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Posted: 8/24/2004 4:42:54 PM EDT
Hey Guys,

Does anyone know of a repair facility that would fill the large front take down pin holes in my Colt pre ban receiver and redrill the hole to the standard front pin size? The lower receiver has the raised fence, so I was also hoping to have the hole drilled for the detent to retain the front push pin. If anyone knows of someone that would do that, please post it here. This big pin is making me crazy. I am so tired of the goofy off-set adapter pins and two screw drivers to change uppers. Any information would be greatly appreciated. Thank you.

Link Posted: 8/24/2004 5:05:12 PM EDT

I've never heard of anyone doing this, but you never know. It would seem to be possible, at some cost, but most people just trade lowers rather than try it. Good luck, though.

Link Posted: 8/24/2004 6:04:52 PM EDT
John Norrel used to do this... not do it anymore.

Mike Klos at American-Manufacture has started doing it, but he is currently not accepting any new work, as he is busy, his mother has been ill for most of the yr with serious medical.

Hold onto what you got for the time being.
Link Posted: 8/24/2004 6:06:59 PM EDT

There are brass bushings/plugs that are available to plug the existing hole, if the new hole is on the same center, you can possibly find a stadard bushing that will do this all in one step for you. I do now know the difference in size between the hole you currently have and what you want, or if they are even concentric, but an aluminum plug may not be the best bet.

I cannot for the life of me think of what these were called when I worked with them some years ago, but essentially they are slightly oversized, knurled "plugs" that are pressed into aluminum. They can either be a sleeve, or you can get them solid if you need to locate a hole off center of the plug itself. Sorry I can't be of more help.
Link Posted: 8/24/2004 6:24:55 PM EDT

Originally Posted By snobordr:
if the new hole is on the same center...

They're not.
Link Posted: 8/29/2004 4:32:47 PM EDT
[Last Edit: 8/29/2004 4:34:38 PM EDT by canon3825]
Hey Guys, thanks for the posts. I have adapter pins with offset bushings etc. Most all of my collection is Colt. I live close to Mass. I have buddies down there. Once the ban goes away I still need a preban lower to shoot my preban uppers in Mass. I have an ArmaLite match trigger that I paid $185 for. I am tired of adapter pins and such in my SP1. I just want to push the pin and not have to deal with screwdrivers or bushings, or whatever. I would be hard pressed to find a Colt pre ban lower with a Mil Spec front pushpin and fire control pins with no sear block.

I have sent two SP1 lowers to Colt. They say that they could redo a lower for me but the lower has to be rollmarked "Colt Manufacturing". I have a lead on a pre ban lower that might be able to use. Who knows. Yes it would be easier just to buy a pre ban Bushmaster and have it colored gray to match my Colt uppers. It is worth the extra money to me to have a Colt. Thanks again for all your imput.

Link Posted: 8/29/2004 9:24:44 PM EDT
You could always use one of the bushings to adapt to a smaller hole size. If you wanted something more permanent for this, you could tap a small hold and put a small allen wrench set screw in.
Link Posted: 8/30/2004 4:51:13 PM EDT
Link Posted: 8/30/2004 5:08:15 PM EDT
[Last Edit: 8/30/2004 5:10:05 PM EDT by yellowjacket]
Hey canon3825,

Rock River Arms sells an Offset Pin which adapts a large hole lower to a small hole upper. I've never used one, but I think it screws together. It's listed in their latest catalog (available on the web) on page 25 as part number AR0192 for $4. It may not be what you want, but $4 has got to be better than welding up a Colt lower. JMO.

Ooops! Just re-read your post. Never mind my suggestion.


PS I did much better in math than in reading!
Link Posted: 9/2/2004 3:25:15 AM EDT
Link Posted: 9/2/2004 4:39:27 AM EDT
[Last Edit: 9/2/2004 5:43:01 AM EDT by Parrandero]
There is a push pin available for large hole Colts. Not sure, but think I got mine from Midway.

DPMS AR-15 Quick Takedown Pin .312" Diameter
Part # 400313


I have one of these pins and don't need it. If you would like to give it a try send me an email or Im and I will send it to you.

Link Posted: 9/2/2004 5:11:24 AM EDT
I have the same problem with my M16! Has anyone here ever drilled a small hole upper out to make it large enough to use the large push pin? Just curious about experiences. Thanks
Link Posted: 9/2/2004 6:51:36 AM EDT
I have jb-welded an aluminum rod into the large holes, cut flush, and then drilled the new holes. Sort of like a "made in place" bushing. It works great.
Link Posted: 9/3/2004 6:07:52 AM EDT
This guy says the holes between the upper and lower are not concentric. How would you locate the holes, using your plug and drill method??
Link Posted: 9/4/2004 8:56:10 AM EDT
[Last Edit: 9/4/2004 8:57:43 AM EDT by olephart]
Assemble upper to lower using rear pin. Put scraps of paper between upper and lower on the barrel end for clearance and uniform appearance. Lightly clamp the front end in position. Use a .250/251 centering punch through the push pin hole in the lower to locate the hole in the upper. Disassemble and drill.

If you don't drill the hole "square" the pin will force the upper/barrell out of line with the lower. Depends on the axis of the hole what will happen. Could make the rear of the upper hit on the lower when you try to close it or it could cause the sights to tilt relative to the lower (or both).

I don't think it's a job for a hand held drill.
Link Posted: 9/8/2004 5:05:44 PM EDT
Big question is, why would you do it? It would be a hell of a lot cheaper to use the modified pin assemblies that are available for cheap. That, and you don't screw up your lower.

Of course when my buddy and I get our shop up and running, we'll be more than happy to charge you a standard shop rate.
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