Quick, thanks for the response; and I am by no means being argumentative; but consider the 357 Mag/38 Special scenario. I thought i may have read that as long as the diam. diff. is .005 or less that a cartridge would not rupture. But I have not experimented myself and therefore am asking the more knowledgeable than I.
The length shouldn't come into play (Ex. 38 spec. fired in a 357Mag. chamber). as far as unsafe but could effect accuracy.