I've always filled up the case with Lil Gun, but never tried the TSX. I will have to give that a whirl.
Gunner's 16 twist may be a fast 16, just enough margin to stabilize the 45 TSX. Those old Winchesters have cut rifling and his could be a hair faster. My otherwise very accurate 16 twist CZ won't stabilize this bullet.
The 45 TSX should work in a 14 twist.
DF
