Unless you destroyed the box or lost the receipt, exchange the box of bullets for some .451 Speer Gold Dot HPs or .451 Hornady XTPs. Then buy a 50-pkof short,black Harvester plastic sabots in 45/50 for them. Less than 25 cents per shot.

Hang on to those blue sabots if you have any. Someone on another site is awaiting dies for 40-cal bullets in .399. Could be some for sale next spring.... I dunno just-yet!