The M16 is still a general-issue rifle with the US Armed forces. It is also widely used by the US Law Enforcement agencies, either in military form (for example, the LAPD had some M16s, retired from Army), or in "civilian" semi-automatic only form. The AR-15 style rifles are made in the USA by at least dozen large companies, such as Armalite, Bushmaster, Colt, FN Manufacturing, Hesse, Les Baer, Olympic, Wilson Combat, and by number of smaller companies, many of which do assembly their rifles from components made by some other major manufacturers. M16-type rifles also manufactured outside of the USA, most notably in the Canada, by Diemaco Co. China also makes some AR-15 type rifles at NORINCO state factories. M16 rifles are used by many foreign military groups, most notably the British SAS, who preferred the M16 over the infamous L85A1 rifle, and by many others.
At the present time almost all initial flaws of the M16 are bugged out, and it is considered among the best assault rifles in the world. While its reliability in the harsh conditions cannot match reliability of its main rival, the Kalashnikov AK-47 and AK-74, it is still a quite reliable rifle, especially when well maintained. It is also comfortable to fire and quite accurate.
One of the key advantages of the Stoner design, that must be especially stressed, is the extreme flexibility of the construction. At the present time the interchangeable complete "uppers" are available in various barrel lengths and profiles (from 7 to 24 inches long, slim and heavy), in dozens of rifle and pistol calibers (from tiny but fast .17 Remington and up to monstrous .458 SOCOM, and from .22LR and 9mm Luger up to mighty .50AE). Special, manually single-shot uppers are commercially available in the extremely powerful .50BMG (12.7x99mm) caliber. Various "lowers" offer a broad variety of trigger units, buttstocks and other options. This advantage is viable for both military (especially Spec Ops), Law Enforcement, and civilian applications, as it allows to tailor any particular AR-15 type rifle to the current situation and tactical needs.
M16 / AR-15 Technical description
The original AR-15 rifle is a gas operated, selective fire, magazine fed weapon. Every rifle from the M16 family is generally the same, but most civilian AR-15 type rifles are semi-automatic only.
The heart of the AR-15 is the direct gas system, developed by the Eugene Stoner in the early 1950s. This system uses no conventional gas piston and rod to propel bolt group back after the shot is fired. Instead, the hot powder gases are fed from the barrel and down to the stainless steel tube into the receiver. Inside the receiver, the rear end of the gas tube enters into the "gas key", a small attachment on the top of the bolt carrier. The hot gases, through the gas key, enter the hollow cavity inside the bolt carrier, and expands there, acting against the bolt carrier and the collar around the bolt body. The pressure of the gases causes the bolt carrier to move back against initially stationary bolt. The linear rearward movement of the carrier initially transferred into the rotation of the bolt, via the cam slot in the bolt carrier and the cam pin, attached to the bolt, that followed the slot. As soon as the bolt is rotated to unlock from the barrel, the bolt group continues its rearward travel under the inertia and the residual pressure in the barrel, extracting the spent case and compressing the buffer return spring, located in the buttstock. The forward movement of the bolt group first strips the fresh cartridge from the magazine and, on the final stage of the movement, rotates the bolt to lock into the barrel extension. The bolt has 7 radial locking lugs, eight lug is located on the extractor claw. Since the introduction of the XM16E1 rifle, the forward assist device is used on all military and most civilian AR-15 type rifles. This device consist of the spring-loaded button with internal claw, that engages the serrations on the right side of the bolt carrier to push it forward, if the pressure of the return spring is insufficient to do so (for example, due to the fouling inside the receiver or chamber). The rifle will not fire unless the bolt is locked and the bolt carrier is in its forwardmost position. The bolt carrier and the bolt itself are chrome-plated. Another feature of the AR-15 type rifles is the bolt catch device, that locks the bolt group in the open position when the last round is fired. To release the bolt group one must push the button, located at the left side of the receiver, above the magazine. The "T"-shaped cocking handle is located at the rear of the receiver, above the buttstock, and does not reciprocate when gun is fired.
The trigger/hammer group is basically similar to one, found in M1 Garand rifle, and, actually, traces its roots back to the early 1900s, when the great John M. Browning developed his famous Auto-5 semiautomatic shotgun. This basically consists of a hammer, a trigger, a disconnector, a full auto sear and some springs. The fire selector / safety switch is located at the left side of the receiver, above the pistol grip, and is easily operated by the right hand thumb. This switch has 3 positions: "safe", "semi" (single shots), and "auto" (full automatic on M16A1 and A3) or "burst" (3 rounds bursts, on M16A2 and A4). In the latter case (on the M16A2 and A4 rifles), the trigger unit also includes the ratchet device to count the shots fired.
The ejection port is located at the right side of the receiver, and is closed by the spring-loaded dust cover, which automatically pops open when bolt carrier is pulled back. The M16A2 also featured the spent case deflector - a triangular bulb on the receiver, just behind the ejection port, that allows the gun to be safely fired left-handed.
The M16 is fed using box magazines. Earliest magazines were made from aluminum and held 20 rounds. Circa 1970 the new, 30 rounds magazines were introduced into service and these magazines are still in service now. An extremely wide variety of magazines available on the commercial marked, starting from the "US post-ban" 5 and 10 round magazines, and up to 40-rounds box, 90-rounds helical, 100-rounds dual drums (Beta-C) and 120-rounds single drums.
The receiver is made from aluminum alloy, and consists of two parts - "upper receiver" and "lower receiver" (sometimes referred simply as "upper" and "lower"). Most receivers are made from aluminum forgings by machining, but some commercially available receivers are made from aluminum castings with final drilling and machining. The upper and lower receivers are linked by two cross-pins - one at the front (pivot pin), and one at the rear, above the pistol grip (takedown pin). To field strip the AR-15, one must push the rear pin to the right as far as it will go, and then hinge the upper receiver around the front pin. This will allow the bolt group and the carrying handle to be removed from the upper receiver. For further disassembly, the front pin also must be pushed out, and the upper and lover receiver can be separated. The key benefit of this design is the great flexibility - if all components available are made to the same specifications (in most cases they are), one can easily swap various upper receivers on one lower receiver and vice versa. Since the complete "upper" module consist also of the bolt group and the barrel with the gas system, one can easily have different barrel lengths, styles (light, heavy, fluted, bull), and even calibers, for one "lower" group, that consists of the lower receiver with the trigger/hammer unit, recoil buffer, pistol grip and the buttstock.
The furniture on military rifles is made from the black plastic, hence the common name "the black rifle". On the early AR-15 and M16A1 rifles, the handguards were of triangular cross-section, and were made from two non-interchangeable parts. On the M16A2 and latter rifles, the handguards are of round cross-section, and have two interchangeable upper-lower sections. The buttstock on the M16A2 is similar in design to one of M16A1, but slightly longer. The one disadvantage of the Stoner system is that it can not be adapted for conventional folding buttstock. Instead, if required, a telescoped stock is used, that allows to shorten the rifle when required by about the half of the length of the standard stock. M16 is usually equipped with sling, and can accept a knife - bayonet, either an old style M7, or a newer style M9. The flash hiders on the earliest AR-15s and M16s were prong-type, with three open slots, but later were replaced with "bird-cage" flash hiders with four (M16A1) or five (M16A2) slots.
Both M16A1 and M16A2 can be equipped with underbarrel 40mm M203 grenade launcher. M203 mount replaces the standard handguards on the rifle and requires a grenade launcher sight to be mounted on the carrying handle.
Standard sights of the M16A1 consist of a protected front post, mounted on the gas block, and of an aperture flip-up rear, with 2 range settings. Rear sights are mounted within the carrying handle and are adjustable for windage. The A2 style rear sight also features an flip-up, dual aperture sights, with one smaller aperture for daylight usage, and another larger aperture for low light conditions. The range adjustments are made by the rotating knob, located just under the sight. The front sight is generally the same as on the M16A1. The M16A3 and A4 rifles have detachable carrying handles with A2 sights, and the Picatinny-type MilStd rail on the top of the receiver, that can accept a wide variety of sighting devices and mounts. best replica watches