Eugene Stoner on Small Arms Design—Part 1: Origins of the AR-15

Eugene Stoner designed the ArmaLite AR-10 and AR-15 rifles, the latter of which was developed into the military M16 rifle and M4 carbine. This basic design (U.S. Patent 2,951,424 [PDF]) has been the pattern for a multitude of clone and adapted designs manufactured around the world for half a century.

The AR-15 pioneered the introduction of lightweight, small-calibre, high-velocity infantry weapons. In this video interview, recorded in 1988 by the Smithsonian Institution, Stoner discusses how design of a small calibre weapon was motivated by combat experience in World War II and Korea, where very few combat engagements involved rifle fire beyond 300 metres, and doubling the amount of ammunition an infantryman could carry in the same pack weight was considered more effective than a larger, longer-range round. Stoner goes into great detail about the back-and-forth between arms designers, manufacturers, Defense Department civilian leadership, and Army staff which is involved in the adoption of an innovative weapon. The story of real-world testing of the AR-15 that starts at the 37:00 mark is hilarious and enlightening.

Subsequent parts of the interview will cover the problems introducing the M16 in Vietnam, development of subsequent models, and Stoner’s further work in arms design.

The interview appears to have been recorded on 1980s blur-o-vision video tape, with laughable production values (check out the title cards at the start!), but there is a great deal of history and wisdom to be gleaned here.


In turn, this is the dramatized history of AK-47:


This link should play the whole series (scroll to end of Episode 1 to get Episode 2):


A series on Kalashnikov with multiple Kalashnikov+Stoner episodes:


Weapon function has many nuances that are rarely addressed in “testing”. The M-16 was no different. Stoner talks about the weight savings of the M-16 but fails to speak to the weaknesses of the .223 round.

Ballistic coefficient is a combination of bullet calibre, weight, shape, and velocity. Effectinvness includes things like barrel length, etc. Stoner can speak to theoretical benefits of firing a small bore rifles, but the truth was the M-16 was (and still is) a lousy full-auto rifle. No one that I knew allowed their unit to use the M-16 on full-auto. And nothing compares to a BAR as a full-auto rifle. A LOTof this has to do with the cyclic rate the rifle fires at when full-auto. BAR guns fire about 200-300 RPM. The M-14 and 16’s shoot at 800-1,000 RPM.

Stoner makes it sound like he was the first to use a small calibre rifle for the military. Not true. In WWII The Imperial Japanese infantry used a .25 cal. rifle.

Today no modern quality rifle uses DI for reloading the next shot. They are almost exclusively piston-driven. HK’s (used by the Marines) is piston-driven. The LWRC rifle may be the best AR-style rifle out there today, and it’s piston. Most of the Sigs are piston. So was the old FAL.

Most rifles the military procures today has a forward assist. Usually that just causes the jam to be harder to clear. Last couple ARs I’ve built lately have used uppers without the FA.

Stoner is completely wrong on the question of “cleaning vs corrosive powder”. Marines I saw were constantly cleaning their weapons. Didn’t help much. Barrels and chambers gotten eaten by the calcium preservative. I remember being up on Mutter’s Ridge when the armorer team came to check our company’s rifles. Pretty much everyone’s weapon was found “unserviceable”. They would then replace weapons in groups of 5 or 6 at a time every 3-4 days.