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Discussion Starter #1
Fullsize 9mm USP would not eject round with flash suppressor...hmm.

Just took my new fullsize 9mm USP shooting yesterday. Installed a new HK threaded barrel and a flash suppressor. The gun would not eject the rounds with the suprerssor on. As soon as I removed it, the gun fired 107 flawless rounds.

I had the wife with me so I didn't spend any time troubleshooting.

Anyone know what would cause this or had any similar issues?

 

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I'm no expert, but perhaps the weight of the flash suppressor is making it harder for the barrel to tilt up when cycling. This would cause more resistance while the slide is trying to move back and the rounds would not eject properly.
 

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USP .45 tactical pistols have a rubber or teflon o-ring around the end of the barrel to help compensate for the weight and help the slide move back when a suppressor is attached.
 

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The cause is the flash suppressor you are using is too heavy. The lack of an o-ring on the barrel has nothing to do with it. The o-ring has nothing to do with slide function but only serves to help keep consistent slide to barrel lock up and is supposed to improve accuracy. And that is more marketing than reality but the o-ring on the barrel has absolutely nothing to do with compensating for suppressor weight. The USP 9mm has pretty weak ejection to begin with and you put a big old steel flash suppressor on the end and you slow down the slide enough that you can cause malfunctions. Larry at Capital City Firearms use to make flash suppressors of the Vortex design for the USP Tactical pistols. He made them out of steel but when HK introduced the 9SD he found that the old reliable steel Vortex turned the USP into a jam-o-matic. He then started making FS for the 9SD out of Titanium and presto, problem solved. The problem is, nobody I know of is making Titanium flash suppressors of the Vortex design for the 9SD now that Larry has turned his attentions to steel frames for Glock race guns. Finding one is going to be hard and it is going to cost you when you do. I paid $150 IIRC for mine way back when the 9SD first hit the shores and it would take at least twice that now to get me to turn loose of it.
But anyway, that is your problem. You need to get a lighter flash suppressor and your problem will go away.
 

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Discussion Starter #5
USP .45 tactical pistols have a rubber or teflon o-ring around the end of the barrel to help compensate for the weight and help the slide move back when a suppressor is attached.
This has an 'O' ring also. It came with the suppresor.
 

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Discussion Starter #6 (Edited)
The cause is the flash suppressor you are using is too heavy. The USP 9mm has pretty weak ejection to begin with and you put a big old steel flash suppressor on the end and you slow down the slide enough that you can cause malfunctions. Larry at Capital City Firearms use to make flash suppressors of the Vortex design for the USP Tactical pistols. He made them out of steel but when HK introduced the 9SD he found that the old reliable steel Vortex turned the USP into a jam-o-matic. He then started making FS for the 9SD out of Titanium and presto, problem solved. The problem is, nobody I know of is making Titanium flash suppressors of the Vortex design for the (SD now that Larry has turned his attentions to steel frames for Glock race guns. Finding one is going to be hard and it is going to cost you when you do. I paid $150 IIRC for mine way back when the 9SD first hit the shores and it would take at least twice that now to get me to turn loose of it.
But anyway, that is your problem. You need to get a lighter flash suppressor and your problem will go away.
Copy that. Thanks BB. That was a waste of $80.00

What about a CAN? Will that create the same problem?
 

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USP .45 tactical pistols have a rubber or teflon o-ring around the end of the barrel to help compensate for the weight and help the slide move back when a suppressor is attached.
Well he is shooting a USP9 full size. He added a threaded barrel and I don't think those have an o-ring. But I'm still not sure why there would be reliability issues especially since they are meant to be used with suppressors.
 

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Copy that. Thanks BB. That was a waste of $80.00

What about a CAN? Will that create the same problem?
A can would cause additional pressure so perhaps the rounds would cycle reliably. You should look around to see what kind of cans people are running on their USP9's to make sure you don't end up wasting even more money.
 

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No, the can will be OK so long as it has a recoil booster, Neilson device, LID, or whatever they are calling it. Most cans for the USP will include a recoil booster and if you find one that does not, I'd be very leery of that can. The Gemtech Blackside first came without a recoil booster because it was supposed to be light enough, but after a WHOLE lot of people getting them and them not working, Gemtech started including the recoil booster (L.I.D. as they call it) as part of the can for USPs.
I really does not matter whose can you use, just make sure it includes a recoil booster and you will be fine.
Don't quote me on this, but as I recall it the maximum weight you can use a can on the USP .45 WITHOUT a recoil booster is 9 ounces, and that is terribly light, so considering how much lighter it would have to be for the 9SD I'd say a recoil booster is an absolute.
 

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Discussion Starter #10
Does ammo make any difference? I was just using target grade ammo: Remington UMC 115 Gr. MC
 

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What about shooting a hotter NATO style +P+ round with the FH on it? Maybe it would add a bit more speed to the slide? Just a thought ...
 

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Not that I am aware although I'd suspect the heavier bullets would be what you would want to use with a suppressor. A suppressor doesn't do much good if the bullet itself is supersonic so the preferred bullet to use with suppressors is one that is subsonic, which in the 9mm's case, means the heavier weight bullets.

In regards to the FS, then a +P or +P+ load might negate the weight of the FS, but it will also increase wear and tear on your pistol. When I was shooting my 9SD with and without the FS during testing I used a whole range of ammo without malfunctions, but then mine is Titanium. I cannot comment first hand on whether or not a +P or +P+ load would be a sure fire fix in your case with a steel FS.
 

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Discussion Starter #13
Thanks all. I've been kicking around with the idea of getting my Class III so I can sell silencers. I've got a dealer account with YHM and I can get pretty good deals on thier silencers, but I just don't want to pay the ATF $500 a year for the license.

Maybe later on in the year I'll look into buying a silencer and paying the $200 tax stamp.
 

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Greetings, fellow Savannah-area USP enthusiast. I have a USP40 into which I installed a factory threaded O-ring barrel. Without any slide fitting work, the slide would shave the O-ring on one side, meaning the tolerance was too tight. I suspect that you have a similar issue, albeit without the O-ring. I had a local gunsmith buddy (Butch - you may know him) work the slide opening just a tad to not shave the O-ring yet still have phenominal accuracy. I have a CCFA titanium flash suppressor and have never had a problem. I also have an old YHM Cobra 40 and a just newly factory-rebuilt Silencerco Osprey 40 and they both run great.
PM me if you'd like to get in touch with Butch. Hope this helps!
Chase
 
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