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Gunsmithing & How To Pro, Amateur & WECSOG and Tutorials, Guides & OLL Build Instructions |
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#1
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Upper and lower mating issue - rear pin hole out of alignment
Hi everyone. I just built my first lower (hooray!) to go with an upper I had forgotten about that was in the safe.
When I mate the two together, they go together great... except the rear pin socket in the upper is about 1/16" out of alignment. Here is a photo of the upper and lower just before mating. and after mating, with me holding the upper and lower together (to get the lugs to line up as much as possible) My question is this. What can I do to fix this to get them to mate correctly? At this point, the pin won't go through with hand force at all. The rifle does seem to function. I can pull the charging handle (while keeping the two halves together) and otherwise, the rifle seems to be functioning correctly, though until I can get it to the range I won't know for sure. However, without the pin in, I don't want to do a live fire function test. Any suggestions would be greatly appreciated. thanks Mel
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NRA Patron Les Baer TRS, Kimber Ultra Raptor II, S&W 910, Remington 870 Express, CMMG AR-15, S&W 460XVR, Nemesis Arms mini-windrunner (Vanquish), Stag Arms AR-15 Lower with Daniel Defense parts |
#4
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The upper is unmarked. So to be honest, I do not know. It was bought from a friend of a friend who was heading back out to be deployed.
The lower is a Stag Arms with Daniel Defense parts. jamesob, that was one of the first things I had checked. It definitely isn't in too far. The flared lip of the tube traps the buffer retainer spring and it also doesn't block the upper from coming down. To verify, however, I backed the buffer tube out and attempted to mate the two halves. Still no joy.
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NRA Patron Les Baer TRS, Kimber Ultra Raptor II, S&W 910, Remington 870 Express, CMMG AR-15, S&W 460XVR, Nemesis Arms mini-windrunner (Vanquish), Stag Arms AR-15 Lower with Daniel Defense parts Last edited by melodybliss; 10-01-2011 at 3:29 PM.. |
#5
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I had this done to a customer of mine awhile back...
http://www.calguns.net/calgunforum/s...d.php?t=456187 easy fix... so easy dont laugh now... just drill it thru than aluminum black it... the top and bottom fit but pin wouldn't so i got same diameter drill bit of receiver hole and slowly made my way thru... presto pin fit with no other problems... and honestly really doesn't matter what upper and lower you have that's not going to solve the problem at hand... Last edited by Milspec714; 10-01-2011 at 6:01 PM.. Reason: add link |
#11
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killmime1234, I took a look. It looks fine there. I think that's a photo artifact and isn't extra material.
I think I'll end up drilling the area out so that it opens it up by that last 1/16. I'll mark it first with a sharpie to make sure I'm removing only what I need to. Thanks everyone. I'll let people know how that goes once it's done.
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NRA Patron Les Baer TRS, Kimber Ultra Raptor II, S&W 910, Remington 870 Express, CMMG AR-15, S&W 460XVR, Nemesis Arms mini-windrunner (Vanquish), Stag Arms AR-15 Lower with Daniel Defense parts |
#12
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The front pin is in place, right? If it were me I would not drill through both the upper and lower at the same time. Mark the upper with a needle or other sharp pick while it is on the lower, separate and either file or dremel the marked portion on the upper. Otherwise you stand a good chance of enlarging the holes in the lower.
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#15
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WTH.Do you have a friend or something with another upper to compare and try theirs on yours.Sorry,just never seen it before.Have only dealt with Colt,Bushmaster,Dpms and recently S&W,BCM.Everything has been interchangeable just fine.Wish you were near me,I would bring some stuff to help you decide your next move.
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#16
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Quote:
Quote:
remove take down pin start with 7/32 bit with a drill at slow speed and just do a couple of passes to get rid of excess and move up to a 1/4 bit which will fit tight but not enlarge your holes..this is where you use the vise grip by hand trick, like i do go from both sides until you can thru all the way... re-install take down pin and test... use birchwoods casey aluma black to touch up visible aluminum hope it works out for you.. |
#17
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So before I start doing any drilling, we pulled the CMMG AR out of the safe and I took it apart.
It looks like it's a lower issue and not an upper. The CMMG lower takes the upper I thought that was out of alignment. The CMMG upper has the same problem on the Stag Arms lower. :/ I'm guessing I should contact Stag Arms for this. Thanks everyone for your help. Mel
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NRA Patron Les Baer TRS, Kimber Ultra Raptor II, S&W 910, Remington 870 Express, CMMG AR-15, S&W 460XVR, Nemesis Arms mini-windrunner (Vanquish), Stag Arms AR-15 Lower with Daniel Defense parts |
#19
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"Amen" to that, Purple K!
Thank you for the simple fix. I was reading all those suggestions to start altering the machine work and even some suggestions to "hand drill" on the lower and it was giving me a serious case of the stuttering WTFs (at least use precision basic garage implements like vices and drill presses, at low-speed if you wish). At least some people (including the OP) were sensible enough to recommend he defer to the manufacturer or a professional gunsmith but your one sentence comment was the greatest of them all. I was working with a PSA lower (built by me) and a PSA upper (purchased fully assembled) and completely stumped. Now keep in mind, please, this is the first AR15 that I've ever built. Heck, this is the first gun of any kind I've ever built. And my education on the matter is all from the esteemed YouTube University at the internationally renound campus of the WWW. I couldn't imagine I'd had the rotten luck of getting my first purchase to also the rare blem or part that snuck past the QC station. I didn't want to give up and now I'm glad I was patient enough to just keep reading. Sorry for bumping a post so old it might have been originally written on stone tablets but this really helped a noob like me and maybe it would help someone else too. |
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