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1/18/2004 7:10:19 AM EDT
Has anyone ever tried to convert a Colt large front pin to the mil spec size?....I know it would need refinishing after.

What about drill a mil-spec upper out to accept the large front colt pin. I would much prefer the first option but does anyone know why this wouldn't work?

Thanks
1/18/2004 7:24:43 AM EDT
[#1]
According to my local smith it isn't very hard to change the lower pin size. Supposedly you fill the hole with something like JB weld and then redrill it to "milspec".

I had entertained the idea of doing it to both of my preban blue label Colts, but since they are slabsides there isn't a place for the detent pin.
1/18/2004 11:31:08 AM EDT
[#2]
Quoted:
Has anyone ever tried to convert a Colt large front pin to the mil spec size?
View Quote


John Norrell used to offer this service, but I don't believe he does it anymore.

What about drill a mil-spec upper out to accept the large front colt pin? I would much prefer the first option but does anyone know why this wouldn't work?
View Quote


Technically, the front lug on a small-hole upper doesn't have enough "meat" around the hole AFTER drilling to large-hole spec. It would be weaker than a factory large-hole upper and may break. You have to remember that the center of the small and large pivot holes is NOT in the same position. You could weld up the small hole and add extra weld around the outside of the lug. Then mill it off flat on all sides and redrill the large hole. Seems like an awful lot of work.

I'm in the same position as you and am just going to buy a large-hole flattop upper and be done with it.

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