By Walter J. Howe & E.H. Harrison, NRA Staff
First published in The American Rifleman, May 1962
News and publicity releases on a .22 center-fire rifle offered for military purposes, the Armalite AR-15, have raised the question as to whether it should replace the present standard M14 rifle of 7.62 mm NATO caliber. It is not at all impossible to conceive of such a small bore military rifle. The United States Navy rifle was a 6 mm (.236) for a number of years following 1895. Studies were made by most nations, including the United States, of cal. .22 military cartridges, sometimes even smaller. Rifles of cal. 6.5 mm (.256) were adopted by several nations before the beginning of this century. The fact that they were adopted by very few major military powers, and even by those users that were not considered folly successful in the test of World War II, need not prevent renewed consideration of small bores under requirements of the present.
The primary advantage possible with a small bore is lightness of rifle and ammunition, and this is important. A small bore rifle with a given number of rounds of ammunition can weigh materially less than in cal. .30 or 7.62 mm NATO, or for the same weight many more rounds of ammunition can be carried.
Another advantage of the small bore rifle is reduced recoil (though this is less important than formerly, since present gas-operated breech mechanisms make the perceptible recoil much softer than from a hand-operated rifle). Light recoil facilitates training by lessening the shooter’s fear of recoil. It has been hoped, and sometimes stated, that this will be reflected in better shooting and more hits under combat conditions.
Caliber reduction is in line with past development. Adoption of a breech-loading rifle by the United States brought a reduction in caliber from .58 to .50 and then to .45, and adoption of smokeless powder brought a further reduction to .30. Each of these steps was accompanied by a marked increase in effective range and power.
However, further caliber reduction would entail a marked reduction in range and power. It would also change the infantry weapons systems in major respects. This is because a modern system is necessarily composed of a number of weapons which are carefully interrelated.
The development of new weapons concepts is very far from having been neglected. As early as 1952, even before a replacement for the M1 rifle had been developed, thought was given as to what was to follow. This eventually resulted in adoption of the present weapons system of which the M14 rifle is a part. Study was continued, the problem being set up in objective terms of hitting ability, wounding ability, and the load to be carried, regardless of whether the means were conventional or not. Possibly because of some of the means considered, the project was named “Salvo.” We will first note, however, the line of continued caliber reduction, which (despite never having been adopted by our country other than briefly by the Navy) is old and quite conventional.
In 1953 the cal. .30 carbine cartridge was necked to cal. .22 for this purpose at the Aberdeen Proving Ground. Tests were made in carbines barreled and made fully operational with this cartridge. Light weight was fully achieved, but the power was considered insufficient.
The power was then increased, the first step being shortening of the .222 Remington cartridge. This was followed by a whole series of cartridges made from the 7.62 mm NATO, beginning with cal. .22 M1 rifles that were fabricated for these experimental cartridges. The mechanical and tactical performance of the cartridges was carefully tested.
Other investigations were made at the Proving Ground, some going down as far as cal. .18. One investigation was made of a cal. .22 scaled reduction of the well-known cal. .30 M1 ball bullet, which accordingly weighed 68 grs. It was fired at a muzzle velocity of 3400 ft. per second (f.p.s.). The work was done thoroughly. In the design of the barrels for this cartridge, it was determined that satisfactory performance under extreme conditions of ground use required a twist of rifling of 1:8″.
Remington Arms Co., Inc., designed still another .22 cartridge under contract to the Springfield Armory. This, however, was ultimately not used in the rifles which were under consideration for it. Remington then brought out the cartridge in sporting form as the .222 Remington Magnum. In 1957 the Continental Army Command requested two manufacturers to provide new rifles and a new cal. .22 military cartridge. This is entirely in accord with the American tradition of arms development. The great majority of all small arms types since the introduction of the breech-loader in our Army have been designed and supplied by commercial sources. (A long list of these was given in the Question and Answer “U.S. Arms Sources” in The American Rifleman for June 1959.) Some were also sold by the manufacturers to other governmental agencies and to individuals over many years. The cal. .45 M1911 pistol by Colt is one example.
By prompt action of these manufacturers, test quantities of both rifles and ammunition became available in 1957.
One rifle was the product of Winchester-Western Division of Olin Mathieson Chemical Corp., and was called the cal. .224 Winchester lightweight military rifle. While quite conventional, it was a mature and sophisticated design. The parts were few and simple. The cyclic rate of its mechanism was materially lowered by a construction feature for the purpose, which improved greatly the controllability of the rifle in full-automatic fire. A detailed description of this rifle was given in the article “Developments in .22 Military Rifles” in the July 1958 issue of The Rifleman.
The cartridge used in this rifle is the .224 Winchester E2. It fires a 53-gr. flat-base bullet at a stated muzzle velocity of 3300 f.p.s. It differs slightly from the Armalite AR-15 rifle cartridge, which was called at first the .222 Remington Special and now the .223 Remington. The .223 fires a 55-gr. boattail bullet at a stated muzzle velocity of 3265 f .p.s. Both the .224 and the .223 differ slightly in cartridge case from the .222 Remington Magnum commercial cartridge. Their performance is about at the level of the .222 Magnum, which is familiar to shooters.
The AR-15 rifle was developed by the Armalite Division of Fairchild Engine & Airplane Corp., with the great personal interest of its then President, the late Richard S. Boutelle. It is mainly a scaled-down copy of the Fairchild Armalite AR-10 rifle, which had been offered for some years in 7.62 mm NATO and other military calibers. A composite steel-aluminum barrel and a complicated flash suppressor originally used in the AR-10 proved unsuccessful. The AR-15 has an all-steel barrel and a short form of the Army-developed bar-type flash suppressor instead.
Many features of the AR-15 are of European origin and not generally familiar to American shooters, but they were already long tried and have worked out well in this case.
The AR-15 can be hinged open somewhat like a double-barrel shotgun, permitting easy bolt removal and bore inspection. This feature goes back to the Czech ZH or ZB 29 rifle. It will be recognized as a feature of the Fabrique Nationale rifle which has been adopted as standard by Belgium, Great Britain, Canada and Australia. As the T48, the FN was very thoroughly tested by the United States in competition with the Springfield-designed T44, the latter ultimately winning adoption as our M14.
The rear sight of the AR-15 is built into a fixed carrying handle, like that of the British EM 2 rifle which was considered at about the time the 7.62 mm NATO caliber was standardized, and which was even adopted for a short time by Great Britain. The ejection port is covered with a hinged lid, which keeps dirt out of the action and flies open automatically at the first shot as in the German Sturmgewehr 44.
The stock is straight, with separate hand grip. This conformation has been used in many full-automatic shoulder weapons. It brings the recoil force almost in line with the shoulder and thus helps to control the tendency to rise in full-automatic fire. It also adapts well to breech mechanisms which, like the AR-15, have a long receiver and the action spring in the buttstock.
For operation of the breech mechanism, gas is led back from a point about two-thirds up the barrel through a tube above the barrel and within the fore-end. This is much like the Swedish M42 Ljungman rifle, and the later French MAS 1944 and 1949 rifles. A gas-tube system also was used in the Swiss SK-46 rifle. The operating gas is introduced between the two parts of the bolt, forcing the head to unlock and then forcing both parts to the rear.
The gas-tube system obviously eliminates an operating rod or slide and on that account has sometimes been stated to be a material design simplification. However, eliminating the operating slide requires that the bolt be made in two parts, instead of the usual one-piece bolt, so the number of parts remains the same as before. The moving parts must be given a certain mass to carry through the cycle after the initial gas impulse, and elimination of the operating slide requires a correspondingly heavier bolt. Thus both the number of parts and their weight remain substantially the same as in other designs.
Likewise, the extensive use of aluminum has not resulted in an unusually light rifle. The AR-15 weighs nearly 1/2-lb. more than the steel Winchester rifle.
The receiver, including the carrying handle, the trigger guard and the grip, is made of aluminum alloy. The magazine also is made of aluminum alloy, as in a number of other present-day rifles. Aluminum is easily fabricated and can be anodized to a superior non-reflective and durable finish. Necessary strength is provided by a steel barrel extension into which the bolt head locks.
Stocked With Plastic
Fore-end and buttstock are of a light green plastic. This has a pleasing feel and appears to be quite successful. The fore-end stands clear of the barrel and is lined to resist barrel heat. The rear sight is a simple two-leg peep, adjustable laterally. The front sight is adjustable vertically. These adjustments are readily made with a point of a cartridge as the only tool. They are intended for zeroing only. Obviously such sights are not meant for target shooting, but they are reliable in service. Firing trial by The Rifleman staff in 1959 showed the AR-15 to be very easy and pleasant to shoot in semiautomatic fire. The inherently light recoil of the small cartridge is further reduced in effect by the straight stock. Functioning was notably positive, regular and reliable.