BM,
On my Fed papers at 2 3/4" length shooting in a 2 9/16" chamber, I get about 3 loads at about 6500 psi/1150fps and the inside of the crimp area starts to delaminate and loose pieces. I haven't determined if it's from shooting 2 3/4" in a shorter chamber or it's just normal. Some of the guys at the range talked about a hot mandrel to remelt the wax that binds the laminated paper to revitalize the hulls.