Question for all you veteran HK handgun owners- I have fired @ 350-450 rds through my USP 45F and I'm disappointed with the accuracy (I only use factory loads), my Springfield 1911 45 which has the about the number of rounds thru ,it is very accurate and has good tight groups, whats up? what am I doing wrong? any advice or suggestions would greatly appreciated, right now I disappointed with the HK considering the amount of money I paid for it. Thanks.

Take a practical pistol course. It will do wonders for your shooting abilities.

I carried a USP45 for 10 years as a CCW. I shot in IDPA every month and took several classes with it. The thing could shoot better than me - and I shot pretty well, anyway. I shot way better after the class.

USP45 is a great firearm and plan to get another after I get back on my feet. I carry a P220 right now, but looking forward to another USP.

Make sure you have good shooting form and you don't have any bad habits. A class will correct these.

The popular form is Isoscoles and point shooting. It is quicker and will put you in the circle sooner as your sights align.

Go practice and do some dry fire - single action style to help with trigger control.

Good luck.

Quoted: Question for all you veteran HK handgun owners- I have fired @ 350-450 rds through my USP 45F and I'm disappointed with the accuracy (I only use factory loads), my Springfield 1911 45 which has the about the number of rounds thru ,it is very accurate and has good tight groups, whats up? what am I doing wrong? any advice or suggestions would greatly appreciated, right now I disappointed with the HK considering the amount of money I paid for it. Thanks.

Dont be disappointed in the HK.  Its one of the most accurate out of the box .45's in the world.

Get used to the trigger.  Dry fire the hell out of it, and you will improve drastically.

The USP should be significantly more accurate than most 1911s. I suspect your sight alignment or trigger control are the cause. With practice (and remember, only Perfect Practice makes Perfect) you should be able to shoot some tight groups with the HK. From other owners I hear that 2"@25 is easily achievable, and with the factory O-ring barrels or a Bar-Sto barrel, 2" is entirely achievable......at 50 yards.

HK factory sights suck. The rear sight channel is too narrow. The trigger sucks too--when I sold my USP45 to my father he had the trigger slicked up and he's having some Heinie sights installed.

I got TOP GUN at my police academy with the USP .45f. It is more accurate than I could ever be.  Nice to have it in a Bianchi SL321 on my belt.

If you are going to dry fire, get some Snap Caps to protect your firing pin. That is the word over at HKPRO.com

Exactly how are you accuracy testing?  Unless you are shooting with the frame fully supported in front of the trigger guard, using a two-handed hold, and supporting both wrists on sandbags then you are only testing your ability to shoot the handgun accurately, not the accuracy of the handgun.  
If you are doing the above you can expect one to two inch 5-shot groups at 25 yards depending on ammo.  If you are doing the above and are getting 4-5 inch groups while getting small groups with other pistols, then it may be the pistol.  My 9SD has a serious accuracy problem and is the most inaccurate HK I own and the only HK pistol I own where my abilities are greater than the pistol's.  The rest of my HKs, .45 USPs included, are much more accurate than I am.
If you are shooting off-hand and not doing as well as you do with other, more familiar pistols, then just as the others said you need more trigger time behind the USP.  The accuracy is there, you will only need to develope a feel for the USP to achieve it.  It is not your father's 1911.

I have fired all my handguns viced, sand bagged and off hand. I also have a Wilson CQB 1911 and if you are going between a 1911 and USP there are differences but they ain't big. I don't find a difference in POI but I do find myself having to get into the idea of DA / SA with the USP. My "normal" USP 45 Fullsize is capable of 1.5" groups at 25 yards my Expert is capable of 8 shot rag whole at the same distance. Like Big Bore stated it comes down to if the shooter is up to taking advantage of that accuracy.

If I was to make a suggestion:

1. Get snap caps and practice your squeeze with the DA and SA trigger.
(Look for mashing, pushing-pulling, etc... I have found a laser with snap caps works great for this.)

2. Fire from a sandbag or handgun rest first. See where and how your putting them down range from a "controlled" stance.

3. Then move to off hand firing from 3 to 5 yards and work your way out 14 to 25 yards.

Have you tried having someone else try the gun, see if they get the same results?

Also, dry fire the gun & carefully watch the front sight as you pull the trigger, I bet you may not be making the transition from the 1911 trigger to the H&K trigger as smoothly as you would like?

My .o2

The USP has a distinct trigger pull.  Like others said...Dry fire it.  Do it while you watch the news.  Focus on the front sight and slowly pull the trigger back.  Do it like you're trying to pull the trigger without it going off.  It should suprise you when it goes but the gun shouldn't move.  It should stay perfectly still.  

I notice with most people shooting 45 auto,  they tend to scare easily and they form the bad habit of anticipating the recoil.  

So just dry fire without shaking or anticipating.  Rinse and Repeat.