Help with Lower Pin > AR-15 / M-16 Retro Forum

Posted: 4/22/2015 9:51:39 AM EDT

I'm working on a retroish 9mm build and I'm trying to figure out what I can do for the front take down pin. I've order the NDS 601 lower for the slab side look that uses the NDS detent pin on rebate lug upper. However the upper i'll be using is an original Colt 9mm Al upper that takes the standard small size upper pin. I would prefer to have the Colt screw type pin like used on an SP1 but I do not know of anyone making that style for a small hole upper and lower.

By chance does anyone know where I could pick up a small pin 'SP1" style pin & screw? Or possible other options I have?

Posted: 4/22/2015 9:58:10 AM EDT

[#1]

So the Colt upper is large or small pivot hole? Large hole upper to standard lower is always the toughest to mate up.

Posted: 4/22/2015 10:18:00 AM EDT

[#2]

rebate the upper and the pin from NDS will work.

Posted: 4/22/2015 10:24:26 AM EDT

[#3]

Got 5 minutes and a drill press?

Posted: 4/22/2015 10:32:14 AM EDT

[#4]

I have a .250 sp1 pin

Posted: 4/22/2015 10:33:29 AM EDT

[#5]

The Colt 9mm upper takes the Sm pin.

Call it crazy but was really wanting to find a small pin size SP1 style screw....Dose anyone make them?

Posted: 4/22/2015 10:34:34 AM EDT

[#6]

Quote History

Quoted:
I have a .250 sp1 pin

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Where do you find one at? Is it for sale?

Posted: 4/22/2015 10:45:31 AM EDT

[#7]

I need to rebate an upper as well, can some tell me the drill size and the depth? I know if you go too deep the pin will have slop.

Posted: 4/22/2015 11:00:12 AM EDT

[#8]

It's .312" diameter and .080" deep.

And it has a square shoulder at the bottom of the hole so you should use a 5/16 end mill.

Posted: 4/22/2015 11:08:14 AM EDT

[#9]

Quote History

Quoted:
It's .312" diameter and .080" deep.

And it has a square shoulder at the bottom of the hole so you should use a 5/16 end mill.

View Quote

Thank you Mike!

Posted: 4/22/2015 11:50:00 AM EDT

[#10]

He wouldn't offer it up if he wasn't trying to sell it to you or help you out... Also it is the pivot pin, the rear pin is the takedown pin.

. Good Luck.

Posted: 4/22/2015 12:10:52 PM EDT

[#11]

Yep....Looks like we have an awesome deal worked out....Thanks to all for the help!

Posted: 4/22/2015 9:34:07 PM EDT

[#12]

http://www.knsprecisioninc.com/gun-parts-and-accessories/ar-15-parts/replacement-pivot-pin-250-dia.html

Posted: 4/22/2015 10:59:07 PM EDT

[#13]

oh, at least one exists, a one off Heatnbeat heap of awsomesauce.

the oem Colt's do not have a screwdriver slot on one side, instead a flat to but up against the fence.

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[ARCHIVED THREAD] - Help with Lower Pin