Ha! I‘ve used smg ammo in some HKs without issue so far, which is hotter than anything from Underwood or Buffalo Bore. Toughest guns made from what I’ve found. USP versions (including Expert and Elite and MK23 and USP Compact) but haven’t tried that in P2000s or P30. No issues with thousands of 45super ammo through all HKs in .45No worries. The firearm will let you know when you’ve gone too far.