Yup, .40S&W to .357Sig just swap out barrels. Rumors have it that the full size usp had reliability issues 40-357. I have not experienced any so far. 9mm barrel swap might cause some reliability issues ie need different mags and recoil spring. You can try to find a 9mm usp slide but it may cost just as much as new usp. Hope this helps.
For some reason the 357 in a full size was a special order item according to HK. I have heard it's easy to swap in the compacts and P2000 series weapons. All that's needed is the different barrel, mags, slide and everything else is the same. I have done this myself with a Sig Factory barrel 357 to 40 and in a Glock with an aftermarket tube 40 to 357. I like the factory components better. Don't know what exactly the problem is with the full size 40 if any, but have heard the same reports from reading other's posting here.
A forum dedicated to and laser-focused on Heckler & Koch firearms, Heckler & Koch accessories and the owners and enthusiasts that love them! Come join the discussion regarding HK pistols, long arms, NFA arms, HK accessories, HK history and trivia and more.