Reliability M16 rifle

m16 direct impingement gas system



m16 direct impingement gas system



101st airborne trooper carrying m16a1 20-round magazine during vietnam war, circa 1969.



101st airborne troopers on line m16a1s during vietnam war, circa 1969



101st airborne trooper on patrol m16a1 during vietnam war, circa 1969



101st airborne troopers on patrol m4s in sadr city, iraq, c. 2006

during part of career, m16 had reputation poor reliability , malfunction rate of 2 per 1000 rounds fired. m16 s action works passing high pressure propellant gasses tapped barrel down tube , carrier group within upper receiver, , commonly referred direct impingement gas system . gas expands within donut shaped gas cylinder within carrier. because bolt prevented moving forward barrel, carrier driven rear expanding gasses , converts energy of gas movement of rifle’s parts. bolt bears piston head , cavity in bolt carrier piston sleeve. more correct call internal piston system. design lighter , more compact gas-piston design. however, design requires combustion byproducts discharged cartridge blown receiver well. accumulating carbon , vaporized metal build-up within receiver , bolt-carrier negatively affects reliability , necessitates more intensive maintenance on part of individual soldier. channeling of gasses bolt carrier during operation increases amount of heat deposited in receiver while firing m16 , causes essential lubricant burned off . requires frequent , generous applications of appropriate lubricant. lack of proper lubrication common source of weapon stoppages or jams.

the original m16 fared poorly in jungles of vietnam , infamous reliability problems in harsh environment. result, became target of congressional investigation. investigation found that:

the m16 billed self-cleaning (when no weapon or ever has been).
the m16 issued troops without cleaning kits or instruction on how clean rifle.
the m16 , 5.56×45mm cartridge tested , approved use of dupont imr8208m stick powder, switched olin mathieson wc846 ball powder produced more fouling, jammed action of m16 (unless gun cleaned , often).
the m16 lacked forward assist (rendering rifle inoperable when jammed).
the m16 lacked chrome-plated chamber, allowed corrosion problems , contributed case extraction failures (which considered severe problem , required extreme measures clear, such inserting cleaning-rod down barrel , knocking spent cartridge out).

when these issues addressed , corrected m16a1, reliability problems decreased greatly. according 1968 department of army report, m16a1 rifle achieved widespread acceptance u.s. troops in vietnam. men armed m16 in vietnam rated rifle s performance high, however, many men entertained misgivings m16 s reliability. when asked weapon preferred carry in combat, 85 percent indicated wanted either m16 or [smaller] submachine gun version, xm177e2. m14 preferred 15 percent, while less 1 percent wished carry either stoner rifle, ak-47, carbine or pistol. in march 1970, president’s blue ribbon defense panel concluded issuance of m16 saved lives of 20,000 u.s. servicemen during vietnam war, have otherwise died had m14 remained in service. however, m16 rifle s reputation continues suffer.

after introduction of m4 carbine, found shorter barrel length of 14.5 inches has negative effect on reliability, gas port located closer chamber gas port of standard length m16 rifle: 7.5 inches instead of 13 inches. affects m4’s timing , increases amount of stress , heat on critical components, thereby reducing reliability. in 2002 assessment usmc found m4 malfunctioned 3 times more m16a4 (the m4 failed 186 times 69,000 rounds fired, while m16a4 failed 61 times). thereafter, army , colt worked make modifications m4s , m16a4s in order address problems found. in tests conducted in 2005 , 2006 army found on average, new m4s , m16s fired approximately 5,000 rounds between stoppages.

in december 2006, center naval analyses (cna) released report on u.s. small arms in combat. cna conducted surveys on 2,608 troops returning combat in iraq , afghanistan on past 12 months. troops fired weapons @ enemy targets allowed participate. 1,188 troops armed m16a2 or a4 rifles, making 46 percent of survey. 75 percent of m16 users (891 troops) reported satisfied weapon. 60 percent (713 troops) satisfied handling qualities such handguards, size, , weight. of 40 percent dissatisfied, size. 19 percent of m16 users (226 troops) reported stoppage, while 80 percent of experienced stoppage said had little impact on ability clear stoppage , re-engage target. half of m16 users never experienced failures of magazines feed. 83 percent (986 troops) did not need rifles repaired while in theater. 71 percent (843 troops) confident in m16 s reliability, defined level of soldier confidence weapon fire without malfunction, , 72 percent (855 troops) confident in durability, defined level of soldier confidence weapon not break or need repair. both factors attributed high levels of soldiers performing own maintenance. 60 percent of m16 users offered recommendations improvements. requests included greater bullet lethality, new-built instead of rebuilt rifles, better quality magazines, decreased weight, , collapsible stock. users recommended shorter , lighter weapons such m4 carbine. issues have been addressed issuing of improved stanag magazine in march 2009, , m855a1 enhanced performance round in june 2010.

in 2010, 2 journalists new york times spent 3 months soldiers , marines in afghanistan. while there, questioned around 100 infantry troops reliability of m16 rifles, m4 carbine. troops did not report reliability problems rifles. while 100 troops asked, engaged in daily fighting in marja, including least dozen intense engagements in helmand province, ground covered in fine powdered sand (called moon dust troops) can stick firearms. weapons dusty, wet, , covered in mud. intense firefights lasted hours several magazines being expended. 1 soldier reported jam when m16 covered in mud after climbing out of canal. weapon cleared , resumed firing next chambered round. furthermore, marine chief warrant officer responsible weapons training , performance of third battalion, sixth marines, reported ve had nil in way of problems; ve had no issues. battalion s 350 m16s , 700 m4s.