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9/22/2017 12:11:25 AM
Posted: 10/7/2005 6:40:55 AM EDT
I assembled a Polish underfolder kit on a Ewbank receiver and the barrel is canted to the left by a few degrees. How can I tell if this is due to a crooked receiver or whether I riveted the thing together wrong? Here's the facts on this build:

1) The front trunnion is square between the front lips on the receiver; there's no obvious gap on one side but not the other.
2) The underfolder arms line up straight and parallel with the receiver when folded or when opened -- so I know the back of the receiver is pretty much square.
3) I don't think the barrel is bent.

Anyone had this happen to them? My previous two rivet builds have turned out great -- so I at least am not a complete noob at building. What's the best way to weld up holes in the receiver if I end up having to pull the barrel/trunnion and start over?

Link Posted: 10/7/2005 7:26:57 AM EDT
whats the chances that the barrel could have been pressed in crooked? I've never pressed one on before but I've wondered how much of a problem that could be.

Your best solution for welding up holes would be to mig or tig weld the hole using a copper backing plate. Pennies can be used for the backing but use pre 1982 dated pennies. Also avoid the 1943 penny as the majority of it's copper content was replaced with zinc coated steel due to the critical use of copper for the war effort.

Link Posted: 10/7/2005 8:42:36 AM EDT
[Last Edit: 10/7/2005 2:08:21 PM EDT by ozzy_the_nuke]
I had exactly the same problem. Your gas piston probably doesnt line up well with your gas port either.

Mine was due to stacking of tolerances. There are normally variances in receivers, especially heat treated receivers. These variances normally cancel out to a large degree. In my case, they added instead of cancelling. Just bad luck.

I ended up twisting the receiver back into shape and it came out OK. I sent a email to the guys here at work showing pictures what I did. I will send you an email through the board. If you reply back, I will forward the email I mentioned.
Link Posted: 10/7/2005 5:20:16 PM EDT
Thanks for the tip Ozzy! My underfolder = not crooked anymore.

Link Posted: 10/7/2005 7:02:13 PM EDT
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