First shooting 40 you need 165, or 155 gr bullets to get powder to make lots of gas,Only problem is mag capacity 24 versus 30 makes a difference.
recoil still felt but not as bad.
sti dvc mine shoots long ammo fine, have been told by shooters that had tnem that they will crack.
recoil not as bad as 40 to me.
next match you can try mine.