Found 2 old AR pre-ban uppers that won’t fit any of my lowers

[Ed L.]

A family member found two old uppers that have been warehoused for decades. They have no idea where the matching lowers are.

One is from a 1980 vintage Colt SP-1. It has triangular handguard. The other is from a late1980s vintage Colt AR-15a2 HBAR.

Neither will fit any of my current ARs and I suspect that any lower that will fit one of these uppers will not fit the other.

When I put the SP1 upper on a Colt 6920 lower, the rear takedown pin will not go in.

When I put the HBAR upper on a Colt 6920 upper, the rear pin will close but the front pin is incredibly loose to the point that there is an enormous amount of play between the upper and lower because the upper has a much bigger hole for the pivot pin. Take a look at this not very good cell phone photo below that shows the gap between the HBAR upper and the Colt 6920 lower when the pins are closed:



So I have two AR uppers that will not fit any of my AR lowers, and any lower that will fit one of these ARs will not likely fit the other.

Does anyone make a modern lower that will fit either of these or do I have to search for a pre-ban lower or maybe we should just sell these uppers?

thanks

[ezveedub]

The Colt SP1 upper will probably need the offset front pin adapter and the HBAR has the large hole front pin and needs an adapter as well.

[scottryan]

Can you take a picture of each upper?

They are both most likely large front hole uppers. They aren't worth anything and I would shitcan them on gunbroker.

[Ed L.]

Thanks, guys.

Definitely large hole uppers that will not fit current ARs.

Am having photo problems, will post later.

[Ed L.]

I am having major F problems with photobucket so this may take a while . . . Photobucket is inverting and turning around pictures that I am loading. Using photobucket will correct any low blood pressure issues.

[ezveedub]

You need the original Colt large hole slab side lower with the screw together front pivot pin/bolt for that upper. Was just working on one last weekend.

[SeriousStudent]

Ed, before you take them to GB, it might be worth asking our mutual friend Wayne. He might know somebody that could be interested.

Couldn't hurt, and might help. Good luck.

[ClassIIIGunsmith]

Old colt uppers have .315 diameter front pins which means you need a old sp1 lower to have a working rifle/ sell them for good money to somebody who needs an upper

[Ed L.]

I plan to buy an SP1 lower for the triangle handguard upper. I like it because that is what M-16s looked like when I was a kid and young adult. It's what they looked like in all of the movies and TV shows of the time. It is also like the gun I shot in ROTC.

[Ed L.]

Here is a photo of the HBAR upper on a 6940 lower. I used a DPMS Offset Pivot Pin Adapter Bushing .315" to .250" Diameter. Even though there is no massive wiggle in the front, however if you look at the rear where the arrow is, there is a noticeable gap between the Colt AR15A2 HBAR upper and the Colt 6940 lower. It is more apparent in person than I am able to depict with my photo.

I'm not one of those people who think the upper and lower need to be super tight, but if you were to look at the gap in person, you could imagine lubrication and other things squirting out when the gun is fired.