STANAG magazine A STANAG magazine or NATO magazine is a type of detachable firearm magazine proposed by NATO in October 1980 . Shortly after NATO ' s acceptance of the 5 . 56x45mm NATO rifle cartridge , Draft Standardization Agreement ( STANAG ) 4179 was proposed in order to allow the military services of member nations easily to share rifle ammunition and magazines during operations , at the individual soldier level , in the interest of easing logistical concerns . The magazine proposed for standardization was originally designed for the U . S . M16 rifle . Many NATO member nations , but not all , subsequently developed or purchased rifles with the ability to accept this type of magazine . However the standard was never ratified and remains a ' Draft STANAG ' . Capacity . The standard capacity of a magazine is 30 rounds . STANAG - compatible magazines can be made to almost any capacity , though those used for military service usually hold 20 or 30 rounds of 5 . 56x45mm NATO ammunition . 40 and 50 - round box magazines as well as 90 - round drum magazine s and 100 - round Beta C - Mag drum magazines designed to comply with STANAG 4179 have also been manufactured . Magpul recently filed a patent for a STANAG - compatible casket magazine and another was released by SureFire in December 2010 as the High Capacity Magazine ( HCM ) with an ammo capacity of 60 to 100 rounds . A Surefire 60 - round magazine has reportedly been used in combat in Afghanistan . Issues and improvements . The STANAG - compatible box magazine , while relatively compact compared to other types of 5 . 56x45mm NATO box magazines , has often been criticized for a perceived lack of durability and a tendency to malfunction unless treated with a level of care that often cannot be afforded under combat conditions . Because STANAG 4179 is only a dimensional standard , production quality from manufacturer to manufacturer is not uniform . Magazines have been manufactured with lightweight aluminum or plastic bodies and other inexpensive materials in order to keep costs down , or to meet requirements that treat the magazine more as a disposable piece of equipment than one that is supposed to stand up to repeated combat use . These problems have been addressed by several manufacturers , most notably Heckler & Koch , who designed a new 30 - round STANAG - compatible box magazine during their contract to rebuild and improve the SA80 rifle for the United Kingdom . As a result , several manufacturers now offer improved STANAG - compatible magazines as well as high - grade stainless steel bodies , rust - and set - resistant chrome - silicon springs , and anti - tilt followers as upgrade components for existing STANAG magazines . In March 2009 , Brownells began delivering 60 , 000 of 1 . 4 million improved STANAG magazines to the U . S . military . To increase reliability , the improved magazine incorporates a heavier , more corrosion resistant spring and a new tan - colored follower that does not tilt inside the casing . Polymer magazines . In 2007 , Magpul Industries released its PMAG , a highly reliable polymer magazine made for use in M16 rifle s . The polymer is found by soldiers to be more rugged than the aluminum STANAG - type magazines . In April 2012 , TACOM issued a “ safety of use message ” notifying troops that non - USGI magazines , like the PMAG , had been put on an unauthorized list , and that they were only allowed to use standard - issue aluminum STANAGs . Soldiers were confused by this , as PMAGs had an Army - approved national stock number ( NSN ) to allow units to order them through the Army supply system . TACOM said that the NSN issued for PMAGs was never authorized or included in technical manuals . The notice was that only Army - authorized magazines listed in the technical manuals could be used , and that just because the PMAG had an NSN , it did not mean the Army was an authorized user . Troops were restricted to using older STANAG magazines with green followers until they could be issued the improved version with the tan follower . The Army reportedly realized in 2007 that the PMAG had better reliability , but did not think Magpul would give up technical data rights . They tried unsuccessfully to develop their own polymer magazine , so they created the improved aluminum STANAG magazine in 2009 with a tan self - leveling / anti - tilt follower with an extended rear leg and modified bullet protrusion for improved round stacking and orientation . The improved magazine reduces the risk of magazine - related stoppages by more than 50 percent , but users still report similar deficiencies that the green follower model had including double feeds , rounds not feeding correctly , getting bent at the opening , and getting crushed in the middle , if only occurring half as much . No information was released about how the improved magazine faired in comparison with the PMAG , which had gained a reputation for reliability , including firing 40 PMAGs through an M4 without a single stoppage , and working after being run over by a heavy armored vehicle . On 6 June 2012 , the Army acknowledged that the TACOM message was not an order or directive , and was optional for troops and commanders to consider , which allowed them to keep using their PMAGs . They clarified that TACOM maintenance information messages are permissive , and that the release was poorly written and had soldiers jumping to conclusions . Sources claim the message was released at that time in relation to the $ 10 . 7 million contract to Brownells to produce 1 . 4 million improved STANAG magazines by January 2010 . Officials contend that limited side - by - side testing found that no commercial magazine was superior to the improved magazine . The TACOM message was intended to make soldiers aware that not all commercial magazines had gone through the same testing as the improved magazine , but they will not be stopped from using PMAGs . In August 2012 , the Israeli Defense Forces adopted the CAA Tactical Mag 17 polymeric magazine to replace their aluminum STANAG magazines . It was chosen over plastic , aluminum , and polymeric designs from other companies , and 10 , 000 magazines were ordered . The Mag 17 will save money from its longevity , as it can be reloaded several dozen times in comparison with 7 times for an aluminum magazine , and is much harder to break . On November 26 , 2012 , the U . S . Marine Corps banned all non - USGI magazines , including the PMAG . The reason was that it was not compatible with the newly issued M27 IAR . In response , Magpul began the process of arranging verification and official testing for its newer PMAG 30 GEN M3 polymer magazine , which is compatible with both the M27 and M16 - series rifles . Firearms compatible with STANAG magazines . Non - AR - 15 / M16 type rifles . Some firearms , while not originally manufactured to feed from STANAG magazines , can be converted to use them . An example is the Austrian Steyr AUG assault rifle , for which an alternate stock assembly is available to allow the use of STANAG magazines . Also the German Heckler & Koch G36 assault rifle features a " modular magazine well " system . This allows the original magazine well , engineered to feed from the proprietary translucent plastic magazine , to be replaced with one that accepts STANAG magazines . Magnolia States Armory offers an adapter that allows the use of STANAG magazines in . 223 Galil rifles as well as one that works in AK47 platform Saiga , WASR3 and Norinco . 223 rifles .