Variants M16 rifle

1 variants

1.1 m16
1.2 xm16e1 , m16a1 (colt model 603)
1.3 m16a2
1.4 m16a3
1.5 m16a4
1.6 summary of differences

variants

m16

this first m16 variant adopted operationally, u.s. air force. equipped triangular handguards, butt stocks without compartment storage of cleaning kit, three-pronged flash suppressor, full auto, , no forward assist. bolt carriers chrome plated , slick-sided, lacking forward assist notches. later, chrome plated carriers dropped in favor of army issued notched , parkerized carriers though interior portion of bolt carrier still chrome-lined. air force continued operate these weapons until around 2001, @ time air force converted of m16s m16a2 configuration.

the m16 adopted british sas, used during falklands war.

xm16e1 , m16a1 (colt model 603)

an m16 rifle: note duckbill flash suppressor, triangular grip, forward assist, , lack of brass deflector

the u.s. army xm16e1 same weapon m16 addition of forward assist , corresponding notches in bolt carrier. m16a1 finalized production model in 1967.

to address issues raised xm16e1 s testing cycle, closed, bird-cage flash suppressor replaced xm16e1 s three-pronged flash suppressor caught on twigs , leaves. various other changes made after numerous problems in field. cleaning kits developed , issued while barrels chrome-plated chambers , later lined bores introduced.

with these , other changes, malfunction rate declined , new soldiers unfamiliar problems. rib built side of receiver on xm16e1 prevent accidentally pressing magazine release button while closing ejection port cover. rib later extended on production m16a1s in preventing magazine release inadvertently being pressed. hole in bolt accepts cam pin crimped inward on 1 side, in such way cam pin may not inserted bolt installed backwards, cause failures eject until corrected. m16a1 no longer in service united states, still standard issue in many world armies.

m16a2

m16a2



new rear sight, brass deflector , forward assist of m16a2



a u.s marine m16a2 on training exercise @ camp baharia, iraq, 2004

the development of m16a2 rifle requested united states marine corps result of usmc s combat experience in vietnam xm16e1 , m16a1. officially adopted department of defense rifle, 5.56mm, m16a2 in 1982. marines first branch of u.s. armed forces adopt m16a2 in early/mid-1980s, united states army following suit in late 1980s. modifications m16a2 extensive. in addition new rifling, barrel made greater thickness in front of front sight post, resist bending in field , allow longer period of sustained fire without overheating. rest of barrel maintained @ original thickness enable m203 grenade launcher attached. new adjustable rear sight added, allowing rear sight dialed in specific range settings between 300 , 800 meters take full advantage of ballistic characteristics of new ss109 rounds , allow windage adjustments without need of tool or cartridge. weapon s reliability allowed used around united states marine corps special operations divisions well. flash suppressor again modified, time closed on bottom not kick dirt or snow when being fired prone position, , acting recoil compensator. front grip modified original triangular shape round one, better fit smaller hands , fitted older models of m16. new handguards symmetrical armories need not separate left , right spares. handguard retention ring tapered make easier install , uninstall handguards. notch middle finger added pistol grip, more texture enhance grip. buttstock lengthened ⁄8 in (15.9 mm). new buttstock became ten times stronger original due advances in polymer technology since 1960s. original m16 stocks made fiberglass-impregnated resin; newer stocks engineered dupont zytel glass-filled thermoset polymers. new stock included textured polymer buttplate better grip on shoulder, , retained panel accessing small compartment inside stock, used storing basic cleaning kit. heavier bullet reduces muzzle velocity 3,200 feet per second (980 m/s), 3,050 feet per second (930 m/s). a2 uses faster twist rifling allow use of trajectory-matched tracer round. has 1:7 twist rate. spent case deflector incorporated upper receiver behind ejection port prevent cases striking left-handed users.

the action modified, replacing automatic setting three-round burst setting. when using automatic weapon, inexperienced troops hold down trigger , spray when under fire. u.s. army concluded three-shot groups provide optimum combination of ammunition conservation, accuracy, , firepower. usmc has retired m16a2 in favor of newer m16a4; few m16a2s remain in service u.s. army reserve , national guard, air force, navy , coast guard.

m16a3

the m16a3 modified version of m16a2 adopted in small numbers u.s. navy seal, seabee, , security units. features m16a1 trigger group providing safe, semi-automatic. , automatic modes instead of a2 s safe, semi-automatic, , burst.

m16a4

united states marine corps m16a4 rifle picatinny rail , foregrip.

the m16a4 fourth generation of m16 series. equipped removable carrying handle , full length quad picatinny rail mounting optics , other ancillary devices. fn m16a4, using safe/semi/burst selective fire, became standard issue u.s. marine corps , current issue marine corps recruits in both mcrd san diego , mcrd parris island.

military issue rifles equipped knight s armament company m5 ras hand guard, allowing vertical grips, lasers, tactical lights, , other accessories attached, coining designation m16a4 mws (or modular weapon system) in u.s. army field manuals.

colt produces m16a4 models international purchases, specifics selective fire:

r0901 / nsn 1005-01-383-2872 (safe/semi/auto)
r0905 (safe/semi/burst)

a study of significant changes marine m16a4 rifles released in february 2015 outlined several new features added inexpensive , available components. features included: muzzle compensator in place of flash suppressor manage recoil , allow faster follow-on shots, though @ cost of noise , flash signature , potential overpressure in close quarters; heavier and/or free-floating barrel increase accuracy 4.5 moa potentially 2 moa; changing reticle on rifle combat optic chevron-shaped semi-circle dot @ center used in m27 iar s squad day optic not obscure target @ long distance; using trigger group more consistent pull force, reconsideration of burst capability; , addition of ambidextrous charging handles , bolt catch releases easier use left-handed shooters.

in 2014, marine units provided limited number of adjustable stocks in place of traditional fixed stock m16a4s issue smaller marines have trouble comfortably reaching trigger when wearing body armor. adjustable stocks added standard authorized accessory, meaning units can use operations , maintenance funds purchase more if needed.

the marine corps had long maintained full-length m16 standard infantry rifle, in october 2015 switch m4 carbine approved standard-issue weapon, giving marine infantrymen smaller , more compact weapon. enough m4s in inventory re-equip necessary units september 2016, , m16a4s moved support , non-infantry marines.

summary of differences