"There was a long time member here who was of the firm opinion that the 7.7 Arisaka was so designed that a desperate Jap could stomp the bolt closed on a .30-06 cartridge. The only use I can see for the practice, if at all possible, would be to shoot himself in a losing situation, but there it is; we were told so in any thread of this type."
I went round and round with him a couple of times on that subject.
I can't even imagine how high pressures would run if you were even able to make a stunt like that work. Probably high enough that the bolt would be pretty near impossible to open without something to beat open with.
There's one weapons system in which international ammunition interchangeability was somewhat possible -- the 81mm mortar.
A number of nations, including the US, Germany, and Russia (others, too, IIRC) all adopted a mortar developed in the 1920s and 1930s by the Edgar Brandt Company of France.
All nations made slight modifications to it to suit their own requirements and manufacturing capabilities.
The Soviets increased the bore by nominally 1mm because they had already done a lot of development with 82mm mortars and had lots of that ammo on hand.
But, given the general freebore that a mortar shell normally has in the tube, I think it might be entirely possible for a Soviet 82mm shell to be fired in an American 81mm mortar.
I know the reverse is true.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.