Posted: 7/15/2009 7:03:29 PM EDT
| Ive got an older USP With a lot of rounds through it. Ive put maybe 10-15K through it but I bought it used so who knows. Anyway It has a Failure to extract. a couple times per mag. Ive changed the extractor and spring. Its acts up using old and new HK mags with all kinds of ammo. (WWB, Blazer Brass, S&B, PMC, Magtech). Anything else I should be looking at? Thanks for any help. |
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With that many rounds you may consider the main recoil spring, only the outer one. Wolf sells them and they are not expensive. Get standard power, not extra power. The 9mm has pretty weak ejection anyway in the USP. To remove them I have heard of a neat trick but I have not tried it. Simple unscrew the outer spring over top of the end cap and screw on the new one the same way.
The recoil spring is the only thing I can remotely think of since you have replaced the extractor and spring already. I may be talking out of my butt here so don't take this as gospel, but if the recoil spring is broken or excessively weak then could it be letting the slide unlock too soon before pressures have dropped enough for extraction and the extractor is jumping the rim? I had an AR do this when the gas port was too big from the factory and it was way over gassed, but in the USP I don't see how the recoil spring would regulate unlocking, only how fast the slide travels rearward and returns, but it is a cheap fix to try. A lot cheaper than what I was going to tell you to do, return it to HK for examination, which IMO would be the next step. |
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You should be OK on the FP spring. I see no reason to change it other than you have an extra. I'd leave it alone.
Clean the snot out of the chamber but HKs don't need to be clean to run. That is one of their virtues. I'm afraid I am out of ideas. It may be time for a trip to HK. |