I would like to add two things here & you can take them for whatever they seem to be worth to you.
1st, Stan is 100% correct max chamber pressure has virtually nothing to do with the wood cracking. You can quickly look over a loading manual & find 1oz loads @ 1200 fps which have a higher max pressure than other 1Ľoz loads @ 1300 fps. You can fire one round of each from a light weight gun & immediatly & distinctively "FEEL" which one is going to be harder on the wood.
2nd is in regards to the long shell/short chamber aspect. Burrard made this very clear many, many years ago. As Larry pointed out its the pressure the shell is loaded to which is of primary importance. There is however one other aspect which is seldom mentioned & this is the "Loaded" length of the shell. The 25 3/4" hull with a fold/pie crimp applied has approximately the same loaded length as the nominally 2˝" hull with a roll crimp. In either instance there is a space in the chamber beyond the loaded shell so the crimp can open in its intended fashion. To paraphrase Burrard "NO" shell should be fired if the crimp is pushed/forced into the forcing cone, thus placing a restriction on the opening of the crimp.
I believe this would virtually always apply if a 3" shell was fired from the 2˝"/65mm chamber.
Yes, you might do it & not blow up the gun, but "NO" it is not a sound practise.
