HK USP Barrel Swap

K

Kevinfreem

New member
Hey guys. One of my dream guns has been an HK USP in .45. Wife of the year bought me one for birthday and mentioned that the barrel could be swapped out for a .40 S&W barrel and the gun could switch to .40 easily. I was not aware of this but Im a bit leery of just ordering one. There is not a lot of information online about switching like that so I was wondering if anyone has done this before or has similar experience. Does it require different magazines as well? I wouldnt mind switching them out as I love shooting .40 as well but I dont know if i want to pull the trigger so to speak without knowing what might happen to the gun as a result.
 
No sir. In fact I haven't been able to find it online. That's what made me think the salesman may have been shooting his mouth off.
 
"...the gun could switch to .40 easily..." You'd need a new slide too. Rim diameter is 56 thou smaller on the .40. And 36 for the case body at the head. Plus different mags.
Far more likely that it'd be less fuss to buy a whole .40 &W.
 
USP 45 to 40 isn't really going to happen. They make 9mm kits (slide, barrel, spring and mag) that can be mounted on 45 frames, but they're only readily available in Europe. It's not an easy gun to do any caliber swaps on.
 
There were some HK models that could swap between .40 and .357Sig but I've never heard of .40 and .45 being interchangeable.
 
The three HK models that came in 357 SIG (USP Compact, P2000 and P2000SK) could all be changed to 40 with just a barrel swap, it's one of the features of that caliber since they're closely related.

45 to 40 though you run into issues with almost every part involved: mags, magwell, breechface, extractor, barrel (in many aspects beyond the bore diameter), springs, potentially simple geometry, it just goes on.
 
Can a USP 40 be converted to .357 SIG by simply switching the barrel? Will the magazines interchange?
As to the op's question, T. O'Heir is probably right: best to just invest in a pistol already chambered in .40 rather than trying to convert a USP 45 to handle the forty.
 
Try a different hammer spring. Wolff sells them or you can go the full match trigger route from hkparts or HK US directly (plenty of guides on the install).
 
dgludwig said:
Can a USP 40 be converted to .357 SIG by simply switching the barrel? Will the magazines interchange?
Click to expand...

I don't think anyone makes a drop-in 357 SIG barrel, but otherwise it should work in theory. However, HK themselves tried to make a FS USP in that caliber and couldn't get it running to their (high) standards of reliability, so there may be something about the design of the full-size USP that doesn't work well with that round. (That said, I have a Compact in 357 SIG that is flawless.)
 
You must log in or register to reply here.
Back
Top