What's an AK cook-off?


May 30, 2005, 11:00 PM
I know that too many rounds too quickly can toast a barrell. Does anyone know how this exactly happens with AK47'S?

The Robinson Arms group buy (at the bottom of the THR home page, scroll down :D ) has me thinking about getting one of them VEPR K's (please count me in!).

Talk is it's a heavier barrell with a heavier reciever. Does this mean I can blast a drum of ammo through it with less chance of a cook-off than the junky Norinco's? Is half a drum safe in rapid fire?

The only use for this silly thing would be to repel pirates off the coast of Yemen. :eek:

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May 30, 2005, 11:15 PM
Hm, I've known people that will fire two or three 75 rd drums bump fired and all that happens is the handguards smoke. :evil:

May 30, 2005, 11:19 PM
(Although they may happen around the same time) A cook-off refers to the ignition of a round in a firearm's chamber, not by impact of the firing pin on the primer, but by the residual heat left in the barrel's chamber from a long string of (presumably) full-auto fire.

Having said that, I've gotten the wood handguard and forend on a Norinco AK to smoke pretty heavily after a few drum magazines. No cook-off, and the chrome-lined barrel looked no worse for wear. ;)

May 30, 2005, 11:24 PM
A "cook off" isn't specific to the AK.

It happens when so many rounds have been fired through the gun that the heat transfered to a round that is sitting in the chamber will cause the powder to ignite, and the weapon will fire, "by itself".

It can happen with any autoloading, closed bolt weapon that has fired enough rounds. Automatic rifles like the M60 and 249 solve this problem by firing from an open bolt.

Will the VEPR be less apt to have this happen? Try to think of it in terms of specific heat. The VEPR's heavier barrel heats up more slowly, but also cools down more slowly.

I know from recent personal experience that 150 fast rounds through a VEPR K will:

a) not cause a cookoff (at least within several seconds)
b) might cause a problem with the handguard.

May 31, 2005, 02:56 AM
Bulgarian Arsenal AK's will get so hot after a couple of drums that the barrel will smoke the wood on the shooting bench.

The handguards are some form of polymer so they didn't melt or smoke, but they do get awfully hot too.

If you wipe your AK down with oil after cleaning, the barrel will smoke so bad you will think it's on fire.

No matter how hot any AK I've seen gets cookoff isn't a problem. I have ran many stamped, a couple of milled 16"+ AK's and a krink until they were so hot you couldn't hold on to them with bare hands and still no cookoffs.



Commissar Gribb
May 31, 2005, 03:41 AM
same here.

I've shot my M4 copy and AK enough to make smoke come up from inside the handguards. no "cookoff" so far.

May 31, 2005, 12:32 PM
Open bolt guns will cook off too.

I went to the range with some USMC a few months back and they taught me how to shoot the SAW! They said when you open the top cover, you have to look away for a few seconds while the cool air rushes into the chamber cause if there is a round left in there, it may cook off and blow up in your face. I guess it's a common problem.

I got to shoot about 100 rounds through one though and no probs...

May 31, 2005, 01:08 PM
How can an open bolt gun cook off? The round isn't loaded into the chamber until the trigger is pulled, right? There is no round sitting in the chamber while the gun isn't being fired, is there?

May 31, 2005, 02:28 PM
Maybe because it's belt-fed there is more hot metal around the cartridge, even though it is not chambered.

June 1, 2005, 12:36 AM
An open bolt gun isn't likely to get a cook off unless somehow a round got chambered and didn't fire in an already hot gun requiring the gunner to open the feed cover, clear and reload (belt-fed, crew served).
What you are more likely to get is a runaway gun caused by a worn sear or other mechanical problem. The only remedy is to maintain control of it and interupt the ammo feed. In the case of a belt-fed the AG breaks the belt and on a mag fed gun, hit the magazine release dropping the magazine out of reach of the cycling bolt.

cracked butt
June 1, 2005, 12:45 AM
I don't see a 7.62x39 cooking off too easily unless it is fired off in full auto for several hundred rounds.

An old Marine Korean War Veteran that I hunt with told me that he's seen it happen with the M1 rifle and but he had fired a BAR until the barrel was glowing red and completely shot out and it never cooked off a round for him.
The BAR if I'm not mistaken fires with an open bolt.

The 30-06 produces a whole lot more heat than a 7.62x39 round as well.

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