Editing M16 rifle (section)

===Magazines===
[[File:Stanag mags.jpg|thumb|right|Vietnam War-era 20-round magazine (left) and current issue NATO STANAG 30-round magazine (right)]]
[[File:Improved M16 Magazine Follower.jpg|thumb|Improved tan colored M16 magazine follower]]

The M16's magazine was meant to be a lightweight, disposable item.{{sfnp|Bartocci|2011|p=1}} As such, it is made of pressed/stamped aluminum and was not designed to be durable.{{sfnp|Ehrhart|2009|p=39-44}} The M16 originally used a 20-round magazine which was later replaced by a bent 30-round design. As a result, the magazine follower tends to rock or tilt, causing malfunctions.{{sfnp|Bartocci|2011|p=1}} Many non-U.S. and commercial magazines have been developed to effectively mitigate these shortcomings, e.g., Heckler & Koch's all-stainless-steel "High-Reliability" magazine, [[Magpul]]'s polymer P-MAG and E-MAG, etc.{{sfnp|Ehrhart|2009|p=39-44}}{{sfnp|Bartocci|2011|p=1}}

Production of the 30-round magazine started late 1967 but did not fully replace the 20-round magazine until the mid-1970s.{{sfnp|Bartocci|2011|p=1}} Standard USGI aluminum 30-round M16 magazines weigh {{convert|0.11|kg|lb|abbr=on|order=flip}} empty and are {{convert|7.1|in|cm|abbr=out}} long.{{sfnp|Colt, ''M4 5.56mm Carbine''|2003}}{{NoteTag|Per Surefire" "Standard MILSPEC USGI 30-Round Magazine Specs: Height: 7.1" and Weight-Empty: 3.9 ounces"{{Sfnp|Crane|2010|p=1}}}} The newer plastic magazines are about a half-inch longer.{{sfnp|Crane|2010|p=1}} The newer steel magazines are about 0.5-inch longer and four ounces heavier.{{sfnp|Heckler & Koch|2013|p=1}} The M16's magazine has become the unofficial [[NATO]] [[STANAG magazine]] and is currently used by many Western nations, in numerous weapon systems.{{sfnmp|1a1=Dockery|1y=2007|1pp=125-126|2a1=Rottman|2y=2011|2pp=35-36}}

In 2009, the U.S. military began fielding an "improved magazine" identified by a tan-colored follower.{{sfnmp|1a1=PEO Soldier|1y=2009|1p=1|2a1=PEO Soldier|2y=2010|2p=1}} "The new follower incorporates an extended rear leg and modified bullet protrusion for improved round stacking and orientation. The self-leveling/anti-tilt follower minimizes jamming while a wider spring coil profile creates even force distribution. The performance gains have not added weight or cost to the magazines."{{sfnp|PEO Soldier|2010|p=1}}

In July 2016, the U.S. Army introduced another improvement, the new Enhanced Performance Magazine, which it says will result in a 300% increase in reliability in the M4 carbine. Developed by the [[United States Army Armament Research, Development and Engineering Center]] and the [[United States Army Research Laboratory|Army Research Laboratory]] in 2013, it is tan colored with blue follower to distinguish it from earlier, incompatible magazines.{{sfnp|'Soldier Systems Daily,'8 August 2016}}