I shoot them in my Pedersoli Kodiak 58 double barrel extremely more accuracy then I have been able to do with round ball in the Kodiak . Also use them in my TC Renegade 54 same results . Havent tried any in 50 cal yet guess I need to order the mold and see.
It looks like .50 caliber? If so, was that the 250 grain REAL bullet or the 320 grain? The 250 did real well in a 1-66" rifle I had; the longer bullet not so good. I suspect that was because the lighter bullet was closer in length to a .490 round ball and the heavier, being longer, needed a faster twist to stabilize.