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Discussion Starter #1
I have 2 USPc 9mm handguns. I'm having a small problem with one, and a large problem with the other, but it's the same problem with both. I hate to make this too long, but I feel I need to explain what's happening, and how I got here.

The first gun is a BG date code. I bought it used, as a V1. I don't like safeties, and I have shot Sigs for years, so the first thing I did was convert it to a V3. The trigger was not anything close to what I was used to, so I installed the Grayguns short reset kit, and a Wolf 10 pound hammer spring. This made the trigger a whole lot better, and made me happy.

The second gun is a KH date code. I bought it used, and it was a DAO gun with an absolutely terrible trigger. I have converted it to a V3, replaced the old style hammer, and catch with the new style. All the parts were purchased new from HK. I also installed the Wolf 10 pound hammer spring. I have a light FPB spring, and a new style FPB but I have not installed them as a new style firing pin is on order.

Except for the firing pins, FPB, and the Grayguns short reset parts, the guns are the same.

The problem:

The BG gun will have a light strike every once in a while. It might be 50 to 100 rounds before I get one.

The KH gun might have 1 to 3 light strikes per magazine.

Both guns appear to have good solid strikes on the primers. Sometimes the gun will fire on the 2nd or 3rd strike, sometimes it will not fire at all.

Yesterday was the first time I have had them to the gun range. I was using the Winchester White Box 115 gr. 100 round box that Walmart sells. There's a Walmart between home and the gun range, so I usually stop there. I know some people don't like it, but I have fired 1000s of rounds through my Sigs, and never had a problem. I have searched the forum, and I know there are different opinions on the 10 pound hammer springs, so I have 12 pound springs ordered from Wolf to try.

Here's the thing that really puzzles me. After I tear a gun down, I drop an unsharpened pencil, eraser down, in the barrel, and pull the trigger. It's just a feel good thing to let me know things are working. Both of the HKs will launch the pencil. It will clear the barrel by a foot. The Sigs, I never have a problem with, 2 226's, and a 229, won't even raise the pencil 3 inches. It stays in the barrel.

If someone could explain this to me, and maybe tell me something to check, or look for, I would really appreciate it. I would like to be able to carry these guns, but for now neither one is reliable enough.
 

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Plan to buy a USP 9C on hold until I hear the answer to this one......thanks for posting.
 

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Discussion Starter #4
You changed parts and they no longer work? Put the old parts back in. ESPECIALLY for carry guns. You don’t need a target gun trigger for SD.

Yesterday was the first time I have had them to the gun range. If I have to put them back to get them to work, they’ll be for sale. The biggest change I made was the conversion to V3, and the 10 pound hammer spring. That shouldn’t be a problem.
 

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I have two (2) USPc pistols V7 LEM in 9 & 40.

I am a fanboy for the LEM trigger, so as such, I have never felt the need to have any modifications performed. Just run’em as issued.

Never had any of the described issues with either.

I’ve shot enough Win white box to choke a horse. If there were ever a problem w/ dead primer, or other QC problem I cannot recall.

A Gunsmith I patronize uses the pencil test to diagnose light primer strikes as well. If the pencil launches clear of the barrel it has been explained to me, this eliminates the chance of light primer strikes. I won’t say this 100% explains your situation, but it’s as good a test as any.

IIRC you installed some springs etc, or did some modification?
Maybe be worth your time to have a H&K armorer or a g’smith you trust to check your work. We all make mistakes.


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Few points; Winchester white box is notorious for hard primers. Second, Walmart hasn’t sold pistol ammo for several months now, so I would ask how old is the ammo you’re using, age and less than optimal storage conditions can cause primers to be more difficult to ignite. Third, you worked on your gun, and while I’m sure you probably know what your doing, but you may want to have a second set of eyes make sure everything is where it should be, that nothing is binding and that everything is lubed appropriately. Also to that end, you installed a reduced power hammer spring, Wolff as well as any gun manufacturer on the planet warns that reduced power springs can potentially cause reliability issues.
 

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Discussion Starter #8
41magnut, I did install the 10 pound hammer springs, and I realize that might be the problem. I’ve ordered some 12 pound springs to try, and if that fixes things, great. I’d still like to know how both these guns will launch a pencil, and still have light strikes.

jetnspector, the ammo is probably 2 years old at the most. It’s been stored in the house, in a cool dry location. I know the hammer springs could be the issue, but that damn pencil still bothers me.

Thank you both for the replies.
 

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I am gonna have to agree and blame the mods and not the guns... There are numerous combinations of springs to make the USP series have very nice triggers that are 100% reliable. My recommendation would be to go to a 12lb hammer spring and see what happens.
 

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41magnut, I did install the 10 pound hammer springs, and I realize that might be the problem. I’ve ordered some 12 pound springs to try, and if that fixes things, great. I’d still like to know how both these guns will launch a pencil, and still have light strikes.

jetnspector, the ammo is probably 2 years old at the most. It’s been stored in the house, in a cool dry location. I know the hammer springs could be the issue, but that damn pencil still bothers me.

Thank you both for the replies.
I'm sure @41magnut is sorry he mentioned the pencil test now :wink:. His gunsmith is probably old school and lets face it - they don't make pencils like they used to. You need to find a No 2 pencil from 1974 for this test to be accurate.
 

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Just my 2 cents but I installed a Lem on my older USP a while back and was having light primer strikes. Turned out I had the old style hammer strut and that ended up being my problem. After I replaced it with the new style, it ended up fixing my problem. Not sure if this applies to the Uspc.

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My vote is also for the hammer spring. I carry a USPc (although mine is V1 to LEM) about 90% of the time. IIRC 12lb. hammer spring. Stone cold reliable. I have lost count of rounds fired. I work in a dusty environment to boot. No malfunctions of any kind. I have never had more confidence in any other platform for reliability. My suggestion is to install your 12lb. springs and function test. I have no experience with the GG kit. Only one hammer strut for the USPc and 45c If i remember.

If they have not been shot much that would explain alot. They improve greatly after use. I have a full size USP I would put against any standard SIG in terms of trigger "feel". If your looking for way better the match kit can be installed with some mods i believe. There is also a spring chart available on the forum.

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Discussion Starter #13
I'm sure @41magnut is sorry he mentioned the pencil test now :wink:. His gunsmith is probably old school and lets face it - they don't make pencils like they used to. You need to find a No 2 pencil from 1974 for this test to be accurate.

You can do some real magic with a number 2 pencil. The trick is to use a Big Chief tablet.
 

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Discussion Starter #14
Just my 2 cents but I installed a Lem on my older USP a while back and was having light primer strikes. Turned out I had the old style hammer strut and that ended up being my problem. After I replaced it with the new style, it ended up fixing my problem. Not sure if this applies to the Uspc.

Sent from my LM-G710VM using Tapatalk

That came up when I was searching for an answer. I ended up comparing the strut from the BG gun to the strut from the KH gun. They were the same. From the pictures I could find there is quite a bit of difference between the new and old style.
 

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My vote is also for the hammer spring. I carry a USPc (although mine is V1 to LEM) about 90% of the time. IIRC 12lb. hammer spring. Stone cold reliable. I have lost count of rounds fired. I work in a dusty environment to boot. No malfunctions of any kind. I have never had more confidence in any other platform for reliability. My suggestion is to install your 12lb. springs and function test. I have no experience with the GG kit. Only one hammer strut for the USPc and 45c If i remember.

If they have not been shot much that would explain alot. They improve greatly after use. I have a full size USP I would put against any standard SIG in terms of trigger "feel". If your looking for way better the match kit can be installed with some mods i believe. There is also a spring chart available on the forum.

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I’m betting and hoping it’s the hammer spring too. But that damn pencil. I would truly like to know why I can put a pencil in low earth orbit, and not make the gun go bang.
 

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I'm sure @41magnut is sorry he mentioned the pencil test now :wink:. His gunsmith is probably old school and lets face it - they don't make pencils like they used to. You need to find a No 2 pencil from 1974 for this test to be accurate.
I don’t know where to find a date code - but I’m willing to bet I got some @ least that old in the bottom of a drawer or box.


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I don’t know where to find a date code - but I’m willing to bet I got some @ least that old in the bottom of a drawer or box.


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Yeah, if it's a '74, there should be an HE on the metal band just under the eraser - but on the right side. Keep turning it until you find it. :biggrin::biggrin:
 
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