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Another USP dry firing issue.

USP dry fire bucking

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#1 SHAYDEE

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Posted 19 January 2013 - 12:43 PM

I've done a search and read a few posts related to the issue that I am having and it has helped a lot, but it still hasn't completely fixed the problem I am having.  So I'm making this post to see if anyone can help me pin point the problem.  Maybe the problem is slightly different than the others..  

Previous Problem:
-Swollen bucking
-Dry firing from the start.
-BB's would feed and get backed up and roll out of the barrel.

I replaced the bucking with a new one from KWA.
I also washed off the surrounding parts on the inner barrel and bucking to make sure there is no trace of silicon spray.

I tested it out this afternoon.  My mags are not cold and its about 73 deg outside.
I load my bb's perfect with no gaps.

-Fired about 10-12 shots no problem.
-After that it would start skipping and dry fire every other shots for the next 6-8 times i pull the trigger.
-After that it just starts to dry firing till i'm out of gas and it leaves a good amount of bbs in the mag

This time the bb's don't get backed up and roll out.  It just doesn't come out.
I cock the slide back and there's a bb at the top of the mag waiting to get fed and no bb stuck at the hop up.  I checked part #135 as advised in a previous post and it seems intact.

I don't understand how it will fire perfect for half a mag, then skip, then dry fire completely.

It's not my mags because I fired off all of them with my USP Match and it works fine no skips or dry fire.

What else could it be?  

Thanks in advance for the help...

#2 gcw360

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Posted 19 January 2013 - 03:48 PM

View PostSHAYDEE, on 19 January 2013 - 12:43 PM, said:

I've done a search and read a few posts related to the issue that I am having and it has helped a lot, but it still hasn't completely fixed the problem I am having.  So I'm making this post to see if anyone can help me pin point the problem.  Maybe the problem is slightly different than the others..  

Previous Problem:
-Swollen bucking
-Dry firing from the start.
-BB's would feed and get backed up and roll out of the barrel.

I replaced the bucking with a new one from KWA.
I also washed off the surrounding parts on the inner barrel and bucking to make sure there is no trace of silicon spray.

I tested it out this afternoon.  My mags are not cold and its about 73 deg outside.
I load my bb's perfect with no gaps.

-Fired about 10-12 shots no problem.
-After that it would start skipping and dry fire every other shots for the next 6-8 times i pull the trigger.
-After that it just starts to dry firing till i'm out of gas and it leaves a good amount of bbs in the mag

This time the bb's don't get backed up and roll out.  It just doesn't come out.
I cock the slide back and there's a bb at the top of the mag waiting to get fed and no bb stuck at the hop up.  I checked part #135 as advised in a previous post and it seems intact.

I don't understand how it will fire perfect for half a mag, then skip, then dry fire completely.

It's not my mags because I fired off all of them with my USP Match and it works fine no skips or dry fire.

What else could it be?  

Thanks in advance for the help...
There should be a little protrusion at the bottom of the cylinder (part # 135).. This pushes the BB onto the feed ramp and into the inner barrel.  If that is damaged it could be the issue.  Compare the end of your USP cylinder with your Match cylinder to see if there is any difference.  Also, look at the feed ramp at the base of the hop-up/inner barrel.  This could be damaged or misaligned causing the issue.

One way to check these issues is to visually inspect the cylinder as it loads a BB by looking into the breech while manually, slowly, bringing the slide forward.

#3 Chuck S

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Posted 20 January 2013 - 08:49 AM

Admin loading drill.  Since there is no extractor this differs slightly from the cartridge version.

1.  Clear the pistol -- Lock the slide open and visually check that there is no BB in the chamber.
2.  Insert fully loaded (but not OVERloaded) magazine in the pistol.
3.  Cycle the slide if possible.  If not use the slide lock to let the slide slam home.
4.  Remove the magazine.  If the magazine is a double stack the top BB should have changed sides in the feed lips.
5.  Lock the slide open and visually confirm there's a BB in the chamber.

If this doesn't work there is probably a magazine or slide problem.  First suspect is always the magazine.  If more than one magazine has a problem the issue is in the gun.  Sometimes the magazine catch isn't holding the mag in the correct position; sometimes it's the loading nozzle (or similar named part).

-- Chuck

#4 Outlaw1995

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Posted 20 January 2013 - 09:08 AM

View PostChuck S, on 20 January 2013 - 08:49 AM, said:

4.  Remove the magazine.  If the magazine is a double stack the top BB should have changed sides in the feed lips.
One thing: on the gbb pistols, the bb comes to a point (feed lips), it becomes single stacked at the top, and you cannot tell if there is a round on the other side like the LM4.

#5 Chuck S

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Posted 20 January 2013 - 10:47 AM

Thanks!  You're gonna have to visually chamber check the pistol then.  (My USP is 9mm (and LEM).  ;)  )

-- Chuck

#6 SHAYDEE

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Posted 21 January 2013 - 09:21 AM

Thanks for the replies!

I checked and everything is intact and aligned.  I checked and everything looks to work fine.  The bb is feeding correctly.

I tested it again and i noticed that the slide doesn't blow back all the way.
It fires half the mag and then starts to skip or dry fire.
I'm thinking since it doesnt go all the way back it can't feed the bb when it goes forward beause the slide didn't go all the way back.
I thought maybe it's the output of the mags, but all 6 of them are weak and dirty?  

Also the same problem is now happening with my Match.

One other thing I can think of now is that both of my slides is not lubed up well..  (I ran out of lube I need to buy some)
Do you think since the slide is not as lubed it is causing friction causing the slide not to move back all the way?

I can't get to my airsoft store until later on this week, but I'd like to know if my semi lubed slide is the cause due to friction.

Edited by SHAYDEE, 21 January 2013 - 09:21 AM.


#7 gcw360

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Posted 21 January 2013 - 09:35 AM

View PostSHAYDEE, on 21 January 2013 - 09:21 AM, said:

Thanks for the replies!

I checked and everything is intact and aligned.  I checked and everything looks to work fine.  The bb is feeding correctly.

I tested it again and i noticed that the slide doesn't blow back all the way.
It fires half the mag and then starts to skip or dry fire.
I'm thinking since it doesnt go all the way back it can't feed the bb when it goes forward beause the slide didn't go all the way back.
I thought maybe it's the output of the mags, but all 6 of them are weak and dirty?  

Also the same problem is now happening with my Match.

One other thing I can think of now is that both of my slides is not lubed up well..  (I ran out of lube I need to buy some)
Do you think since the slide is not as lubed it is causing friction causing the slide not to move back all the way?

I can't get to my airsoft store until later on this week, but I'd like to know if my semi lubed slide is the cause due to friction.
Have you tried a new can of gas?

#8 SHAYDEE

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Posted 21 January 2013 - 09:46 AM

Yes, it was a brand new can of green gas from Tac City.

#9 gcw360

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Posted 21 January 2013 - 10:04 AM

View PostSHAYDEE, on 21 January 2013 - 09:46 AM, said:

Yes, it was a brand new can of green gas from Tac City.
Does the nozzle screw on the can by any chance?  Is it Power Green?

#10 SHAYDEE

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Posted 21 January 2013 - 11:01 AM

View Postgcw360, on 21 January 2013 - 10:04 AM, said:

Does the nozzle screw on the can by any chance?  Is it Power Green?

I'm at work right now so I can't check, but I know for sure it's not Power Green.
It's the slim taller can.  I think it might be from Air Splat, but they covered it with a white label.

The nozzle isn't screwed on.

#11 SHAYDEE

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Posted 21 January 2013 - 04:47 PM

my mistake...

the nozzle does have has threads at the base..  
it's airsplat.com brand "Green Gas" 33.81 fl oz.

#12 General Pickle

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Posted 26 February 2013 - 01:15 AM

My guess is hat there isn't enough pressure to get the slide all the way back. How hard is it kicking? Does it fire with a strong authority? Or is it kind of barely getting rounds off? How is your gas efficiency? Leaky mags? Personally I'd try propane, but that's at your own risk, there's a whole process you'll need to do in order to run propane effectively, and even then it just doesn't work well for some people.





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