I have both the USPC in 40 and have an HK USP 357 sig conversion barrel. I think I paid HK $170 ish for the 357 barrel about two plus years ago.
I also picked up the USP 9mm Tactical barrel last year. In a crunch, I would consider it a 9mm barrel I can put in my USP 40. BUT I don't see the point as I LIKE the 40 cal. Always have.
I stock way more 40 than 9... just sayin
I concur, just buy the USP 9 - I have an Expert 9 so I do have 9mm ammo. But not nearly as much 9mm as I have 40. I LIKE the 40. Right now because it's being sold at a discount, mainly because right now there are 20 year old USP 40's that are LEO trade-in's flooding the used market and the prices are way down right now.
The same thing happened when the gun manufacturers starting pushing their 9mm back when the military switched from 45 to 9mm (at the time Beretta won the military contract) and then every other gun manufacturer started pushing the 9mm to LE departments.
It's just cycles of sales and 'popularity' as sold to shooters by gun manufacturers by raising and lower the prices. If 9mm is what you seek, a little patience and constant searching here in the Classifieds and GunBroker should net you a USP 9 with in a month or less.