KWA KP5 (aka Umarex USP.45) misfiring/seal problem

Tertion · August 5th, 2011, 19:51

Like many other peoples here, I have misfirings with my USP (all action cycle but BB not exiting the barrel... but droping from it when I shake the gun, meaning that it's still going trought the Up-Hop...)

I tried everything... lubing, complete reassembly, ect ect... was in lot of pains...

Then,

I noticed that the mag was a little bit loose in the grip (maybe around 1mm of so.. not so much). So I tried to shoot while pushin on the bottom of the mag and Bingo ! Worked flawlessly (well, as long as I maintained the pressure on the mag...)

Any tought on what that could cause that ? The mag release lever that got weared up ?

Styrak · August 5th, 2011, 21:30

Are you making sure the mag is seated properly with a good smack?
If so, it would seem like the mag isn't sitting up far enough. Is the mag catch worn down? Is this a new gun?

Thenooblord · August 5th, 2011, 22:00

the BB could be jamming in a swollen hopup rubber, then the gun cycles and forces another BB into the chamber, forcing the first one out, replace the hopup rubber

Styrak · August 5th, 2011, 22:11

Quote:

Originally Posted by Thenooblord

the BB could be jamming in a swollen hopup rubber, then the gun cycles and forces another BB into the chamber, forcing the first one out, replace the hopup rubber

That wouldn't explain the magazine issue/solution.

Thenooblord · August 5th, 2011, 22:25

Quote:

Originally Posted by Styrak

That wouldn't explain the magazine issue/solution.

oops, i missed that part...

Strelok · August 5th, 2011, 23:42

Curious if the sear or lip that catches the magazine is worn down or not... Or hell, if you can take a picture of the top of the mag, curious if things are raised/sunken too much.

Danke · August 6th, 2011, 00:27

I find on my USP I have to download the magazine, and also when loading to lock the slide open, insert the mag and then slingshot the slide.

That way I'm sure the mag is seated.

Ballcancer · August 6th, 2011, 00:30

Yea this was happening with mine too ... Except it def. Wasn't a swollen rubber... I was just firing dry propane through and it would do this 6 bb's would jam up and the spit out ... Of course it would do this after three magazines consecutively

Tertion · August 6th, 2011, 12:11

This is not a brand new gun, but it's not old either (I fired what, 12-15 mags trought it ?).

During a game, a was able to try it with another mag (that was working for its user) and had the same issue. So the problem is not the magazine... It really seem that something is preventing it from sitting up far enough, as you said Styrak. (I can clearly see it when I push/release and play with the mag inserted but with the slide removed.

I can't tell if the mag catch is worn up, as I don't know is initial apperence/condition but... since it's the only thing in the gun that catch/grip the mag.... it has to be the faulty spot, right ?

EDIT : well,.... 3 mags later the trick of pushing on the bottom of the mag is not working anymore... and if I drop an BB from the front end of the barrel, musket-style, and shoot it work... should be the hop-up rubber then (at least now the confusion is over...)

I heard that KSC and KWA are cross-compatible on parts, is that right ? If so, that part : http://www.airsoftparts.ca/store2/in...roducts_id=356 (KSC Hop-up Rubber - USP/MK23) should work... right ?

AngelusNex · August 6th, 2011, 13:06

KSC and KWA are compatible yes.

I warn you, when you switch the rubbers, be careful not to lose the ball bearing. It'll fall and be lost to you forever if your not careful.

Tertion · August 6th, 2011, 13:09

Well thanks for you help everyones... I gonna try a new rubber and post updates on the case, for the others to know...

Tertion · July 29th, 2012, 00:16

Quote:

Originally Posted by Tertion

Well thanks for you help everyones... I gonna try a new rubber and post updates on the case, for the others to know...

I said it so don't flame accusing me of necro-posting ...

Buyed a KSC hop-up rubber from airsoftparts.ca.. did not even fit in the gun (but it could be a mistake about the version of the gas system... like NS2 vs System 7, I don't know).

Buyed another one directly from KWA USA (should have done that first :banghead: ) and it fixed the problem after some lubing.... great.

But after a game and a truckload of sand (cleaned afterward, duh) it started the same behavior again...

... I'm lost guys ...

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August 5th, 2011, 19:51	#1
Tertion Trader rating Join Date: Jun 2006 Location: Laval (Québec)	KWA KP5 (aka Umarex USP.45) misfiring/seal problem Like many other peoples here, I have misfirings with my USP (all action cycle but BB not exiting the barrel... but droping from it when I shake the gun, meaning that it's still going trought the Up-Hop...) I tried everything... lubing, complete reassembly, ect ect... was in lot of pains... Then, I noticed that the mag was a little bit loose in the grip (maybe around 1mm of so.. not so much). So I tried to shoot while pushin on the bottom of the mag and Bingo ! Worked flawlessly (well, as long as I maintained the pressure on the mag...) Any tought on what that could cause that ? The mag release lever that got weared up ?

August 5th, 2011, 21:30	#2
Styrak Trader rating Join Date: Jan 2007 Location: Saskatoon, SK	Are you making sure the mag is seated properly with a good smack? If so, it would seem like the mag isn't sitting up far enough. Is the mag catch worn down? Is this a new gun? __________________ Airsoft Sales and Repair/Upgrade Services

August 6th, 2011, 00:27	#7
Danke Prancercise Guru Trader rating Join Date: Oct 2007 Location: Danger Zone	I find on my USP I have to download the magazine, and also when loading to lock the slide open, insert the mag and then slingshot the slide. That way I'm sure the mag is seated. __________________ Airsoft, where nothing is hurt but feelings.

August 5th, 2011, 23:42	#6
Strelok Trader rating Join Date: Jun 2006 Location: Brandon Manitoba	Curious if the sear or lip that catches the magazine is worn down or not... Or hell, if you can take a picture of the top of the mag, curious if things are raised/sunken too much.

August 6th, 2011, 00:30	#8
Ballcancer Trader rating Join Date: Oct 2009 Location: Gravenhurst, ON	Yea this was happening with mine too ... Except it def. Wasn't a swollen rubber... I was just firing dry propane through and it would do this 6 bb's would jam up and the spit out ... Of course it would do this after three magazines consecutively __________________

August 6th, 2011, 12:11	#9
Tertion Trader rating Join Date: Jun 2006 Location: Laval (Québec)	This is not a brand new gun, but it's not old either (I fired what, 12-15 mags trought it ?). During a game, a was able to try it with another mag (that was working for its user) and had the same issue. So the problem is not the magazine... It really seem that something is preventing it from sitting up far enough, as you said Styrak. (I can clearly see it when I push/release and play with the mag inserted but with the slide removed. I can't tell if the mag catch is worn up, as I don't know is initial apperence/condition but... since it's the only thing in the gun that catch/grip the mag.... it has to be the faulty spot, right ? EDIT : well,.... 3 mags later the trick of pushing on the bottom of the mag is not working anymore... and if I drop an BB from the front end of the barrel, musket-style, and shoot it work... should be the hop-up rubber then (at least now the confusion is over...) I heard that KSC and KWA are cross-compatible on parts, is that right ? If so, that part : http://www.airsoftparts.ca/store2/in...roducts_id=356 (KSC Hop-up Rubber - USP/MK23) should work... right ? Last edited by Tertion; August 6th, 2011 at 12:56..

August 6th, 2011, 13:06	#10
AngelusNex formerly Sepulcrum Trader rating Join Date: May 2007 Location: Kingston,ON, aka Funkasia	KSC and KWA are compatible yes. I warn you, when you switch the rubbers, be careful not to lose the ball bearing. It'll fall and be lost to you forever if your not careful.

August 6th, 2011, 13:09	#11
Tertion Trader rating Join Date: Jun 2006 Location: Laval (Québec)	Well thanks for you help everyones... I gonna try a new rubber and post updates on the case, for the others to know...

KWA KP5 (aka Umarex USP.45) misfiring/seal problem

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