According to some recent U.S. military reports, the most reliable aluminum magazines are Colt/Okay Industries magazines. Okay Industries of New Britain, Conn., has manufactured magazines for Colt since the 1970s. Okay has the capacity to produce more than 140,000 magazines per month, according its last completed government contract. A recent report indicated some other G.I. contractor magazines were failing to meet military specifications and were causing malfunctions because of out-of-specification dimensions and processes. During the early part of the Global War on Terror, the Army stopped shipments into theatres of war all manufacturers’ magazines other than Colt/Okay Industries. Colt/Okay units are identifiable by Okay Industries’ cage code “33710,” which is marked on the lower left side of the magazine body along with the month and year of manufacture. The floorplates are marked either “Colt” or “Okay.” Through the years I have had extensive experience with these magazines and have never had any issues with reliability, so long as they were not abused or left loaded for long periods.
Aluminum magazines may be on their way out of the U.S. military. There has been a requirement to replace them with polymer magazines, and Picatinny Arsenal in New Jersey is working on its own design as well as testing several commercial, off-the-shelf (COTS) magazines. The original 20-round straight magazines are still in production, but these are mainly used by shooters who have difficulty with the longer 30-round magazines when firing rifles from the bench. Additionally, 20-round magazines are well-liked by Special Operations troops with their Mk12 Special Purpose Rifles, as they enable lower prone-position shooting.
Heckler & Koch High-Reliability Magazine
The H&K High-Reliability magazine stemmed from the German company’s attempt to fix the horrendous deficiencies in the British SA80 (L85A1) rifle program—particularly with English-manufactured magazines. The design was carried over to both government and law enforcement sales as an improved magazine for the AR-15 platform and was later used by H&K with its HK416 family of rifles.
The High-Reliability magazine body is made of steel rather than aluminum and is coated with a special maritime finish to keep it from rusting. The coating also has self-lubricating properties in the inside of the magazine to aid feeding. The feed lips have the same strengthened design as the standard G.I. 30-round magazine. The profile of the magazine is somewhat different from a standard U.S. G.I. magazine with two bends. The H&K magazine features a constant curve that allows the cartridges to follow a natural path, increasing reliable feeding of the magazine. The steel follower is 100-percent anti-tilt inside the magazine body.