USP .40 slide problem


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Leitmotif
December 10, 2007, 06:40 AM
I had a small problem with my USP Compact .40 over the weekend. Was out shooting, and the slide for some reason stopped about 7-10mm forward of where it usually does. This was halfway through a magazine. The trigger went sort of loose, and when I checked I pretty much saw something like this:

http://img90.imageshack.us/img90/5739/usplockforwardks6.gif

when I was expecting to see this:

http://img136.imageshack.us/img136/6126/usplocknormalpz0.gif

(Please excuse the terrible line drawings, I didn't take any photos at the range...)

Racking the slide managed to pretty much double-load two rounds. Dropping the mag dropped the second round out, and racking again released the first round. I took off the slide, poked around - nothing obviously wrong. Put the firearm back together, loaded a mag and ran through it at high speed with no problems. Then ran through another slow-fire with no problems. Accuracy wasn't affected.

So, now I'm slightly worried. Any ideas on what could cause this? Have I missed something simple? This USPc has about 2-3k rounds through it. Bought new, never replaced any parts.

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rcmodel
December 10, 2007, 01:45 PM
All right! Fess up!
How much Beer did you drink at the range that day? :D

Seriously, I can't think of a single thing that would allow a short recoil pistol slide to go forward past the lock-up point, except something seriously cracked, broken or bent on the barrel cam, or the cam on the recoil spring guide rod, in the case of the USP.

I would check the guide rod and see if it is bent, and also check the barrel cam for cracks.

At any rate, something is very seriously wrong, and I would stop shooting it until I found out what it is.

http://i81.photobucket.com/albums/j219/rcmodel/KTOG/1224.gif
rcmodel

Leitmotif
December 11, 2007, 03:18 AM
Sigh... I don't drink alcohol. :( Was hoping that it was something simple, seeing as the USP is my only firearm and in my country it's incredibly difficult and time-consuming to get a firearm licensed. Fsck. Looks like I'll be giving up shooting for the foreseeable future.

Thanks for the bad news. ;)

DogBonz
December 11, 2007, 03:47 AM
Have you field stripped the pistol yet?

I just took my USP (45) and tried to replicate your drawing. The only way that I could was by pulling the slide stop almost all the way out. If you have not field stripped the pistol yet, please do so. Check the slide stop (and its shaft) carefully. Make sure that it is intact. Check the slide stop notch on the slide. Make sure that it is not damaged. Is there a possibility that it could have worked loose while you were shooting? Also check the recoil guide rod and the lower lug of the barrel. The only way that the slide can go past battery on a USP is if the slide stop is out of place or the recoil guide somehow popped over the slide stop shaft, or either the recoil spring guide, slide stop, or lower barrel lug is broken.... or it the lower barrel lug somehow skipped over the upper lug of the recoil spring guide....

I don't know what happened, but my USP has over 9,000 rounds with out any issues. The USP design is a rock solid setup, it may have been a freak thing, I don't know, but strip the pistol and check over those parts very well. If they are OK, all is probably well.

Let us know, as I am intrigued to know what caused this.

take care,

-Fred

Leitmotif
December 11, 2007, 04:27 AM
DogBonz:
Thanks for the reply. I did pull the slide off, checked for anything obviously wrong, but haven't field-stripped it fully yet. Will do so tonight and let you know what I find, if anything.

Fairly sure it wasn't the slide stop that came loose - I had to push it out in order to disassemble, and it was pretty well seated. Didn't see anything wrong with the slide stop, slide or the recoil guide, but didn't check the lugs. D'oh. Not seeing anything wrong is why I decided to test the gun after reassembly.

Incidentally, return of the MSPaint:
http://img521.imageshack.us/img521/5213/whatisthiszw5.gif

What is the part circled in red? It's some sort of metal protrusion on the inside left of the frame, just forward of the hammer, and is bent inwards at about a 45 degree angle. (Probably a newb question, but we learn through asking...)

rcmodel
December 11, 2007, 02:06 PM
That is the ejector.

http://i81.photobucket.com/albums/j219/rcmodel/KTOG/1224.gif
rcmodel

DogBonz
December 11, 2007, 04:57 PM
That is the ejector. As the slide moves back, the extractor pulls the empty cartridge out and the ejector kicks it up into the air, clearing the path for the new round in the mag.

Leitmotif
December 12, 2007, 03:07 AM
Fantastic. Thanks, guys. :)

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