Metal M16 Airsoft Gun

The M16 is a light-weight, 5.56 mm caliber, air-cooled, gas-operated, magazine-fed attack rifle, with a revolving bolt, actuated by direct impingement gas operation.

The rifle is formed of steel, aluminum, and composite plastics. The U.S. Air Force's rifle, the M16, and the U.S. Military's rifle, the XM16E1, were the 1st versions of the M16 rifle fielded. Shortly , the division homogenized the XM16E1 as the M16A1 rifle, an M16 with a forward aid feature requested by the division. All the early versions were chambered to launch the M193 / M196 cartridge in the semi-automatic and the automated firing modes. This took place in the early 1960s, with the division issuing it in late 1964.

Commercial AR-15s were first provided to Special Forces troops in spring of 1964. The M16's receivers are made from aluminum amalgamate, its barrel, bolt, and bolt carrier of steel, and its handguards, pistol grip, and buttstock of plastics. Early models were particularly lightweight at 6.5 lb ( 2.9 kg ) without magazine and sling. This was noticeably less than older 7.62 mm "battle rifles" of the 1950s and 1960s. It also compares with the 6.5 lb ( 2.9 kg ) AKM without mag. M16A2 and later variants weigh more ( 8.5 lb ( 3.9 kg ) loaded ) due to the adoption of a thicker barrel profile. The thicker barrel is more impervious to damage when handled approximately and is also slower to overheat during sustained fire.

Unlike a conventional "bull" barrel that is thick its complete length, the M16A2's barrel is only thick forward of the handguards. The barrel profile under the handguards stayed the same as the M16A1 for compatibility with the M203 grenade launcher. The rifle is identical length as the M16A2.

One particular ergonomic feature is a plastic or metal stock immediately behind the action, which has a recoil spring. This serves the twin function of operating spring and recoil buffer. The stock being in accordance with the bore reduces muzzle rise, particularly during automated fire. Because recoil does not seriously shift the point of target, quicker follow-up shots are possible and user fatigue is reduced. Another particular ergonomic feature is a carrying handle on top of the receiver, with an integrated rear sight assembly and charging handle. This design is a by-product of the first design where the carry handle served to give protection to the charging handle and mount a scope. In practice, the handle is never used to hold the weapon and doing so is expressly proscribed in numerous army bodies, as it is considered dangerous. Holding the weapon by the pistol grip provides faster reply time and better "muzzle awareness," while a shoulder sling gives a more convenient option when reply time isn't a concern.

As significantly, with the sight plane 2.5 in ( 63.5 mm ) over the bore, the M16 has an inherent parallax problem that may be confounding to shooters. At closer ranges ( typically within 1520 meters ), the shooter must target high to set shots where desired. Newer models have a "flattop" higher receiver with a Picatinny mounting rail, to that the user can attach either a traditional sighting system or many optical devices like night vision scopes. The M16 uses direct impingement gas operation ; power from hi-pressure gas tapped from a non-adjustable port built into the front sight assembly induces the moving parts in the weapon.

Combustion gases travel via a gas tube above the barrel right into a chamber in the bolt carrier behind the bolt itself, pushing the carrier away from the bolt. This decreases the quantity of moving parts by getting rid of the requirement for a new piston and cylinder and it provides better performance in fast fire by keeping reciprocating masses on the same axis as the bore.