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View Full Version : HK USP 45..Slide won't lock back on last shot


neomedic
07-31-2011, 10:12 PM
Hey All,

I was shooting the HK Fullsize USP .45

The slide won't lock back on last shot. So I made sure I wasn't limp wristing. That wasn't the problem. Then I thought I was riding high and was pushing down the slide release. I made sure my thumbs was not near the slide release. That mostly work while I was shooting. It would lock back on last shot.

But after wards when I was playing with slide (just racking it with an empty magazine)....I found out that when I pull the slide / rack the slide, the slide release would not "spring" up to catch the frame to keep it open. I tried different magazines, some would push up the slide release up to the frame better than others, but none did it convincingly.

Is there a "spring" for the slide release that I can change? Or any other springs I can change? I was going to clean and lube everything and take it back to range to see if anything changes. What else can I do?

Or should I send it back to HK?

Thanks

sirgiles
07-31-2011, 10:38 PM
how old are your mags?
changing the springs solved the same issues i had.

dvsdev
07-31-2011, 11:50 PM
The first thing I would check is the magazine spring. USP magazines are notorious for weak springs. Try a fresh magazine with a fresh spring and see if the problem still persists. If that fixed the problem, you need to replace the spring in the used magazine. An alternative is to take the old spring and stretch it out.

dvsdev
07-31-2011, 11:52 PM
I just re-read your post. Try stretching the magazine springs in the mags that don't lock the slide back.

neomedic
08-01-2011, 5:09 AM
The magazines are all genuine HK mags. Both are the originally supplied with the gun (about 10 years old). But not shot much...mags probably seen 500 rounds max in the 10 years. Gun is also the same round count.

I will try to post some pic and video later today.

So as I understand it, there is a spring to pop the slide release down when there is no magazine in the gun. and that the magazine is the one that physically pushes up the slide release to hold slide back on last round????

If that is the case, then it might be my magazines. Will try to get new HK mag today. Any one know of a good place in Los Angeles/ San Gabriel to get one for a good price?

Thanks.

Webologist
08-01-2011, 5:23 AM
The magazines are all genuine HK mags. Both are the originally supplied with the gun (about 10 years old). But not shot much...mags probably seen 500 rounds max in the 10 years. Gun is also the same round count.

I will try to post some pic and video later today.

So as I understand it, there is a spring to pop the slide release down when there is no magazine in the gun. and that the magazine is the one that physically pushes up the slide release to hold slide back on last round????

If that is the case, then it might be my magazines. Will try to get new HK mag today. Any one know of a good place in Los Angeles/ San Gabriel to get one for a good price?

Thanks.

Agree with others. Get new Wolff Magazine springs to resolve this issue.

Regards,
-w

neomedic
08-01-2011, 5:31 AM
Was looking at the HK part list:
Shaped spring (slide release) 21417 What is that part used for?

Also, anyone know of a vendor that sells HK parts in So. California. Would like to get the parts today to figure out what is going on vs. ordering online.

Thanks.

neomedic
08-01-2011, 7:03 AM
Ok...so I ordered some wolff magazine springs and a new HK slide release.

Hope that will help.

Pics to follow when I get home to take some.

neomedic
08-01-2011, 2:04 PM
I went and borrowed a new HK USP magazine and when rack the slide, the slide release will fully engage the frame:

https://lh6.googleusercontent.com/-4HHph-BOS3M/TjcgqjBwtDI/AAAAAAAAAfQ/s8sJzzXQ0hI/s640/2011-08-01%25252014.44.02.jpg

With my old magazines, the slide release will usually not engage the frame enough to lock the slide back. And when it does, it barely does it:
https://lh5.googleusercontent.com/-xy8yUGAI6DY/TjcgZ6QGTdI/AAAAAAAAAfU/mb-xD9CA4c8/s720/2011-08-01%25252014.43.42.jpg


So it looks the springs in the magazine needs to be replace. I ordered some wolff springs and when they get here, will go out to the range and see if it still is a problem.

neomedic
08-01-2011, 2:14 PM
By the way...I'm still pretty amazed how accurate the HK USP is for a combat trigger. This was shot free hand SA at about 7-8 yards. 10 shot group.

https://lh5.googleusercontent.com/-RAHs34oUV8w/Tjchgu5rEcI/AAAAAAAAAfY/zDHZaGkVBC8/s512/2011-08-01%25252014.49.15.jpg

https://lh3.googleusercontent.com/-xc7kEH5uox4/Tjci_LV7LxI/AAAAAAAAAfc/iERZ-VmVMfw/s512/2011-08-01%25252014.50.02.jpg

dvsdev
08-01-2011, 2:24 PM
Out of all of my handguns, I am most accurate with the HK USP 45. I don't know why?!

neomedic
08-01-2011, 5:29 PM
I noticed the slide release being out of shape too. I ordered a new one from HK. So when the new slide release and new wolff magazine springs come, I'll head out to the range and see if that fixed the problem.

KIDRR
08-01-2011, 5:48 PM
Same thing happened to me on my USP 45. It turned out to be one weak magazine, the rest it functions perfectly with. You'd think with the prices HK charges for magazines they'd hold up longer. :rolleyes:

223Dude
08-01-2011, 6:57 PM
I just re-read your post. Try stretching the magazine springs in the mags that don't lock the slide back.

I had to do this too after having my magazines loaded for 6 months. It worked! The OEM springs really are kind of weak in my experience.

sirgiles
08-01-2011, 7:23 PM
I noticed the slide release being out of shape too. I ordered a new one from HK. So when the new slide release and new wolff magazine springs come, I'll head out to the range and see if that fixed the problem.

actually, your slide release is in better shape than mine and it still keeps going and going and going...

Sniper3142
08-01-2011, 9:38 PM
I'm very surprised to hear these reports of older USPs and magazines having problems.

One of my USP45fs is 14 years old (KF Date Code - bought in 1995) and hasn't needed any work. She's got over 18,000 rounds thru her (at least) and is still going strong (but could probably use a new recoil spring). I've also got original magazine purchased at the same time that haven't needed any work either (they are so old that instead of saying "US Pat 5 568.696", they say "Pat Pend."!).

The mags continue to fully engage the Slide Lock with no issues. ;)

Here are some pics:

http://img.photobucket.com/albums/v499/Snape315/Boom%20Sticks/USP45FullsizeSlideLock.jpg

http://img.photobucket.com/albums/v499/Snape315/Boom%20Sticks/USP45FullsizeMagazine.jpg

Chief-7700
08-01-2011, 9:44 PM
I went and borrowed a new HK USP magazine and when rack the slide, the slide release will fully engage the frame:

https://lh6.googleusercontent.com/-4HHph-BOS3M/TjcgqjBwtDI/AAAAAAAAAfQ/s8sJzzXQ0hI/s640/2011-08-01%25252014.44.02.jpg

With my old magazines, the slide release will usually not engage the frame enough to lock the slide back. And when it does, it barely does it:
https://lh5.googleusercontent.com/-xy8yUGAI6DY/TjcgZ6QGTdI/AAAAAAAAAfU/mb-xD9CA4c8/s720/2011-08-01%25252014.43.42.jpg


So it looks the springs in the magazine needs to be replace. I ordered some wolff springs and when they get here, will go out to the range and see if it still is a problem.

Guess you found the problem! Slide not locked back on the last round usually get traced back to a weak magazine spring.

neomedic
08-02-2011, 7:29 AM
Haven't changed ammo, mostly use 230 grain ball for target shooting. Ranges from Winchester White box to Federal Eagle.

Could the damage to the slide release be caused by the magazine only barely pushing up the slide release, so the slide just "runs" over the tip of the slide release? Does that make sense?

Ubermcoupe
08-02-2011, 11:06 AM
Did you have the magazines loaded that whole ten years? Even though the use of them was little the magazines may have lost their touch if they were kept loaded.

Glad you found the likely culprit. Hope the Wolf springs resolve the issue permenately. :thumbsup:

neomedic
08-02-2011, 11:27 AM
Yes, the two mags where loaded most of the time. It's my go to gun.

Was at the range the other day, even the though the magazines had issues and slide won't lock back, the 100 rounds that I shot was flawless. Don't remember exact round count, but >500 for this pistol and 0 issues (ball and JHP) :D

RippSpeed
08-02-2011, 6:50 PM
This has happen to me... all I did was replace the magazine followers. if its not the magazine follower its your slide release spring or the slide stop it self might be worn down....

can you take pics of the magazine followers ??? theres a little tab that might have been damage or worn that it wont activate the slide stop.

neomedic
08-02-2011, 8:52 PM
The followers don't look too bad. There is a small notch on the follower where it would push the slide release up. But I think it's just normal wear and tear from plastic push a metal object. The notch is not deep at all.

https://lh6.googleusercontent.com/-W74iBGsmS44/TjjQ83qCDpI/AAAAAAAAAf0/IwVu7zM4a_E/s640/2011-08-02%25252021.37.26.jpg

https://lh4.googleusercontent.com/-Fa66B5iNsIM/TjjT3vwdEfI/AAAAAAAAAgA/5bttP4xgbeg/s640/2011-08-02%25252021.36.57.jpg

RippSpeed
08-02-2011, 9:11 PM
The followers don't look too bad. There is a small notch on the follower where it would push the slide release up. But I think it's just normal wear and tear from plastic push a metal object. The notch is not deep at all.

https://lh6.googleusercontent.com/-W74iBGsmS44/TjjQ83qCDpI/AAAAAAAAAf0/IwVu7zM4a_E/s640/2011-08-02%25252021.37.26.jpg

https://lh4.googleusercontent.com/-Fa66B5iNsIM/TjjT3vwdEfI/AAAAAAAAAgA/5bttP4xgbeg/s640/2011-08-02%25252021.36.57.jpg

Ok can you take a pic of the little knob on the slide stop ??? See if there's any worn down metal on it ???

I've had this problem with a couple of my mags I bought used... Do this test for me... with an empty mag insert into the pistol and rack the slide... does it lock ???

Like I said only 3 things can be wrong... From the easiest to the hardest...
1)Followers
2)Slide release is worn
3) Slide release spring needs to be replaced

P.s. can't be your springs because if it was ... Then you would have feeding issues, which you stated you don't...

RippSpeed
08-02-2011, 9:26 PM
https://lh5.googleusercontent.com/-xy8yUGAI6DY/TjcgZ6QGTdI/AAAAAAAAAfU/mb-xD9CA4c8/s720/2011-08-01%25252014.43.42.jpg



After seeing this pic its definitely your follower... Not your springs .... as I said before if it was your springs you would have feeding issues.

To test if its your spring ... load a mag to capacity and manually pull each round out ... If the next round pops up with some force then its not your spring... Another way to test your springs are to load mags to capacity and manually cycle it thru the pistol by racking the slide back and forth till the last round ... if they all get ejected out then definitely ain't your spring...

P.s. good luck brotha...

starsnuffer
08-03-2011, 9:34 AM
I've had this issue on my USP compact .40 when using weaker then normal ammp (USA new brass ammo). Switching back to lawman or federal solved the problem immediately.

-W

jyo
08-03-2011, 10:01 AM
I own an HK USPf 45 and can say that your problem is caused by weak magazine springs---this is a known issue with HK USPf 45s---replace with Wolff springs---problem will disappear! Now go out and enjoy shooting one of the finest pistols you can buy.