USP 45 not holding open

[Alpha_Mutt]

I picked up an almost new looking full size USP 45 this weekend. Stainless, date code AB, with 2 10-round mags. Great gun but it does not hold open after the last round. It does this with both mags. Is this likely a mag-spring problem or something else?

[Ninjamaster]

My 2 10 round mags with finger extensions do not hold open the slide after last round. My 2 10 round flat floor plate mags hold open the slide. Don't know why though. Spring issue probably.

[TheAutomator]

Mag springs. Get some springs from Wolff, the +10% power ones.

http://www.gunsprings.com

[kell211]

Mine had the same problem, new wolff springs cured it right up.

[svddragunov]

Not trying to call you out, but limp wristing can also cause a failure to lock back.

[Ninjamaster]

I guarantee I gripped my 45 the same everytime and only the extended mags didn't hold open the slide. The gun is used but the ext mags don't have much markings on them as compared to the flate base mags with some markings but the flat mags hold open the slide everytime.

[scarface]

I just had a similar problem with my USP and it's jet funnel mags. After a good cleaning and some testing I realized it was a spring problem. So, I stretched the spring a little bit and put the Mag back together. After the stretch the Mag is now locking the slide back. We'll see how long it works for and in the meantime I'm looking for new springs.

[Alpha_Mutt]

I don't take offense at the limp-wrist suggestion, I am sure it happens. It also seems to be offered as the cause for most malfs -- ftf, fte, hold-open. However I shoot a lot and I don't think I suddenly went limp because I had a new (to me) gun. I have also tried limp-wrist shooting, right up to the point of being unsafe, and have never found that it consistently produced functioning problems.

Wolff springs it is. Thanks.

[PHARO]

My usp 9mm did that once, replaced the mag spring and it fixed it

[MrShipwreck]

HK factory mag springs just don't seem to cut it. I have 6 USPc mags - I've had to replace the spring in every one of them with the +10% springs - work fine afterwards

[softmentor]

I cought some vid. on Fireingline of someone trying to limp wrist and he could not produce any failers. Just for jollies I tried a few rounds with the limpest grip I could safely hold my USP .45 with and I could not get the gun to fail, including lock back. Frankly, I now believe the "limp wrist problem" is a falicy.

[amstaffHK]

It ejects the shell but doesnt lock back? thats odd.

[Litigator123]

I reported this previously with my new HK45 and was told it was my grip etc. I still have yet to do a full investigation on the matter.

[smschulz]

Not trying to call you out, but limp wristing can also cause a failure to lock back.

This is usually the first comment of someone that has no idea what they are talking about.

[nwusp45]

It is very easy; if you are right handed, to find your thumb just slightly resting on the ledge of the slide release. Afterall, that thing is HUGE. I had mine shaved down a few years ago and no issues since. Just a thought-good luck.