Colt Upper on RRA Lower

[dwcraig]

I am trying to couple a Colt upper on a Rock River lower. I need to use a bushing on the pivot pin hole which I have purchased. The problem is that the bushing will drop right through the hole on the upper. It is an eccentric so I need to hold it in one position. Has any body ever used something like epoxy to keep the bushing from spinning around and changing the position of the eccentric? Any suggestions would be appreciated. Thanks.

[a308garand]

Use just enough of a small dab of JB weld to keep the bushing in place. Don't go overboard, just small enough amount to allow it to be removed (if needed) without causing damage to the upper or lower.

[dwcraig]

Thanks for the response. I assume the reason for the eccentric hole is to adjust the fit between the upper and lower. Any tips on the best way to determine what position to glue the bushing in? Thanks again.

[Pofoo]

Thanks for the response. I assume the reason for the eccentric hole is to adjust the fit between the upper and lower. Any tips on the best way to determine what position to glue the bushing in? Thanks again.

I believe you have a older Colt civilian model (Sporter?) that had a larger diameter pin than anything else ever made. I think it was some kind "trick" to beat gun control laws in the '90's. Didn't work, still banned.
So, with mismatched upper and lower, you have 2 different size holes. It is not designed for adjustment. With a Colt upper and lower, the large pin goes right in.
I think you can use the pin as a guide to glue the eccentric. I would epoxy it well and consider it a permanent install. I wouldn't want to risk it falling out.
Use some kind of temp adhesive (rubber cement?) and line it up with the pin installed and let dry, then mark the eccentric and frame and re-glue with epoxy.

[RandyD]

I have a Colt upper and have been looking for a bushing so I can do the same thing. Where did you get your bushing?

[biglou]

Are you talking about one of these: http://blackrifleworks.com/colt-ar15...pin-p-164.html

[dwcraig]

I got my bushing from Rock River Arms. Brownell's also sells it. I glued it in with slow dry JB Weld this morning. I assembled it and then took it apart several times until I had a nice fit. Waiting for glue to dry now.

[Roccobro]

Are you talking about one of these: http://blackrifleworks.com/colt-ar15...pin-p-164.html

Other way around. Big hole upper, small hole lower.

Justin