Why is my gun jamming? (H&K USP .40)
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Thread: Why is my gun jamming? (H&K USP .40)

  1. Why is my gun jamming? (H&K USP .40)

    Hey guys, I bought a used H&K USP .40 in seemingly good condition. I took it to the range and put a little over 120 rounds through it and I experianced two jams. Both jams happened as the last round was fed through the magazine into the chamber, Since it jammed both times on the last round, do you think that it could be caused by the magazine spring being to week to push the last round into the chamber?

    If so should I buy a new magazine or just the spring, and where can I buy springs from? Any advice would be great, I'm kinda depressed about the jams , because I just bought this gun and I thought that I would not have this problem with an H&K.

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  3. #2
    The mag is the first thing I would suspect. Can you describe the jam in more detail. Where is the bullet getting stuck?
    "When the outflow exceeds the inflow, the upkeep becomes the downfall"

  4. #3
    from what I hear wolff gun springs are the best. I've bought some in the past and they have worked great. here's a link to their site.
    Wolff Gunsprings - Firearm Springs for Semi-Auto Pistols, Revolvers, Rifles, & Shotguns
    You can have my freedom as soon as I'm done with it!!!

  5. #4
    If you don't mind the 10 round mag, I've found H&K manufactured mags at Cheaper Than Dirt for the USP 40 for $10! These were new, just in the 10 round variety.

    Hey, just out of curiosity, what brand of ammo were you using?
    Blessed be my God, my mountain, who trains me to fight fair and well! Psalm 144 (msg)
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  6. Quote Originally Posted by DarrellM5 View Post
    The mag is the first thing I would suspect. Can you describe the jam in more detail. Where is the bullet getting stuck?
    Well I will try and describe it the best that I can... The bullet was at an upwards angle jammed inbetween the magazine and the chamber with the slide held slightly open from the obstruction, almost as if the bullet was stuck as it made the transition from the magazine to the chamber. This only happened as the last cartridge in the magazine was fed.

    Thanks for the help guys!

  7. Quote Originally Posted by matthewaynelson View Post
    If you don't mind the 10 round mag, I've found H&K manufactured mags at Cheaper Than Dirt for the USP 40 for $10! These were new, just in the 10 round variety.

    Hey, just out of curiosity, what brand of ammo were you using?
    Wow, $10.. I think I'll do that thanks! I was using Winchester FMJ .40 S&W.

  8. #7
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    It may, indeed, be the magazine spring and Wolff is the best. It also may be that the magazine is slipping from the frame. Is it only one magazine or all you have? Whack the bottom of the magazine when you get such a jam and if that clears it it may be the magazine catch on the magazine is worn or the catch itself.

  9. #8
    Quote Originally Posted by kingofthedemo View Post
    ... wow, $10.. I think I'll do that thanks!
    Click here for the direct link. Or, just go to the Cheaper Than Dirt website and search for H&K USP 40 10 round magazine... :)
    Blessed be my God, my mountain, who trains me to fight fair and well! Psalm 144 (msg)
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  10. #9
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    First thing to do when you have feeding problems would be to swap out the magazines. They all might look identical, but you'll be surprised what a tiny defect can do. Be sure to mark your magazines so you'll know that you're actually changing them out. Once you've determined that it's not a magazine problem, then I'd check out the ammo. Different bullet types could be an issue with certain firearms. Many semi-auto pistols develop a "dislike" for certain ammo. It's important to know that whatever ammo you're using feeds smoothly and functions properly in the firearm.

    In your case, it sounds like a problem with the magazine spring. When purchasing a pre-owned firearm, be prepared for all kinds of surprises. If possible, have a competent gunsmith or properly trained armorer examine the pistol. I've seen cases where the wrong spring was used in a magazine. Simple fix for your situation would be to swap out the mags. If this fixes the problem, great. If not, then it would need to be checked out further.

    Good luck!



    gf
    "A few well placed shots with a .22LR is a lot better than a bunch of solid misses with a .44 mag!" Glock Armorer, NRA Chief RSO, Pistol, Rifle, Shotgun, Muzzleloading Rifle, Muzzleloading Shotgun, and Home Firearm Safety Training Counselor

  11. #10
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    Exclamation Change mags

    You have a magazine generated FTF. Dont just change the spring. It could be lip config, follower profile, spring or a combination of the three. Here is how you fix it.

    1. pad the jaws of a shop vice with leather to prevent marring
    2. place the magazine in the vice checking with a square to make sure it is perfectly square
    3. close the vice until the magazine is less than .250 thick
    4. load a new magazine in the weapon and head to the range.

    I suffered a similar issue with a mag for my USP 45. The above sequence fixed it quick fast and in a hurry.

    The padding is not for the magazine but for the vice.

    Never trust a magazine in a combat situation that has given you the least bit of trouble.

    Mags are cheap Life is not!
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    IN OMNIA PARATUS

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