Umarex (KWA) USP full size problem

Bemused

Hey all,

Just wondering if people with the gun in the title can give me some feedback to see if the problems I am experiencing are unique to my gun or are a general issue.

When I first got this I was very unimpressed with the performance. The slide would not come all the way back after a couple of shots and therefore it would not load the next bb. If I warmed up the magazine every couple of shots the slide would lock back. This was during the cold "snap" though and I thought things might improve around now.

It's still pretty poor and any kind of rapid fire will lead to difficulties with slide movement. This makes it pretty much unskirmishable.

These are the "new" magazines btw with the improved gas efficiency (lol).

Any experience and advice welcome.

CpcRc

Have you lubricated the rails on the slide and lower frame?
Have you lubricated the internals with silicon oil for smoother action on the trigger?
Also when you lock the slide back, there should be a screw on the top slide when you view it from underneatch, make sure this is tightened as much as possible.

After doing these, check to see if the slide cycles better. I have the kwa usp compact, should be the same but bigger I imagine. But those tips are good for all GBBs, worked on my glock too. I can now get one full mag fired if I pace the shots a little. All green gas pistols will suffer if you fire them too fast. But they can be fired fast enough to be effective you just have to rely on aiming more than pulling the trigger.

Just tested mine there and it did alright. Also note that sometimes the slide will not cycle back far enough to engage the slide catch but will still be able to successfully load the next BB. Could just be that the USP doesn't cycle the best way, but 15-20 shots in this weather should be attainable and the full size USP should have a larger gas cannister, unless the slide is a lot heavier as well.

Bemused

Thanks for the detailed response and ideas.

Everything is cleaned and lubricated and the screw (which I did not know about) is tight. I guess I am used to TM pistols where this is not an issue because of the lighter slide. I can fire them as fast as I can pull the trigger even in pretty cold temperatures.

Would a weaker recoil spring do the trick?

CpcRc wrote: »

Have you lubricated the rails on the slide and lower frame?
Have you lubricated the internals with silicon oil for smoother action on the trigger?
Also when you lock the slide back, there should be a screw on the top slide when you view it from underneatch, make sure this is tightened as much as possible.

After doing these, check to see if the slide cycles better. I have the kwa usp compact, should be the same but bigger I imagine. But those tips are good for all GBBs, worked on my glock too. I can now get one full mag fired if I pace the shots a little. All green gas pistols will suffer if you fire them too fast. But they can be fired fast enough to be effective you just have to rely on aiming more than pulling the trigger.

Just tested mine there and it did alright. Also note that sometimes the slide will not cycle back far enough to engage the slide catch but will still be able to successfully load the next BB. Could just be that the USP doesn't cycle the best way, but 15-20 shots in this weather should be attainable and the full size USP should have a larger gas cannister, unless the slide is a lot heavier as well.