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11/24/2017 4:44:23 PM
11/22/2017 10:05:29 PM
Posted: 8/19/2004 3:02:35 AM EST
I'm planning on purchasing a new upper and I had a few questions. I own a Colt Carbine, which is essentially a Gov't Model 6520. The front pivot pin lug uses a screw to hold the upper in place and the rear lug uses a pin. The upper I'm interested in purchasing is a Colt M16 M4 A3 16" and pictures can be seen here.

I'm assuming this upper will fit my lower, but I'm not 100% sure because of the small hole / big hole issue. I've read the description of each hole here, but I'm still not sure. If it doesn't fit, can I buy a new pin that will make it fit?
Link Posted: 8/19/2004 3:15:59 AM EST
I believe it's a large hole lower and a small hole upper, the fix is here:
www.bushmaster.com/shopping/lowers/nes-06.asp
Link Posted: 8/19/2004 5:01:30 AM EST
My AR15-A3 carbean came with the screw front pin, and it's a small hole lower. (I had it converted to push pin) If your front pivot pin is the same size as your rear, then you're good to go.

The large hole is very obviously larger than the rear push pin.
Link Posted: 8/19/2004 3:02:09 PM EST

Originally Posted By Gunslinger808:
I believe it's a large hole lower and a small hole upper, the fix is here:
www.bushmaster.com/shopping/lowers/nes-06.asp



Works very well, give it a try.
Link Posted: 8/19/2004 4:00:59 PM EST
[Last Edit: 8/19/2004 4:07:50 PM EST by shamayim]

Originally Posted By fq1234:

Originally Posted By Gunslinger808:
I believe it's a large hole lower and a small hole upper, the fix is here:
www.bushmaster.com/shopping/lowers/nes-06.asp



Works very well, give it a try.



The fix is NOT there! That's a PITA part. It rotates out of position every time you open the action; you have tov use a screwdriver to reposition it; and sooner or later you get careless and gouge the reciever; or if you're lucky, you just mess up the slot of the pin.

Instead, the fix is HERE www.cdnninvestments.com. Scroll to the AR parts section and look for part #TAR2. Thst adapter, once set, stays in place when you open the piece up; whether once or a hundred times.

You'll hate yourself if you buy the Bushie piece.
Link Posted: 8/19/2004 4:06:09 PM EST
Just because your current lower uses the screw type pin it does not mean that it a large hole lower! My Colt has that screw set up and it is still the mil-spec size front hole. You can even convert it to a regular push pin.
Link Posted: 8/19/2004 4:25:20 PM EST
[Last Edit: 8/19/2004 4:26:12 PM EST by fq1234]

Originally Posted By shamayim:

Originally Posted By fq1234:

Originally Posted By Gunslinger808:
I believe it's a large hole lower and a small hole upper, the fix is here:
www.bushmaster.com/shopping/lowers/nes-06.asp



Works very well, give it a try.



The fix is NOT there! That's a PITA part. It rotates out of position every time you open the action; you have tov use a screwdriver to reposition it; and sooner or later you get careless and gouge the reciever; or if you're lucky, you just mess up the slot of the pin.

Instead, the fix is HERE www.cdnninvestments.com. Scroll to the AR parts section and look for part #TAR2. Thst adapter, once set, stays in place when you open the piece up; whether once or a hundred times.

You'll hate yourself if you buy the Bushie piece.



Actually, I have the CDNN part that you are refering to. I has all of the problems that you refer to (really not to big of a deal though). The BM part that someone posted earlier looks like a good fix. It seems to fit into the receiver so the screw can't rotate like you mentioned. I think you must have been mistaken in your post. The CDNN does not stay in place as you say. I haven't tried the BM part but it must stay in postition better than the CDNN part. Trust me...the CDNN does not stay in postion...If it did I would be about 2 years younger right now...
Link Posted: 8/19/2004 4:29:13 PM EST

Originally Posted By rockytherotty:
Just because your current lower uses the screw type pin it does not mean that it a large hole lower! My Colt has that screw set up and it is still the mil-spec size front hole. You can even convert it to a regular push pin.



Is there a reason to switch? Have the screw front pin and never had an issue with it....
Link Posted: 8/19/2004 4:35:44 PM EST

Originally Posted By easy610:

Originally Posted By rockytherotty:
Just because your current lower uses the screw type pin it does not mean that it a large hole lower! My Colt has that screw set up and it is still the mil-spec size front hole. You can even convert it to a regular push pin.



Is there a reason to switch? Have the screw front pin and never had an issue with it....



Just for convienence. A lot of the small hole screw type lowers have the holes drilled for the take down detent. If the detent hole is there, it only costs a couple of dollars to convert over. The push pin system is much easier and quicker to use.
Link Posted: 8/19/2004 5:02:45 PM EST

Originally Posted By easy610:

Originally Posted By rockytherotty:
Just because your current lower uses the screw type pin it does not mean that it a large hole lower! My Colt has that screw set up and it is still the mil-spec size front hole. You can even convert it to a regular push pin.



Is there a reason to switch? Have the screw front pin and never had an issue with it....



Once you get used to the push pin up front, you'll wonder why you waited so long. I don't think you have the large hole upper personally.
Link Posted: 8/19/2004 5:07:27 PM EST

Originally Posted By markm:
I don't think you have the large hole upper personally.



One way to find out, MIC it! (micrometer measurement)
Link Posted: 8/20/2004 2:16:34 AM EST
I'm going to just buy the upper and see if it fits. If not, I'll try one of the pins you mentioned. Thanks CF
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