Gun Trouble
29th December 2014
Not all the problems with the M16 can be blamed on the Army. Buried in the M16’s, and now the M4’s, operating system is a flaw that no amount of militarizing and tinkering has ever erased. Stoner’s gun cycles cartridges from the magazine into the chamber using gas pressure vented off as the bullet passes through the barrel. Gases traveling down a very narrow aluminum tube produce an intense “puff” that throws the bolt assembly to the rear, making the bolt assembly a freely moving object in the body of the rifle. Any dust or dirt or residue from the cartridge might cause the bolt assembly, and thus the rifle, to jam.
In contrast, the Soviet AK-47 cycles rounds using a solid operating rod attached to the bolt assembly. The gas action of the AK-47 throws the rod and the bolt assembly back as one unit, and the solid attachment means that mud or dust will not prevent the gun from functioning. Fearing the deadly consequences of a “failure to feed” in a fight, some top-tier Special Operations units like Delta Force and SEAL Team Six use a more modern and effective rifle with a more reliable operating-rod mechanism. But front-line Army and Marine riflemen still fire weapons much more likely to jam than the AK?47. Failure to feed affects every aspect of a fight. A Russian infantryman can fire about 140 rounds a minute without stopping. The M4 fires at roughly half that rate.
[Modified to remove an embarrassing remark that I ought to have known better than to make. We have good commenters here.]
December 29th, 2014 at 08:08
Both the AR/M4 and the AK are gas operated just different ways of using the vented gas to move the bolt. The AK copies more closely to the venerated M1 Garand. Lots of animation out there showing how each works.
December 29th, 2014 at 10:49
Sorry, Tim, but you’re wrong. The AK is gas operated, not recoil operated. Unlike the M16/M4 rifles, you can actually see the gas tube on an AK.
You can retrofit a gas piston on an M16. (Brownells sells them.) Some of the high quality rifles (FN, usually) that some of our special ops guys use employ a gas piston. That lets the rifle cycle without blowing hot particulates into the chamber.
What makes an AK so reliable is that the parts are fitted with Soviet precision. Everything is so loose that dirt, mud, sand, or carbon don’t affect the mechanism. The down side is that the rifles are not nearly as accurate as the American M16 or M4. The AK was designed to be stamped out cheaply, to be simple enough that any uneducated Third World scum bag could maintain it, and to reliably spray bullets in the general direction of your enemy. In that regard, it succeeded far better than any other weapon in history.
The M16s used in Vietnam suffered with a variety of problems. The barrels were not chrome lined (AK47s were lined), the gas port location and diameter was off, and the powder used in the ammunition put out a lot of hard to remove fouling. The rate of twist was not sufficient to stabilize the bullets, and the bullets were too light. Changes were made and the M4 doesn’t suffer from those issues.
As for rate of fire, the M4 is intended to be used for single shots or 3-round bursts. Running out of ammo is a very bad thing in a firefight. Accurately hitting your opponent and still having ammo when he’s out gives you a much better advantage.
December 29th, 2014 at 16:59
Shows how much *I* know….
December 30th, 2014 at 10:12
“The down side is that the rifles are not nearly as accurate as the American M16 or M4.”
Anecdotally, the last AR I bought was a solid 7 MOA shooter.
December 30th, 2014 at 12:01
Lowly, thanks for the “7 MOA” laugh!!
For those trying to figure that out, the bigger the number, the less accurate the rifle. A really good rifle would be 1/2 MOA. At 7, it qualifies as “spray ‘n pray”.