Isn't there some other modification that has to be made to those guns, other than just chamber lengthening, before they'll handled 2 3/4" shells? Ejection port issues, maybe??

there were something like 6 modifications that had to occur for the longer shells to work properly. chamber, ejection port, and ejector and I can't recall the other 3. I've got Shirley's book and would have to look it up.