The Reliability of the Gas Tube-Driven AR-15/M16/M4 Design is Again Questioned

Several readers wrote to mention these articles: How Reliable is the M16 Rifle? and, a follow-up: The M16 Argument Heats Up, Again. This is sure to raise a ruckus with some of the SurvivalBlog readers that are owners of AR-15s, registered (Class 3) M16s, M4geries, and even AR-10s. Before you send me a fusillade of angry letters, please note that most of the failures mentioned in the After-Action Report (AAR) were with M16s and M4s that had been used in very high volume of fully automatic fire–something that they were not designed to do. (After all these are individual weapons–not crew-served weapons that are designed to be used like garden hoses.) So that is not relevant, in the context of survivalist planning. (If it were relevant, then you ‘d be living through a “worst case” whilst living in the the wrong neighborhood!) Meanwhile, as I mentioned earlier this week in the blog, this report was circulated by a British newspaper, castigating the inconsistent stopping power of 5.56mm NATO: Bullets used by British soldiers ‘too small to defeat Taliban’. (That too, has been debated before in SurvivalBlog, and umpteen other venues.)

Clearly, the Army and Marine Corps could do better for our troops that the current M16/M4 design. Although it would be an expensive thing to do and it would take a bit of a logistics tap dance during the transition, the entire inventory of M16s and M4s could be retrofitted with new gas piston driven uppers for the 6.8mm cartridge. SurvivalBlog’s Editor at Large Mike Williamson notes that the 6.8 cartridge would provide more consistent stopping power, but he sees it more likely to be fielded as the new cartridge for a light machinegun. And I (JWR) believe that regardless of whether or not a caliber change occurs, a gas piston upper should replace the quick-fouling gas tube design that has plagued the M16 and its offspring for more than 40 years. I doubt these either of these changes will be made, since although they are technically the best solutions, the political will and dollars required will be problematic.

Mike Williamson continues: The Brits found out that 7.62mm NATO recoiled too much for full auto, and most of their L1A1s were converted to semiautomatic-only upon being fielded.The 7.62mm NATO is a good cartridge, but it’s too much for an individual full auto weapon.

Along those lines, I believe that the recent Special Ops tests with 6.8mm were in no way related to replacing 5.56. It doesn’t take any field tests at all to determine that 6.8 is a more effective stopper, but not more effective enough to justify the reduced combat load (for the same weight of ammo). Logistically, it is an inferior military round in terms of mass carried for stops made. However, the modular nature of the AR made the tests easy to perform.

I expect that 6.8mm will be the next support weapon and machine gun caliber, given its shorter action length than .308, and its considerable effectiveness. I predict we’re about to witness the end of .30 caliber weapons in the US military.

JWR concludes: I wasn’t surprised to see SOCOM do field tests of the 6.8mm rifles. They are famous for “thinking outside the box”, for “off the shelf” procurement of various goodies, and for adopting different tactics and even different weapons than those used by “The Big Army”. (The SF’s casual term for the balance of the US Army–it’s conventional forces.) Weapons fielding changes for a couple of thousand SF troops can be done fairly rapidly, but fielding a new rifle for the entire US Army isn’t going to happen overnight. That sort of thing takes congressional approval and waiting for slow turning of the gears of the Big Procurement Machine, which from many perspectives is a snail’s pace.