Originally Posted by MadMax
Well, wearing out the slide catch isn't really a propane related issue as it's only loaded by the recoil spring instead of the propane blowback.
The safety wearing is also pretty lame. The slide-frame shouldn't have interferences either with duster or propane. Is it possible you got a bad GBB?
Most KSC GBBs seem pretty good. The USP sounds like the first one with chronic issues and actual design flaws. It might actually be a bad build. Their Glocks certainly do better even with propane.
I doubt I got the odd lemon. The safety wearing out is common on all USP Compacts. The problem is legion on Arnie's. I've also seen several broken rear frames here on ASC and locally, because as Myoga fails to realize the rear plastic part that butts up against the hammer mechanism apparently isn't flush with it with respect to the slide rails. As the slide recoils, it catches and rubs on the thin plastic part and stresses it, eventually cracking and breaking it off. Doesn't matter what gas you're using, if it's rubbing and catching it will eventually break.
It seems this gun was built as more of a showpiece than an actual skirmishing weapon, which is too bad because I REALLY liked it. Felt good in the hand, snappy recoil, and relatively reliable. It's too bad they're so plagued with breakage.