Hk usp .45 jamming issue

[Big-bore-bob]

Hi all,
Thanks for the help I know this topic has been discussed before but It doesn't seem like there is a definitive answer. I've been having intermittent jams with my usp 45 expert, and occasionally with my usp 45 standard. I think it's what's called a three point jam (please correct me if im wrong). Round appears to not slide under the extractor properly and requires a palm bump on the back of the slide to send it into battery. Seems to jam on first slide rack mostly, but slide seems sluggish intermittently like its struggles to strip a round from the magazine during firing, there is a cartridge rim wear mark on the extractor face like its snapping over the rim of the round during feeding. Any ideas as to what may cause this? Im trying to not spend a bunch of money chasing parts fixes. I understand extractor or possibly mag spring issues could cause this. Any insight is greatly appreciated! BTW, these jams mostly occurred with hornady HAP reloads at 1.235 coal, however they also occurred with fmj reloads and factory armscor fmj rn ammo 1.25-1.265 coal.

 

[JohnKSa]

Is it possible that the recoil spring needs replacing?

 

[Riomouse911]

First, sounds like springs need to be replaced. They are consumables, like automotive brake pads, so when they get old its a quick fix to swap them out and get back to normal function.

I would go ahead and replace the recoil, magazine and extractor springs. Clean it really well when its apart, lube where needed and give it another run.

If it keeps acting up, then its time to look at the ammo.

Good luck!

Stay safe.

 

[Double_J]

What ammo are you using? About 20 years ago I had a batch of Blazer ammo that was a little lighter than normal and caused some feeding issues with my USP. I agree to swap out springs, Wolff gunsprings makes some good ones for not much money.

 

[Big-bore-bob]

Thanks for the replies, I'll get new mag springs before the end of the month. The standard usp only has 3000 rounds through it, the expert only 1800, figured it was too early for recoil spring swap. I'm using reloaded ammo mabye it's a bit underpowered, usually running approx 800fps.

 

[243winxb]

Seems to jam on first slide rack mostly, *Reloaded Ammo.*

Slingshot it.
2 guns same problem- *Ammo* or running gun dry. Oil them.

 

[Dave DeLaurant]

I would guess this type of malf has to do with too much friction in the feed path and not enough energy in the slide to overcome it.

Possibly a combination of the H&K factory tolerances stacking up at the tight end of the scale, perhaps with ammo a little on the light and fat side?

First of all, does it do this when other experienced shooters fire the gun? My friend Bob developed a similar problem with his well-used SIG-Sauers that we eventually decided was age-related (he just turned 70) limp-wristing on his part. He upped the powder a bit on his economy handloads and put in new recoil springs to introduce more energy into the system and the problem went away. At least for his two SIGs -- he still has this issue with his High Power and .32 Unique. He may be switching to revolvers as primary carry guns in the near future.

Can you replicate the malf by slow cycling using in-spec dummy rounds?

Does the malf occur more with one brand of factory ammo than another? Have you tried hardball +P in the gun?

 

[entropy]

Replace your springs, and while they are out, lightly polish the chamber with a brush wrapped with 0000 steel wool and a little Kroil or 3 in 1.

 

[Tilos]

Thanks for the replies, I'll get new mag springs before the end of the month. The standard usp only has 3000 rounds through it, the expert only 1800, figured it was too early for recoil spring swap. I'm using reloaded ammo mabye it's a bit underpowered, usually running approx 800fps.

OK,
While you have the gun apart plunk test your reloaded ammo and clean the chamber as suggested by @entropy ^^^.
jmo,
.

 

[Big-bore-bob]

While you have the gun apart plunk test your reloaded ammo

Every round gets plunk tested before it goes in the ammo can, this problem seems to be intermittent and I always oil my pistols well. I'm definitely not limp wristing. I could try polishing the chamber, will jb bore paste work for that or does it need to be more abrasive? (I have jb on hand). Thanks for the replies, I can start eliminating variables and find the cause.

 

[Big-bore-bob]

Slingshot it.
2 guns same problem- *Ammo* or running gun dry. Oil them.

I always slingshot my slides. Mabye it's the ammo in those particular guns (tighter tolerances?), all my reloads run perfectly in my sig 1911 and p220. I've reloaded close to 8000 .45 rounds this year, they all shot great. Thanks again for all the suggestions!

 

[entropy]

Every round gets plunk tested before it goes in the ammo can, this problem seems to be intermittent and I always oil my pistols well. I'm definitely not limp wristing. I could try polishing the chamber, will jb bore paste work for that or does it need to be more abrasive? (I have jb on hand). Thanks for the replies, I can start eliminating variables and find the cause.

Start with 0000 steel wool wrapped on a bore brush. If you do use JB Bore paste, use it sparingly and run the drill in shorter intervals, say 10 seconds vs. 30 with 0000 steel wool and Kroil.
Clean out and check often.

 

[5-SHOTS]

I'd try some factory full house ball ammo to see if the problem persists.
I'd check the function of the extractor: it could be too stiff or there's some friction between it and its channel.
If possibile I'd also gently round and polish this two corners (I know it is not a USP breech but I can't find a picture of it...).

 

[243winxb]

intermittent

1. High mileage brass can expand the rim diameter from many firings. It can be measured. All it takes at times is a nick on the edge of the rim.

Some guns (my Gold Cup) are tighter in this area (photo), and will not feed.

2. The extractor can be adjusted so it doesnt make contact with the rim. This allows the case to slide up the bolt face.
Your extractor looks like my s&w 645. I put a shim in, to hold it back more. Fixed my feed problem.

 

[HKGuns]

I'd isolate it in this order.

- Make sure it is clean, including removing the extractor and clean out the gunk that builds up in that channel
- Check your ammo again, run some factory ammo to see if anything changes
- Lube
- Springs

 

[Big-bore-bob]

removing the extractor and clean out the gunk that builds up in that channel

Do I need a new roll pin when I do this? Or can I reuse the old pin?

 

[5-SHOTS]

Do I need a new roll pin when I do this? Or can I reuse the old pin?

When I want to clean inside something difficult to reach, I spray Sonax MoS2Oil to dissolve the dirt and after some minutes I then spray Forch R510 to degrease the Sonax and get all the dirt out in the process. I don't need to take down anything with this method.


A thing I'd check on your pistol is the surface of the breech. Is it flat, smooth and polished or it has some kind of imperfection where the rim can stuck when sliding up?

 

[The Glockodile]

First guess would be the choice of ammunition.

Try “warmer,” reputable ammunition first.

 

[HKGuns]

Do I need a new roll pin when I do this? Or can I reuse the old pin?

It depends on how badly you mangle it getting it out. I have re-used them but I've also had to replace them.

Inexpensive items to keep in stock however.

 

[Big-bore-bob]

Well I just ordered an extractor, 3 roll pins, 2 extractor springs, 2 extractor plugs, and 4 new mag springs. I should be able to narrow down this issue, and have some spare parts for the 2 usp's.

 

[The Glockodile]

Well I just ordered an extractor, 3 roll pins, 2 extractor springs, 2 extractor plugs, and 4 new mag springs. I should be able to narrow down this issue, and have some spare parts for the 2 usp's.

If you were on one of the H&K forums - they’d be attacking your limpwristing and all sorts of presumed deficiencies - on the premise that this great immediate descendant of the Mark 23 can do no wrong

 

[starnbar]

Hi all,
Thanks for the help I know this topic has been discussed before but It doesn't seem like there is a definitive answer. I've been having intermittent jams with my usp 45 expert, and occasionally with my usp 45 standard. I think it's what's called a three point jam (please correct me if im wrong). Round appears to not slide under the extractor properly and requires a palm bump on the back of the slide to send it into battery. Seems to jam on first slide rack mostly, but slide seems sluggish intermittently like its struggles to strip a round from the magazine during firing, there is a cartridge rim wear mark on the extractor face like its snapping over the rim of the round during feeding. Any ideas as to what may cause this? Im trying to not spend a bunch of money chasing parts fixes. I understand extractor or possibly mag spring issues could cause this. Any insight is greatly appreciated! BTW, these jams mostly occurred with hornady HAP reloads at 1.235 coal, however they also occurred with fmj reloads and factory armscor fmj rn ammo 1.25-1.265 coal.

You may have a pistol like mine it will only reliably feed one brand of hardball ammo this it does whether I am shooting a magazine or a box full.

 

[fastbolt]

If one of our guys or gals were to have brought this to me on our range, the first thing I'd do is ask whether the feeding stoppage occurred during live-fire, or only when trying to feed a round by manually retracting and releasing the slide.

Then, the next thing I'd do is grab some fresh American made factory ammunition and watch them load the weapon out on the firing lines. Not fully retracting a slide - or even fully retracting the slide but then slowly releasing or 'easing' the beginning of the slide's run forward - can rob force from the recoil spring being able to slam the slide against the rear of the top round in the magazine.

This presumes a properly cleaned and lubricated weapon, AND a properly cleaned and DRY magazine. Fouled and gummed up magazines can introduce their own frustrating feeding issues. While aging magazine springs can certainly contribute to feeding and functioning issues, that's most often something observed during live-fire. If the top round is being held snugly against the magazine lips during loading of the chamber by manually retracting and releasing the slide, or releasing it via depressing the slide stop, that ought to be good enough for the first round to be successfully stripped from the magazine and both fed up the feed ramp and breech face.

Reloaded ammunition can introduce the potential for case sizing issues that can complicate things, even if the ammunition may not cause an issue in a different pistol. Ditto case rim condition (cut, nicked, rounded off, flattened edges, etc.) Ditto budget factory ammo that's made to low-cost manufacturing specs.

Just some thoughts. Nobody can really diagnose what's happening with your gun, in your hands, using your ammunition, without actually being there to observe you in real time, and examine everything.

 

[JohnKSa]

Well I just ordered an extractor, 3 roll pins, 2 extractor springs, 2 extractor plugs, and 4 new mag springs. I should be able to narrow down this issue, and have some spare parts for the 2 usp's.

To be honest, none of these are likely to be the issue. As an extractor wears, it's less likely to cause feeding problems and more likely to cause extraction problems and anyway, at the round counts you are talking about it's highly unlikely your extractor is worn to the point of causing malfunctions. A really dirty extractor could be an issue, but that doesn't require parts to fix. Mag springs can cause issues, but what you describe doesn't sound like mag springs. In fact, the slide feeling sluggish would probably be helped more with weaker mag springs.

Based on your description of the problem, it's most likely either a weak recoil spring or ammo issues.

 

[fastbolt]

BTW, when I wrote "This presumes a properly cleaned and lubricated weapon", I also meant the extractor's visible hook area - behind/inside of the hook and the breech face next to it - having been properly scrubbed with a stiff nylon, copper, brass or bronze brush, and/or using a slot-tip shaped nylon or brass (no steel) cleaning tool. I try to avoid over-saturating the area behind the hook with excessive solvent or CLP, so it's not carried (along with any fouling) back under the extractor when it's cammed out around a case. I've seen that sort of migrating fouling create extraction issues when it eventually caused congealed fouling to build up between the extractor (behind the hook) and the inside of its recessed slot.