Glock 22 owner here. I bought a Storm Lake 9mm conversion barrel for it. Drops right in, no fitting or gunsmithing required.
Add some Glock 17 mags to it and it shoots 9mms just fine. Swaps in and out at the range very easily.
I've never had any problems shooting 40 S&W using the factory barrel. I've never had any problems shooting 9mm from it using the Storm Lake barrel.
So... if it shoots the ammo reliably and accurately, exactly what sort of test am I supposed to run before I trust the barrel? How many flawless rounds are required? 500? 5,000?
So sure, I trust mine with either caliber. I happen to shoot the 40 round fine so that's what's loaded in the gun and it's using the factory barrel. But that's not a matter of trust, just a matter of preference.
The reason I chose Storm Lake over the slightly cheaper Lone Wolf is that I didn't like the black Lone Wolf logo on top of the chamber. The SL is all silver (the logo is engraved, but not painted).