Meanwhile, a clean-burning powder was substituted for the inferior propellant, and more reliable primers were produced. In addition, the Army had Colt modify the basic M16 to the M16A1 configuration with a chrome-plated chamber (to avoid fouling) and a stiffer buffer spring to decrease and stabilize the automatic firing rate. The extractor mechanism was also modified, to keep fired cartridges from jamming. And a program of intense training taught troops deployed in the field to properly clean, lubricate, and maintain their M16s. In consequence, the reliability of the M16 improved dramatically, along with the attitude of the soldiers and Marines using it. Eventually, the M16A1 became the standard combat rifle for the U.S. Army and Marine Corps and many allied countries during the late 1960s and 1970s. After its early problems were resolved, the M16A1 developed a solid reputation for performance and reliability. It may not have had the glamor of combat rifles like the H&K-91 or the Israeli Galil, but the M 16A1 did the job during the lean years after Vietnam.
In the late 1970s the Army began a major update on the M 16. Topping the wish list were a better forward grip, more accurate sights, and an automatic burst limiter to conserve ammunition. Introduced in 1983, the M 16A2 is in use by the U.S. armed forces today. The features added to the A2 were:
• A heavier and stiffer barrel, for improved accuracy and reduced wear. In addition, the rifling on the barrel has been optimized for new NATO standard M855/SS 109-type 5.56mm (.223-in.) ammunition used by the M249 Squad Automatic Weapon (SAW). It can also fire earlier M193 5.56mm/.223-in. ammunition without modification to the weapon.
• A three-round burst limiter, which restricts "automatic" firing to only three shots per trigger pull.
• A muzzle compensator designed to reduce barrel rise and displacement during automatic firing.
• A plastic handgrip with a round contour which is tougher and easier to grip.
• A plastic buttstock that is lighter and tougher than that on the Al model.
• An improved rear sight deck, with adjustments for range and windage.
• A modified upper receiver assembly which can be easily adapted to deflect ejected cartridges away from the face of left-handed shooters.
• Fittings for the new combat bayonet.
For $624.00 per unit, the M 16A2 is quite a bargain for the American taxpayer, as results from Desert Storm proved.
The first time you pick up an M 16A2, you are struck with the feeling that you are holding a serious piece of machinery. Weighing 8.8 lb/4 kg, the M16A2 feels good in your hands — well balanced and deadly. It is 39.6 in./100.7 cm long, and consists of four major assemblies:
• Lower receiver and buttstock.
• 5.56mm/.223-in. bolt carrier.
• Upper receiver and sight.
• Barrel and forward grip.
The four assemblies break down quickly for cleaning and maintenance. This is easy to learn, even in the dark with your eyes closed. Keeping the M16A2 clean is vitally important, because the components fit very tightly, and any grit or dirt can easily jam or foul the weapon. The Marine Corps is lavish in supplying cleaning kits, pads, and CLP lubricant/cleaner. You can always tell a seasoned combat Marine, because he will be the one in the group who cleans and lubricates his weapon, even before he eats or sleeps.
The 5.56mm/.223-in. ammunition feeds from a reusable spring-loaded magazine which is loaded from the bottom of the lower receiver/buttstock assembly. Today, thirty-round units are the standard, but twenty-round magazines are also used. The usual load for a Marine might vary from ten to sixteen of these, though the combat vest only has room for six ready thirty-round magazines. To reload empty magazines you take a supply of 5.56mm/.223-in. ammunition (called "ball rounds"), and methodically insert them one after another into the magazine, being careful not to scratch the cartridges or bend the springs. Snap the magazine into the bottom of the M16A2, and you are ready to go.
Firing the M 16A2 is very simple. When you're ready to fire, you pull back the T-shaped cocking handle to load the first round into the chamber. Once this is done, you move the firing selector from the Safety position to either the Semi or Auto positions. At this point, you have a live weapon with a round in the chamber. Take aim on the target and pull the trigger. In the Semi setting, you fire one round for every pull of the trigger. If you are using the Auto setting, the M 16A2 will fire a three-round burst every time you squeeze the trigger. The burst limiter was developed after Army researchers found that accuracy fell off rapidly when more than three shots were fired. Also, the tendency for troops to hold down the trigger in "rock and roll" bursts was wasteful of ammunition. Once a magazine is empty, you push the release button to eject the expended magazine, snap another into its place, and are ready to fire again.
Firing is one thing, but hitting the target is another. The Marine Corps has always prided itself on a tradition of marksmanship, and that tradition continues today with the M16A2. Two new features of the weapon improve its accuracy. The first is a ribbed tubular foregrip (replacing the "Mattel Toy" grips of earlier models). The second is a new sight deck and sight, which makes it easier to put rounds onto a target. You simply turn a dial to the required range setting, align the forward bead with the rear sights, and fire. If you have properly compensated for wind or temperature variations (which they teach you), the rounds should be hitting the targets with regularity. The Corps requires that Marines be able to hit targets with accuracy (50 % or more of the rounds fired for hits) at 200, 300, and 500 yards/ 182.9, 274.3, and 457.25 meters, from a variety of firing position and postures. By comparison, the U.S. Army qualifies basic recruits at 100 yards only. Take it from me. Hitting targets at 100 yards/91.4 meters is easy. Although Marine recruits are taught to fire automatic, three-round bursts, single-shot firing is emphasized. Economy of ammunition is a key factor. When you fire in the burst mode, the muzzle tends to climb up, due to recoil, so only your first and second rounds will usually be on target. One way to avoid this is to steady the weapon against a tree or rock.
The M16A2 is probably the most accurate combat rifle in general service today. In fact, the Army competition shooting team recently moved from the M 14 to a modified M 16. One variant being procured today is the M-4 short-barreled carbine, with a folding stock. This weapon, identical to the M 16A2 in performance, but smaller and lighter, is issued to vehicle and helicopter crews and support and service units, where space and weight are at a premium. The shorter barrel creates louder noise and a slightly different balance. The Marines are procuring over ten thousand of these handy little weapons from Colt. New kinds of ammunition being considered include a tungsten-cored armor piercing 5.56mm/.223-in. round from Sweden. In 1996, the M 16 entered its third decade as the primary combat rifle of the U.S. armed forces. Continuous improvements and variants will keep this classic weapon lethal into the 21st century.