Ammunition 'cooking off'

[Phaethon]

I went to the range with my stepbrother the other day, and after rattling off a few rounds and handing the rifle to him, he proceeded to shoot the bolt-action single fire; after every shot, he would open the bolt and insert a new round.

I pleaded with him to just load a couple of more into the magazine or use one of the strippers, but he was adamant. He felt that the rifle was getting too hot, and he was afraid of one of the bullets cooking off and firing without him pulling the trigger, or suffering a catastrophic failure in the magazine. I tried to tell him the possibility of it was extraordinarily unlikely, but to be honest I'm not 100% sure myself.

In 90 degree Florida heat, and a gun hot from around 40 .30 cal rounds through the barrel, is there even any remote danger of a round cooking off with a bolt action? I figure that a hot chamber and barrel wouldn't have any effect on the primer all the way at the back, much less the magazine, but I guess you never know.

 

[Busyhands94]

that is highly unlikely, but anything can happen. personally i have had not troubles with any explosive or flammable products during the summer, however it is better safe than sorry.

 

[W.E.G.]

just finished writing about that on another forum

answer is: NO

see http://www.usrifleteams.com/forums/index.php?showtopic=17858&view=findpost&p=165595

 

[homers]

The barrel might get hot but I doubt the magazine would be anywhere near hot enough to "cook one off" otherwise we'd would have heard about incidents already.

 

[Phaethon]

You might want to copy/paste or summarize that post, W.E.G., as I'm not about to make a new account on that forum just for that.

 

[451 Detonics]

By the time the barrel got hot enough to cook off a round the stock would be smoking or melting depending on what it was made of. And if your dad wants to single load then let him...doesn't hurt a thing.

 

[MrCleanOK]

Not hot enough in the barrel, and darned sure not in the magazine.

 

[Frozen North]

I would worry more about being struck by lightning or being attacked by a Sasquatch. If single loading makes him happy, let him single load. It sure isn't gonna hurt anything.

 

[Murphy4570]

Troops fired many millions of rounds through their bolt action magazine fed rifles in the Great War, and WWII. If anything like you are worried about could happen, it already would have about 100 years ago. Your fears are unfounded.

Go out and enjoy the rifle!

 

[Dulvarian]

No concern. In fact, were it I, I'd put a bottle of scotch up as a bet. Nothing like freebies.

 

[WardenWolf]

It can't happen. Not on any carryable firearm, anyway. I've seen videos of someone run his AK until the handguard caught fire, and nothing like this happened. Remember that the new round being loaded is essentially being loaded cold. If this were at all possible, we'd have a LOT of runaway semi-autos due to them overheating, cooking off the round in the chamber, and thus doing a full-auto mag dump. It just does not happen.

Note: the only guns I've ever heard of this being a problem with were the early Soviet ZSU-23 antiaircraft guns. The early models could overheat to the point where new rounds would spontaneously cook off and it would fire uncontrollably. They quickly fixed the problem with additional cooling, though.

 

[451 Detonics]

Actually any belt fed machinegun can easily be gotten hot enough, I have seen barrels glowing cherry red. But even that requires effort and usually several belts fired in a single burst. But the is now way it could ever happen in a bolt gun.

 

[HKGuns]

This just might be the stupidest thing I've ever heard. He obviously knows nothing about firearms.

 

[Zerodefect]

Deosn't really matter as long as the rifle is pointed in a safe direction.

This is why everyone has to lock the action open and empty/clear at NFA shoots before anyone goes down range to check targets.

Still the gun has to get really really hot to cook one off. Unlikely, yes. Plausible, sure.

 

[Vern Humphrey]

Actually any belt fed machinegun can easily be gotten hot enough, I have seen barrels glowing cherry red. But even that requires effort and usually several belts fired in a single burst. But the is now way it could ever happen in a bolt gun.

Except that virtually all belt-fed machineguns fire from an open bolt, so there is no loaded cartridge in the chamber, except for the brief instant when the firing pin is falling.

 

[LHRGunslinger]

Cook off in a bolt action is literally unheard of. You simply can't put enough rounds through it fast enough to cook off. Only weapons I can think of that you can manage a cook off in is a full-auto weapon on an ungodly hot day.

 

[yeti]

I would worry more about being struck by lightning or being attacked by a Sasquatch.

HEY! Hey!...

 

[Sunray]

"...answer is: NO..." A very decided no, at that. Ammunition can cook off in MG's with red hot barrels. Never happen in a bolt action. The ambient temperatures had nothing to do with it.

 

[25cschaefer]

I have seen a few rifles (M16s) cook off in my time in the military; after several hundred rounds on burst or full auto, the hand guards also started to melt. The only time I have seen rounds cook off in a magazine was when I was in an air defense artillery unit; It was an electronic .50 BMG (M3) mounted to the side of an Avenger gun truck. I saw the vehicle commander lube said 50 with WD40, a lot of it too, now these 50 shoot about 75 rounds in 2 seconds and WD40 is flammable but when I told the "master gunner" he told me I did not know anything because I was just a radio operator. When the gunner fired the first burst, the whole side of the turret went up in a brilliant blue ball of fire and about 5 seconds later, POP...Pop Pop... and so on. It was scary because the tubs are fiberglass; after the fire was out and truck inspected, some shells in the ammo can had burst, separated bullet from shell, some pieces (not bullets) actually pierced the ammo can and landed about 20 down the firring line and some were lodged in the tub.

Clearly extraordinary circumstances, now way a bolt gun could do it. (unless you smoked while you lubed it with an extremely flammable solvent).

 

[MrCleanOK]

Vern, M2 fires from a closed bolt. Cooking off rounds is possible.

I have had cook offs with an extremely hot M16, but was using blank ammunition and 3 rd burst. I don't know if repeating the same procedure with live ammo would have changed the outcome.

 

[25cschaefer]

This just might be the stupidest thing I've ever heard. He obviously knows nothing about firearms.

THR?

 

[Slamfire]

Auto Ignition of Black powder 867 F

http://www.ocsresponds.com/ref/msds/msds-bp.pdf

Auto Ignition of smokless is 320 F to 338 F

http://avogadro.chem.iastate.edu/MSDS/smokeless_powder.htm


You would have to raise the temperature of the powder to 320 F, brass is a very good conductor of heat, but still it is inbetween the barrel and the powder.

Someone could calculate how long it would take.

 

[halesb]

THe High Road

This just might be the stupidest thing I've ever heard. He obviously knows nothing about firearms.

Comments like this are why I have 17 posts in 4 years.

 

[Jeremy2171]

Except that virtually all belt-fed machineguns fire from an open bolt, so there is no loaded cartridge in the chamber, except for the brief instant when the firing pin is falling.

Been present for 2 different cookoffs in M240 MGs...and we were wearing them out and they were REAL hot....

No way you will ever get a bolt gun to cook one off in the magazine....

 

[isc]

The stepbrother may not be stupid, but he is certainly ignorant. I would bet my house that you can't make a bolt action fire rapidly enough to cause a cookoff without bending over backwards and doing some pretty contrived safety violations and extra efforts.

I've seen a SAW cook off. The gun had malfunctioned with a round in the chamber (a link was hung up preventing the firing pin from hitting the primer). It cooked off and caused the bullet to squib in the barrel.