAR, but later withdrew their purchase, as it was not a significant enough improvement over the M4A1. | https://en.wikipedia.org/wiki?curid=321957 |
10,684 | After the failure of the Individual Carbine program, the Next Generation Squad Weapon (NGSW) was started in 2017. The program aimed to replace the M4 Carbine and the M249 SAW with weapons that would compensate for their perceived deficiencies when fighting at longer ranges, as well as addressing concerns about the effectiveness of traditional 5.56x45mm ammunition against troops wearing body armor in a future peer or near-peer conflict. In order to achieve these goals, all weapon submissions were to be chambered in a new 6.8x51 mm caliber. | https://en.wikipedia.org/wiki?curid=321957 |
10,685 | SIG Sauer, Textron Systems, FN Herstal, True Velocity (previously Lonestar Future Weapons and General Dynamics), and PCP Tactical took part in the program. Textron submitted a cased-telescoped (CT) ammunition-firing rifle for the program; FN Herstal submitted their HAMR IAR re-chambered in 6.8mm caliber; PCP Tactical submitted a modified Desert Tech MDRx; SIG Sauer submitted a redesigned MCX variant known as the MCX-SPEAR. In early 2022, the program concluded, with SIG Sauer being declared the winner. Their rifle entry was designated the XM5, and their automatic rifle the XM250. Operational testing and fielding are scheduled for 2024. | https://en.wikipedia.org/wiki?curid=321957 |
10,686 | The M4 and its variants fire 5.56×45mm NATO (and .223 Remington) ammunition, and are gas-operated, magazine-fed, selective fire firearms with either a multi-position telescoping stock or a fixed A2 or LE tactical stock. The first stock fitted onto the M4 in 1985 was made entirely of plastic, which only had two positions; fully closed or fully extended. Later models have greater adjustability, and are commonly known as the "six position stock", "M4 stock", or, because of its recesses, "waffle stock". | https://en.wikipedia.org/wiki?curid=321957 |
10,687 | The M4 is a shorter and lighter variant of the M16A2 rifle, with 80% parts commonality. The M4's maneuverability makes it beneficial for non-infantry troops (vehicle crews, clerks and staff officers), as well as for close quarters battle. The M4, along with the M16A4, has mostly replaced the M16A2 in the Army and Marines. The U.S. Air Force, for example, has transitioned completely to the M4 for Security Forces squadrons, while other armed personnel retain the M16A2. The U.S. Navy uses M4A1s for Special Operations and vehicle crews. However, the M4's shorter barrel reduces its range, with its rear iron sights integrated in the (removable) carry handle only adjustable from up to , compared to the M16A2 rear iron sights integrated in the fixed carry handle, which can reach up to . | https://en.wikipedia.org/wiki?curid=321957 |
10,688 | Like all the variants of the M16, the M4 and the M4A1 can be fitted with many accessories, such as night vision devices, flash suppressors, laser sights, telescopic sights, bipods, either the M203 or M320 grenade launcher, the M26 MASS shotgun, forward hand grips, a detachable rail-mounted carrying handle, and anything else compatible with a MIL-STD-1913 picatinny rail. | https://en.wikipedia.org/wiki?curid=321957 |
10,689 | Other common accessories include the AN/PEQ-2, AN/PEQ-15 multi-mode laser, AN/PEQ-16 Mini Integrated Pointing Illumination Module (MIPIM), M68 CCO, Trijicon TA01 and TA31 Advanced Combat Optical Gunsights (ACOG), EOTech 550 series holographic sights, and Aimpoint M68 Close Combat Optic. Visible and infrared lights of various manufacturers are commonly attached using various mounting methods. As with all versions of the M16, the M4 accepts a blank-firing attachment (BFA) for training purposes. | https://en.wikipedia.org/wiki?curid=321957 |
10,690 | The M4 and the M4A1 feed from 30-round STANAG magazines. Other types of magazines with different capacities such as the 100 rounds Beta C-Mag are also available. In January 2017, a USMC unit deployed with suppressors mounted to every infantry M4 service weapon. Exercises showed that having all weapons suppressed improved squad communication and surprise during engagements; disadvantages included additional heat and weight, increased maintenance, and the greater cost of equipping so many troops with the attachment. In July 2020, the Marine Corps announced it would be ordering suppressors for use by all M4 carbines used by close combat units. The Marines began to rollout suppressors for all M4/M4A1 carbines in infantry, reconnaissance and special operations units in December 2020. | https://en.wikipedia.org/wiki?curid=321957 |
10,691 | In 1992, U.S. Special Operations Command (USSOCOM) developed the Special Operations Peculiar Modification (SOPMOD) Block I kit for the carbines used by units operating under its command. The kit features an M4A1, a Rail Interface System (RIS) handguard developed by Knight's Armament Company (KAC), a shortened quick-detachable M203 grenade launcher and leaf sight, a KAC sound suppressor, a KAC back-up rear sight, an Insight Technologies AN/PEQ-2A visible laser/infrared designator, along with Trijicon's ACOG TA-01NSN model and Reflex sights, and a night vision sight, among many other accessories. This kit was designed to be configurable (modular) for various missions, and the kit is currently in service with special operations units. | https://en.wikipedia.org/wiki?curid=321957 |
10,692 | In 2002, the Block II modification kit was adopted featuring two new upper receivers: the Special Purpose Receiver (SPR) and Close Quarter Battle Receiver (CQBR). M4A1s fitted with the SPR were designated by the Navy as the Mk 12 Special Purpose Rifle, a type of designated marksman rifle. M4A1s with the CQBR were designated the Mk 18 Mod 0. | https://en.wikipedia.org/wiki?curid=321957 |
10,693 | In 2018, the Upper Receiver Group-Improved (URG-I) modification kit was approved for the conversion of Block I and Block II carbine's upper receiver "to an improved barrel and rail assembly.." which includes the Magpul Industries M-LOK rail interface system. | https://en.wikipedia.org/wiki?curid=321957 |
10,694 | Variants of the carbine built by different manufacturers are also in service with many other foreign special forces units, such as the Australian Special Air Service Regiment (SASR). While the SASR uses weapons of essentially the same pattern built by Colt for export (Colt uses different models to separate weapons for the U.S. military and those for commercial/export purposes), the British Special Air Service uses a variant on the basic theme, the Colt Canada C8SFW. | https://en.wikipedia.org/wiki?curid=321957 |
10,695 | Colt Model "925" carbines were tested and fitted with the KAC M4 RAS under the designation "M4E2", but this designation appears to have been scrapped in favor of mounting this system to existing carbines without changing the designation. The U.S. Army Field Manual specifies for the Army that adding the Rail Adapter System (RAS) turns the weapon into the "M4 MWS" or "modular weapon system". | https://en.wikipedia.org/wiki?curid=321957 |
10,696 | The M4A1 carbine is a fully automatic variant of the basic M4 carbine intended for special operations use. The M4A1 was introduced in May 1991 and was in service in 1994. The M4A1 was the first M4 model with the removable carry handle. The M4A1 has a "S-1-F" (safe/semi-automatic/fully automatic) trigger group, while the M4 has a "S-1-3" (safe/semi-automatic/3-round burst) trigger group. The M4A1 is used by almost all U.S special operation units including, but not limited to, Marine Force Recon, Army Rangers, Army Special Forces, Navy SEALs, Air Force Pararescue and Air Force Combat Control Teams. It has a maximum effective range of . The fully automatic trigger gives a more consistent trigger pull, which leads to better accuracy. According to Mark A. Westrom, owner of ArmaLite, Inc., automatic fire is better for clearing rooms than burst fire. | https://en.wikipedia.org/wiki?curid=321957 |
10,697 | The M4A1 uses a heavier barrel than the standard M4, as the regular M4 barrel, which can fire 6,000 rounds before requiring a replacement, was not sufficient for the higher consumption of ammunition by SOCOM operators. The redesigned barrel has an increased diameter in the area between the receiver and front sight. | https://en.wikipedia.org/wiki?curid=321957 |
10,698 | Conversion of M4s to the M4A1 began in 2011, as part of the Product Improvement Program, which included the conversion of 300,000 M4 carbines to the M4A1. Though in service with special forces, combat in Afghanistan showed the need for providing automatic suppression fires during fire and movement for regular soldiers. The 101st Airborne Division began fielding newly-built M4A1s in 2012, and the U.S. 1st Infantry Division became the first unit to convert their M4s to M4A1-standard in May 2014. Upgrades included a heavier barrel to better dissipate heat from sustained automatic firing, which also helps the rifles use the M855A1 EPR that has higher proof pressures and puts more strain on barrels. The full-auto trigger group has a more consistent trigger pull, whereas the burst group's pull varies on where the fire control group is set, resulting in more predictable and better accuracy on semi-automatic fire. Another addition is an ambidextrous selector lever for easier use with left-handed shooters. The M4-M4A1 conversion increases weapon weight from to , counting a back-up iron sight, forward pistol grip, empty magazine, and sling. Each carbine upgrade costs $240 per rifle, for a total cost of $120 million for half a million conversions. Three hundred conversions can be done per day to equip a brigade combat team per week, with all M4A1 conversions to be completed by 2019. | https://en.wikipedia.org/wiki?curid=321957 |
10,699 | For the Individual Carbine competition, Colt submitted their "Enhanced M4" design, also known as the Colt Advanced Piston Carbine (APC). The weapon has a suppression-ready fluted barrel, which is lighter and cools better than previous M4 barrels. It is claimed to have "markedly better" accuracy. To improve reliability, Colt used an articulating link piston (ALP), which "reduces the inherent stress in the piston stroke by allowing for deflection and thermal expansion". In traditional gas piston operating systems, the force of the piston striking the bolt carrier can push the bolt carrier downwards and into the wall of the buffer tube, leading to accelerated wear and even chipped metal. This is known as carrier tilt. The ALP allows the operating rod to wiggle to correct for the downward pressure on the bolt and transfers the force straight backwards in line with the bore and buffer assembly, eliminating the carrier tilt. This relieves stress on parts and helps to increase accuracy. The Individual Carbine competition was canceled before a winning weapon was chosen. | https://en.wikipedia.org/wiki?curid=321957 |
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