Underhand technique

[wobbler]

I've bent a few yellows, 2 blues, a 5.5x7 crs and a 1/4×7 hex, so not much experience at all.

Very end of the second hit, twisting wrists inward, is that bad? Tweaked something on the top/back of my left hand, and I'm not sure if it's from that or from trying to crush .302x7 overhand and getting stuck at 90* (did both same day.)