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4/4/2004 1:18:23 PM EDT
I'm new to this site. Has anyone used a Colt big pin upper on a Colt small pin lower? I know that there is an adaptor for this but I was wondering how it holds up and if there are any problems with this combo on a hard use law enforcement duty gun. Thanks.
4/4/2004 8:57:26 PM EDT
[#1]
Many people have or do use a Colt large hole pivot pin upper on a standard pin lower.  The problem with the adaptor is usually the adaptor screw working loose when the upper is pivoted open though I think this may apply more to small hole upper and large hole lower.  Some people have used adhesive to bond the adaptor insert permanently to the uppers large hole which helps prevent the loss of that piece and removal and insertion of the adaptor screw a little easier.  Others have had the upper converted to small hole by welding it up and reboring.

If you aren't the one opening the rifle up for cleaning or inspection, I wouldn't worry about it - just check that the screw hasn't worked itself out when you function check before use.

If I remember correctly, I may have read about the adaptor screw shearing in two due to poor receiver alignment, but that was a limited case.  I know I don't have problems but others may chime in otherwise as I don't put mine through hard use.
4/5/2004 7:17:49 PM EDT
[#2]
Any suggestions on who might be able to weld it up and recut to small pin profile?
4/6/2004 12:29:18 AM EDT
[#3]
Just saw someone post on this on another board and said he was sending his to Mike Klos at [url=http://www.american-manufacture.com]American Manufacturing[/url].  Sounds good, Mike has a great reputation.
4/6/2004 4:24:10 PM EDT
[#4]
Why not just replace the upper receiver?  Very easy, and would probably cost less than trying to have your existing upper modified.

-Troy
4/6/2004 9:21:48 PM EDT
[#5]
What type of Colt upper do you have and is it black or dark grey?
4/7/2004 4:56:23 PM EDT
[#6]
My upper is an early "Green Label" big pin upper. 20" gvt profile pre ban with flash hider, bayonet lug, and A1 sights. Dark Gray in color.
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