I' M NOT SURE HOW TRUE THIS IS BUT ,

i heard in one of the shooting mags that if you fire .45 colt loads through a .454 revolver chamber , that if enough rounds are fired through it beings that the colt case is shorter than the casull , the colt round can actually cause a throat to start in the chamber , and when the casull rounds are fired the brass casing will expand into the throat and cause difficult unloading of the fired brass.

ONCE AGAIN , I DON' T KNOW HOW TRUTHFUL THAT IS