Most modern guns can handle minor use of the +P and +P ammunition, but you don't want to feed a steady diet of the stuff in the gun. If you look in the USP manual on Pg21 you'll see that +P and +P+ are approved for use in the USP however increased usage = increased rate of wear and tear.

VAMarine, Thanks for the information ...

I bought a box of the +P+ ammo without thinking about which firearm I could use it in.

You can use it but it is not good for the internals. This type of ammo however should mainly be used for defense... if you do have to use it then better to ruin your handgun than not be able to defend yourself. Not that a couple magazines would be likely to do any damage.

If any gun can take it the HK will,but I wouldn't make a habit of it like said.I know it was an accident here but if I felt the need at all to think I needed +P i'd rethink my choice of cartrige.

HKs can take it easily. I would become proficient with +P+ ammo and carry it, but once that's done, I'd shoot plinkin' rounds (WWBox, FMJ, etc.) just to not put the wear on it. I doubt I could wear out an HK in my lifetime but it never hurts to go easy on it when you can. Just my two bits.
Charlie

LOLOLOLOL---Uh...yeah, I think they can handle it. It's an HK boy, not a piece of Tiffany flat wear!

While the USP isn't as robust as the MK23,this will tell you how strong this thing is.In testing the MK23,it ate 6K proof rounds (basically a +P+++,a box of these can destroy a piece) and then ate over 30K +Ps with no appreciable wear,impressive is an understatement.USPs are little tanks,a small version of the MK23.

In a word yes, but still wondering why anyone would want to .....JJ

Why not just get the HK in 40 S&W? The size is the same. It'll beat 9 mm +P++.

This type of ammo however should mainly be used for defense... if you do have to use it then better to ruin your handgun than not be able to defend yourself.

As I understand it HK did extensive testing on the USP 9...of coarse they do extensive testing on all their guns but the USP 9mm was tested with +P+++ for 30,000 and never had a hiccup...The USP is built like a tank...I have the full size and it`s had thousands of rounds through it and it has never failed once...It`s a joy to shoot with the reduced recoil...I have sold all my other 9mm`s [ even my Glock ]...The USP is the best out there....Jim

Pretty sure it would handle a 20mm round if u could get it in there. like everyone said, shoot it, just preferably not thousands of rounds of it.

Well, I bought my first USPf 9mm in early 1994---right after they came out---I had been carrying a Browning P35 C&L, but my boss decided that we could no longer carry SA pistols after a home-gunsmithed 1911 went off in the store (no one hurt). The only DA/SA pistol I owned at the time was a Walther P5 9mm, so I carried that briefly until I handled a USP---I bought that pistol and still have it. It became my "daily-driver" and I cannot even guess how many rounds went thru that pistol (incliding +P & +P+). Never missed a beat---thats right NEVER!! Now I favor my P2000 9mm---smaller and lighter, and it has never failed to feed, fire or eject either! My orig USPf is carefully hidden next to the bed---my P2000 and USPc 9mm are for carry/field use. Use and enjoy!

Speaking of the P30...are they appreciably smaller than the USP? I shot a USP lately, loved it, but it is just too big for my hands. Is the P30 a better fit for smaller hands? I know the correct answer is to go handle one, but before I spend the time and energy, I thought I'd ask...thanks.

Yes, the P30 is noticeably smaller than the USPf and just a tad bigger than a P2000. The grip system is like no other that I'm aware of---changeable in so many ways! I have large hands, but prefer the pistol the way it came out of the box with the grip parts marked S (small)---my wife also likes the feel of this gun. The way it's working out now is the full-size pistols have become "house guns"---the smaller guns (P2000, P30, USPc) are the outdoor guns---smaller, lighter, generally easier to pack without really giving up any of the usefulness of a larger pistola. Warning; HKs are addictive, you could find yourself with several---ask me how I know...

The USPf is a large gun,I only carry DA if it carried appendix.Look at the USPc if you want the 45.

The USP was designed as a .40 pistol so it is over built as a 9mm. As lomg as you don't abuse it, +p or +p+ will not hurt it.