GregSY, I would not do it except in an emergency. A 22 short can be fired in a longer chamber because the bullet is the same dia. as the outside of the case. However in the case of the 4570- in a 45-90 the chamber ahead of the bullet will be larger than the bullet in dia.allowing the bullet to yaw and obturate filling the chamber only to enter the rifling about .040 oversize in dia. Be safe and use the right cartridge. Rich