Jim xyz

Hi All, Just wondered on peoples thoughts; if you fire a 21/2 inch cartridge from a gun with a 3 inch chamber will the performance be affected or does it all happen too quickly at that stage? I have a mixture of guns with chambers from 21/2 to 3 inches so just tend to stick to 21/2 inch 30g's for safety. Would there be any noticeable benefit from using cartridges that match the chambers? Many thanks, Jim