USP9 Problem

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echo3mike

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Some tranisitional phase my therapist keeps talkin
I've been dry firing my USP 9F alot. However the hammer has now stopped engaging in DA mode. Let me give you the symptoms as I'm kind of interested in a diagnosis before I send it off to Pacific Blvd.

- In SA mode, the trigger engages the hammer without fail or any notable change in feel, travel or let off.

- In DA mode, there's nothing but slack in the trigger unless I reset the hammer (using a "cocking" like movement of ~ 1/8" until the hammer "clicks")...afterwords, it functions normally for that single trigger pull, but fails to reset. The hammer will wiggle some when the trigger is pressed but doesn't move through it's full range of motion.

I haven't run any rounds through the pistol since this started.

Any ideas?

TIA,
S.
 
First, I don't think this has anything to do with dryfiring.

When did it start?

Do you typically fire DA at the range or only during dryfire practice?

Have you recently fully disassembled your pistol?

It sounds to me like you've got some gunk holding the trigger bar down. Either that or you've broken or lost the trigger bar detent spring.

That spring is pretty sturdy and not under a lot of stress--it's hard for me to imagine it breaking...

I'd get some gun scrubber or Rem-Oil, field strip the pistol and blast away back where the trigger bar goes into the hammer/sear group.
 
I will either send it back to HK if I have a problem...

It would be inadvisable to hold your breath until you hear back from them. I'm not saying their customer service sucks, but... well, yes, actually, I am... :uhoh:
 
Broken/dirty.
Clean the crap out of it.
If it still doesn't work right, send it in.
The sooner you send it out, the sooner you get it back.
 
If you push the trigger forward does it reset?

Clean and lube it, or even just spritz a bit of Rem-Oil or CLP into the action and the trigger bar. If you were firing it, the recoil impulse would knock it past the resistance. I doubt you have any problem.
 
Morgan reminded me of this.
I had the exact same problem with mine.
It wasn't a problem at all, just happened while dry-firing a new gun that hadn't been broken in.
It never happened to me while firing live ammo, it never happened after 500 rounds or so, it never happened when cleaned or lubed, and I think it goes away when sending it to Teddy Jacobsen for an action job. ;)
Matter of fact, it only happened once, after shooting it a few times, not cleaning it at all, and dry-firing the crap out of it.
Clean it up and shoot it, bet it doesn't happen again.
 
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I will either send it back to HK if I have a problem...
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It would be inadvisable to hold your breath until you hear back from them. I'm not saying their customer service sucks, but... well, yes, actually, I am...

wow... what kind of bad experience did you have with HK?

I had a problem with my USP and sent it in and got it back 1 1/2 weeks later and had no problem.

The guy on the phone was respectful and helpful.

The only problem I had was the incompetents working at UPS and FEDEX that freaked out(not really but they were totally incompetent) when I said I needed to send a gun in the mail.

edit: haha its UPS, not USP!
 
Dorian,

wow... what kind of bad experience did you have with HK?

Ten years of bad experiences, too numerous to count.

Currently? My 'smith called HK on Friday morning to get a firing pin safety spring (or will we have to buy the whole assembly?) for a P7 so that it won't slamfire again. Didn't get to speak to anybody other than Robby the Robot, so he left a message.

Still waiting to hear back from them. :uhoh:
 
If you can't correct the problem, I wouldn't hesitate to call H&K. I've dealt with them several times and had quick, polite service. . .

Shake
 
Thanks for the suggestions, gang.

I cleaned it out as best I could (w/ Gun Scrubber)...no difference. Nothing I can do to reset the hammer except for cocking it back a little. From what I can see, all the itty bitty pieces are where they oughtta be and there wasn't anything that fell out IIRC.

The pstol has some miles on it... it's a '94. I haven't detail stirpped it and I'm not really enthusiastic about attempting it (unpleasant experience with my Series 70).

So it looks like a call to Sterling. Fortunately, Sterling, VA is less of a commute than where I work. Maybe I can just "drop it off at the door".

Yeah...I can dream.


Thanks again,
S.
 
You state that you cleaned it - did you shoot some oil into the action and on the trigger bar? If it's dry your problem won't go away.
 
I know USP's very well and hope I can help you. But, I don't really understand your description. Are you just saying that the trigger fails to reset when fired in DA mode, but works perfectly when fired in single action mode?

Also, what variant is it?

Coincidentally, I live near Silver Spring.

Joe Mamma
 
Upon further mucking-around-with-it, it sounds like that's exactly what's happening. Sorry I didn't 'splain it that way. If I go through the process from a "cocked and unlocked" dry fire:

- No noticeable trigger changes, hammer engages...normal process

-Afterwords, trigger slack all the way through the pull, little hammer movement.

Some other item's I've found:

-If I let the trigger fly after I reach the end of a normal pull (total release / finger comes off the trigger w/o follow through), the hammer engages normally / trigger resets consistantly.

- When the triger fails, the trigger bar detent appears to be silghtly depressed... If I cock the hammer back a little bit, the TBD releases slightly ( I don't know if this is causal or mearly syptomatic).

-OCCASIONALLY, the trigger will reset after multiple (slacked) trigger pulls. There's no consistancy with this operation.

Any of this help / make sense?

Thanks,
Scott

P.S. Glad to know another Old Liner!
 
It sounds like it might be the trigger bar loosing proper contact with the trigger bar detent. I don't think the detent is slightly depressed as you describe. I think the trigger bar may be sliding off of the detent so the detent isn't pushing the bar up. But, when you release the trigger hard, the trigger bar gets back on top of the detent.

Also, with the slide off ( * do NOT dry fire the gun with the side off because the hammer flying forward may dammage the gun * ), try pushing down on the disconnector. It only goes down about a quarter inch or so. Does it feel ok? It pushes against the detent spring. You should feel some spring resistance but it should be smooth. Also, with the slide off (and no magazine inserted), push down on the trigger bar where it goes across/beside the magazine well. Does it go up and down smoothly without getting stuck? Actually, the end which attaches to the trigger stays fixed but, the back end (near the hammer and internals) is the part that should move up and down smoothly.

It's really hard for me to imagine exactly what you are describing. But, it's not your fault. I think I'm a little dense and these things are not easily described over the internet.

Echo3mike, what variant do you have? Also, please check your private email.

Joe Mamma
 
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Okay, I understand the problem, and I don't really think you have one - you just don't have it oiled in the right place. The older guns can have this issue in dry fire, but I've never heard of one when firing.

Get some Rem-Oil or equivalent and just spritz the action from the front, the top (down where the hammer axle sits), and the little opening in the back of the hammer when it's down. Get the trigger bar going into the action.

Argh, I wish I was nearer to you to show you - I know how frustrating it can be when your trustworthy partner acts funny. Gunscrubber removes every trace of lube from the internals, and a little fouling makes it worse.

Hopefully my poor description helps, or someone closer can show you.

Let us know...
 
Latest:

It's a Variant 1.

Checked the

-Trigger bar: the rear depresses with a small resistance when it contacts the trigger bar detent but doesn't seem to have any other problem

-The disconnector seems to be a little looser and have a greater range of motion than I can recall when it's pushed down. That range of motion occurs from the normal (?) position all the way down to the frame.

-I don't notice any loss of contact with the trigger bar and the TBD when the pistol functions abnormally.

-Sprayed some CLP in the areas suggested, without any improvement. In frustration, I pretty liberally doused the action in CLP and worked the action several times, again without improvement. At this point, the rapid trigger release failed to reset the trigger and no longer produces the previous result.

One other item I noticed: the hammer strike produces significantly more vibration / looseness in the hammer immediately following the strike than before the problem started.

Oddly enough, the pistol functioned normally yesterday for ~100 trigger pulls. About the time I felt comfortable with the possibility that the pistol self-repaired, I placed a drop of oil in the rear of the hammer around the struts. At this point, the pistol reverted back to the aformentioned failures.




:cuss:




Any other ideas??


Thanks again, gang.

Scott

P.S. Thanks for the offer, Joe. I'll touch base with you when I get off of working nights unless my sleep deprived brain finally snaps and I just send it back to Sterling with a whimper.
 
I'm really out of ideas without seeing the gun.

In defense of Heckler and Koch (Sterling), things have gotten much better with their service recently. I have had to contact them on more than a few occassions. I am not saying they are perfect but, they have been very good to me. The trick is to talk to a person there instead of leaving a message or sending an email.

I just wish there were a way to get factory parts from outside vendors, like with Glock.

Joe Mamma
 
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