It should be stated in the manual that came with your Puma, and or a seperate notice to the buyer as to what type ammo to use. the last time I checked the price of 454 casull, it was $100.00 a box of fifty so at $2.00 a round this can get expensive, like Cyrille said you can use the 45 long colt round in the 454 Casull revolver, but it might not work right with the 45 colt in your Puma rifle ( IMHO )
tEN WOLVES