Category: Rifles

Jargon: “AR”–What It Means

Jargon: “AR”–What It Means

Recent events have escalated modern sporting rifles into the national spotlight once again. Although the focus of LNPDSA is pistol training, there is a need to dispel very common misconceptions about the “AR” designation of modern sporting rifles.


To begin, “AR” is the designation the ArmaLite division of Fairchild Engine and Airplane Corporation gave to its rifle line, which began with a modest, bolt action .22 caliber rifle (AR-5) that could be easily taken apart and carried. Its first big brother was the AR-10, a rifle originally designed to compete head-to-head with the current U. S. military service rifle, the M14. The AR-15 was developed after the AR-10 to chamber a round smaller than the then current 7.62 x 51 mm NATO cartridge.

Stock Design

Before we go any farther, let’s take a look at rifle stock design. Typically, rifle stocks were designed to place the rifle’s barrel in the same plane as, and in line with, the shooter’s eye when the stock was placed in the shooter’s shoulder. The rifles of the late ’50s and early ’60s were no different.
Revolutionary War Musket
“Kentucky” flintlock rifle
M1 stock grip and barrel alignment

The AR-10 was a radical departure from the typical design; its barrel and shoulder stock were in line. With the barrel and stock in line with the other, recoil impulse is directed straight into the shoulder. In the typical design, the lowered stock forms a pivot point about which the rifle rotates from the recoil impulse.

However, with a straight-line stock and barrel,  shooting-hand placement becomes an issue, thus the pistol grip. The stock, by virtue of the rifle’s design, became a two-piece arrangement; one behind (the stock) and one in front (the hand-guard) of the action. The straight-line stock and barrel also inhibit a conventional, manual bolt arrangement.
Bolt action

The Fire Selector

So, what differentiates an “assault rifle” (more properly called a military service rifle) from a modern sporting rifle? In a clause, selective fire.
Fire selector on an automatic rifle

The image on the left shows the safety mechanism of an automatic rifle, where the selections are clearly marked “SAFE,” “FIRE,” and “AUTO.” In the “SAFE” position, the fire selector mechanically prevents the fire control mechanism from releasing the hammer. In the “FIRE” position, the fire selector mechanically limits firing to one round (cartridge) with each trigger pull. In other words, to fire a round, the trigger must be pulled, and then released before another round can be fired (semi-automatic fire). In the “AUTO” position, the fire selector limitations are withdrawn, and the rifle can fire multiple rounds with each trigger pull (automatic fire). In the image below, the safety mechanism lacks the “AUTO” selection. NOTE, however, that the absence of “AUTO,” alone, does not make this second rifle incapable of selective fire; there are also internal changes to the action that render the rifle mechanically unable to produce automatic fire.

Fire selector on a semi-automatic rifle

So, back to the original discussion. “AR” is an abbreviation for a rifle design from the Armalite division of Fairchild. It is NOT an abbreviation for “automatic rifle.” It is NOT an abbreviation for “assault rifle.” Furthermore, according to the Civilian Marksmanship Program, the AR-15 isn’t even a “service rifle,” but simply a semi-automatic first cousin. “AR” is simply part of the model designation of designs inaugurated by Armalite, just as Model 700 BDL is the designation for certain Remington rifles, the Model 70 is the designation for certain Winchester rifle designs, and the M&P 15 is the designation for certain Smith & Wesson rifle designs.