I've shot lots of deer with Maxiballs, including the 370 gr/50 cal and the 435 gr/54 cal, both with 100 gr loose Pyrodex. My guns were Renegades with peep sights. Those bullets did exactly what I wanted, passthroughs on all but end to end shots. The deer went down quick and blood trails were always good. I don't know what anyone could find lacking in their performance on deer. I kept shots at less than 100, I think about 80-85 yds was my longest shot.

The 300 gr FPB may be worth a try. They hold together better than PowerBelts from what I hear. I've killed 5 deer with the 350 gr version, all passthroughs with good performance.