Barrel heat and warping

Hi,

I read somewhere in passing that tank barrells have a tendancy to change shape when they get hot or cold. Efectivly bend slightly.

This obviously effects accuracy so gunners would during varies points of the day look down the barrel and adjust their sights appropiatly. This ties in with the thread of aiming directly down the barrell.

So presumably this means that with the breach open a gunner can view steight down the barrell.

Has anyone else heard of this affect and practise? Did firing the gun also affect accuracy as the barrels heated through use?

Were differing guns more vulnrable to it? How hot does a main gun get during the day or from firing? I know personal guns get hot from firing but the barrel of a rifle is considerably thinner than a main gun.

Finally did this cause more problems in the north african battles given the greater heats and heat changes from mid night to mid day?

FNG

 

I will mainly depend on
* the length of the barrel
* the metal quality of the barrel
* the weight of the shell
* the speed of the shell when fired

The faster and heavier the shell is, the more heat will be generated. The If the barrel is also long, or have a muzzle brake, it will be more likely to bend, because of the weight. A soft steel type will also be more likely to bend.

After the war, the Danish army tested the MG 42. In one experiment, 5,000 rounds were fired in immidiate succession, by connecting the individual ammunition belts to create one long belt.
The MG 42 fired all the rounds without any problems, but when the last round had been fired, the barrel collapsed completely, like a wet macaroni. The only thing keeping it up was the rapid fire of the machine gun.

 

I've heard of barrel bend. I've read that there was alot of work done post WW2 in relation to it. Probably was huge problem up to mid to late WW2 since gun barrels were shorter and ammo loads bigger.

As for looking down the barrel to detect bend that probably won't cut it. We're talking about a very shallow bend.

 

IIRC this is why most modern MBTs have thermal sleeves on their barrels, to reduce the effects of high & low temperatures. They also tend to have a wee laser thingy that tells the firing computer what shape the barrel is in (quite literally...)

 

Sounds very wish I could have been there 60 years ago when they did it. Seriously the barrel was being kept up by the bullets? Sounds unfreaking beleivable.