Tuning Gen1 impact top plate/guiding plate flexing when air tank is installed.

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biohazardman

biohazardman

Member
Jul 3, 2019
5,451
299
Herriman, UT United States
Like the title says the Guiding plate on the top of the gun is flexing when I install the bottle on the gun and it is pressurized. It flexes/bends so bad that it is impossible to remove the barrel and one of my magazines that fit tight before will not fit at all now. I have had this gun apart at least a dozen times and have never had a problem like this.

It all started when I found that the rear block had a bad barrel indexing pin. So FX to the rescue and they warrantied it. So all I did was put the new block on and now I can’t get it to stop flexing when I put air to it. I have taken it apart four times already put it back together three, it always flexes when pressure is applied, and I can’t figure it out.

Anyone run into this problem before?

In pieces again




 
I figured that out, after a bit of trial and error, the first time I put it together and had no troubles after that but now I am baffled as nothing I do seems to help much. Put it together for the fourth time and it is a little better but still enough flex so I can't get the barrel off without pulling the bottle and purging the plenum and reg. Looks like I will need to tear it apart again.
 
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For me once I align the top guide plate in place I slide in the barrel and adjust the polish plenum making sure I get the most clearance (visual gap between barrel/plenum) before I tighten that 4mm screw that holds onto the plenum. If I do it that way once I pressurize the gun I’m still able to pull the barrel out/ put back on. It’s not buttery smooth but will come off when I pull on it. 
 
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You can put the top rail screws in more or less bottomed out with barrel in and only snug them down after the gun is aired up. Remember the plenum is a sealed unit it won't go flying off like a rocket. I can't say i advise this, but I've done it with no issues.

Or make sure the barrel slides in and out nicely then snug them down with barrel installed and air it up. But that's probably what you've been trying. I had this issue when I first installed it.
 
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I had my MK2 apart probably dozen times and sometimes I could feel missalignement when pulling the barrel. And I figure it out...

When putting it together from loose parts on the table I only put all the screws in place and finger tight all of them with a tip of the fingers only on top and below and around. Then with one hand grab around (the top plate and action block or plenum) and hold it tight and start applying just a slighly bigger tourque two fingers only on allenkey. Then again a next round bigger torque and now I can put it on table and re-torque 3 Nm.

Never fully torque screws on one side and proceede to next side and a next side. Torque them in steps all around at once then all around again and again.

Try to keep parts alignement neutral
 
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Got it! ;^) With the gun fully assembled, for the fourth time, I put the bottle on and pressurized the system then removed it and purged the system three more, make that four more, times with the bolt behind the grip that holds the front of the plenum removed. Then after the last time adding pressure I installed the bolt and tightened it down. The barrel came right out when I tried to remove it. I guess things were binding somewhere and finally came loose and went into alignment.

The one magazine I bought on the classifieds that fit really tight no longer fits at all though. ;^( Maybe it will fit my M3.

Thanks guys you kept me after it for as long as it took.
 
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Yeh, I watched that video this one and a couple of others and did it very similarly, every time I took it apart and put it back together, but it still was not a happy gun. All is well now though with a little repetitive filling and purging to get things to alignment correctly. I have had this thing apart a dozen times and never had such a difficult time with it.

https://www.youtube.com/watch?v=D0GenXGS_98


 
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After dumping the pressure in the gun I removed the magazine then loosened all 16 of the screws on the rear butt, including the ones on the sideplates and magazine release plate. Then pried lightly between the rear block and butt plates. This gave the magazine a bit more room and as I held it in place, I then tightened all of the screws back down. Both mags fit again. Thumbs up.
 
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The video shows wrong sequence of torquing, sorry ER. How do you torque the wheel lug-nuts (or the head gasket screws) on your car? In "X" opposite side and cycling two-tree times over and again until final torque. When I see that powertool I am loosing my hair (I like it btw especially when you have lot of screws but only to rough in).

If you really want to have the assy stress free and perfectly aligned = the barrel sliding in-and-out without any friction, you

1.- loose finger tight the top/side 8 screws (how many really doesn't matter) and the bottom/side 8 screws all around a gun;

2.- with an allenkey loose finger tight the top/side 8 screws and the bottom/side 8 screws all around a gun;

3.- with an allenkey apply medium torque to the top/side 8 screws and the bottom/side 8 screws all around a gun;

4.- and finally go over all the screws with a torque wrench.

I have tree bigger/heavier torque wrenches for my cars, one medium just for anything, one smaller precision for bike CF frames, one digital screw drivers size and one mechanical screw drivers size in example for airguns or small mechanical gizmo's. Uhm, you can call me fanatic ;)


 
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I had the same issue to where I found that the top plate was actually bent. I purchased this Gen1 gun and a new power plenum came with it in a box ready to install, I think it was one of the 1st Power plenums to come out. Same troubles, barrel comes out hard and doesn't line up well to install it either when pressurized, worked fine with no air in it. I found that the front cap of the power plenum that screws into the main body was a loose enough fit that it was actually flexing enough to twist the frame of the gun when pressurized. As I did not purchase the power plenum from FX I looked at what may remedy it and what I did was to wrap the threads of the front cap with teflon tape until I had a tight fit when screwing it together - not ideal but it worked. This loose fitting end cap twisted the gun enough that it bent the top rail right above the pistol grip, bent enough that I had to straighten it.
 
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