(I am new here, so I hope I am posting in the proper forum.)

I want to replace the pivot/take-down screw-type pin on my 1987-vintage Colt HBar AR15. I measured the diameter of the pin part (with the female threads) and it varies from .3166 to .3163 through its entire length, a variation of only 0.0003.

I have read that the replacement easy-removal type pins are 5/16 diameter (5/16 = .3125). The problem is that a pin of this diameter, .3125 would fit rather loosely. (I used a plain .3125 gage pin just to test the fit.)

Are the replacement pins really .312 and not .316 diameter, or do people just round the .316 to 5/16 and then call it .312?

Thanks for your inputs -

Alex

I don't know if this will help but try:

[url]www.biggerhammer.net[/url]

the site shows some pics and measurements of frt pins/holes.

That seems like an awful lot of trouble to go to. When I wanted to get rid of that godawful screw pin, I just went to a gun show and bought an aftermarket push pin and it works just fine. They only come in two sizes which are easy to tell apart. Trust me, just buy the bigger one and it will snick right in.

What's still a mystery to me is why Colt ever inflicted the screw pin on us in the first place. I've never heard an explanation that really made sense but I've got an idea of my own.

Thrush,
I want to hear your idea on that... I just bought a "front push pin" and it do not fit. Is there anything I can do or am I going to have to get rid of this Colt.. *screams and pulls out last of hair on head*

Which is bigger, the hole or the pin? Slabside lowers will always take the larger pin while those with the boss (most people call it the fence but I don't) will _usually_ take the .255" M16 size pin. My only guess is that you should try one of each.