I see people talk of being able to shoot a 458 WM in a 458 Lott rifle. Shooting a 375 Holland in a 375 Weatherby. Even a 22 Hornet in a K Hornet. Is this a good thing?

Does the shorter cartridge hurt the original chamber? The shorter shell has more taper so the shell does not sit properly in the chamber. If the cartridge head spaces on the shoulder this is a problem. (3006vs30 Gibbs)

Does the bullet being seated into the normal chamber area hurt the rifle? [ 577 3" vs 577 2 3/4. Lott vs Win Mag]

Any ideas?