Help identify a colt please

[JacobWalker1996]

For starters I got the entire gun for 500 bucks ( I know, you hate me lol). I know its a pre ban bushmaster lower. The issue is the upper. It has a ton of colt markings but I can't figure out specifically which model it was.

Here's what I know:
- Slick side, no FA
- Heavy barrel
-The A2 flash hider is not original
- 20in barrel
- Ribbed handguards
- Colt marked bolt
- Colt marked barrel
- QC marks on ejection side of upper idk manufacture.
- Weird mark on front sight post

I would really like to be able to atleast know which model this upper is. I greatly appreciate any help in advance

 

[Rebel_Rider1969]

Twist is wrong for an a1. Should be 1:12. I may be wrong. Check the forward pin would be a small pin. Again could be wrong. Love the style though. In for the upper if you decide to sell it. Oops, no bayo lug, I'm out.

 

[JacobWalker1996]

Twist is wrong for an a1. Should be 1:12. I may be wrong. Check the forward pin would be a small pin. Again could be wrong. Love the style though. In for the upper if you decide to sell it. Oops, no bayo lug, I'm out.

It has the small forward pin. Needed a weird part to use the lower with large hole

 

[Rebel_Rider1969]

It has the small forward pin. Needed a weird part to use the lower with large hole

Yep a bushing. Well on the brightside there's a good chance the upper is Colt. It's the SP1 style. Ymmv.

 

[Rebel_Rider1969]

@TackleberryMCS

 

[JacobWalker1996]

Yep a bushing. Well on the brightside there's a good chance the upper is Colt. It's the SP1 style. Ymmv.

Ymmv?

 

[M60Gunner]

@pete repete @TackleberryMCS

Is JJ still around? I’m sure some of the more knowledgeable members will be along directly.

I lucked out and got a few Colts from some members here, latest was one just like this a few months ago

 

[TackleberryMCS]

My first inclination was that the upper assembly was from an early Colt AR-15A2, but I now question that as the upper receiver does not have the forge codes like there would have been if it was from a SP1 Sporter. The pivot pin is a mystery to me. I have never seen on like that. My first question is, are the pivot pin holes on the upper and the lower the same (.250")? If they are the same, then the upper receiver is likely from a Model 604 (M16) or an early Model 603 (XM16E1) as these did not have forge codes, only the proof mark by the port door. The barrel (non-HBAR) is definitely from a Colt A2. The Bushmaster lower was made by LAR for Bushmaster during the late 1990s to early 2000s. Not sure is the A2 handguards, stock, and grip are original Colt or Bushmaster or made by someone else.

 

[JacobWalker1996]

My first inclination was that the upper assembly was from an early Colt AR-15A2, but I now question that as the upper receiver does not have the forge codes like there would have been if it was from a SP1 Sporter. The pivot pin is a mystery to me. I have never seen on like that. My first question is, are the pivot pin holes on the upper and the lower the same (.250")? If they are the same, then the upper receiver is likely from a Model 604 (M16) or an early Model 603 (XM16E1) as these did not have forge codes, only the proof mark by the port door. The barrel (non-HBAR) is definitely from a Colt A2. The Bushmaster lower was made by LAR for Bushmaster during the late 1990s to early 2000s. Not sure is the A2 handguards, stock, and grip are original Colt or Bushmaster or made by someone else.

The pivot pins are different sizes. The front requires a bushing to be used on "modern" lowers

 

[JacobWalker1996]

My first inclination was that the upper assembly was from an early Colt AR-15A2, but I now question that as the upper receiver does not have the forge codes like there would have been if it was from a SP1 Sporter. The pivot pin is a mystery to me. I have never seen on like that. My first question is, are the pivot pin holes on the upper and the lower the same (.250")? If they are the same, then the upper receiver is likely from a Model 604 (M16) or an early Model 603 (XM16E1) as these did not have forge codes, only the proof mark by the port door. The barrel (non-HBAR) is definitely from a Colt A2. The Bushmaster lower was made by LAR for Bushmaster during the late 1990s to early 2000s. Not sure is the A2 handguards, stock, and grip are original Colt or Bushmaster or made by someone else.

I was mistaken, the rear is the smaller of the two

 

[JacobWalker1996]

I was mistaken, the rear is the smaller of the two

Some additional photos of the bolt

 

[TackleberryMCS]

I was mistaken, the rear is the smaller of the two

That would be an early Colt SP1 upper receiver - .250" takedown pin hole and .314" pivot pin hole. Dates back to the mid to late 1960s.

 

[TackleberryMCS]

Some additional photos of the bolt

Colt SP1 bolt carrier group.

 

[JacobWalker1996]

Colt SP1 bolt carrier group.

You are some sort of colt prodigy. Than you a ton man. I've been digging through old forums for weeks trying to get straight information lol. Is this a keep or sell item in your opinion. I flip a lot of guns but this seems like a nice one to hold onto

 

[TackleberryMCS]

You are some sort of colt prodigy. Than you a ton man. I've been digging through old forums for weeks trying to get straight information lol. Is this a keep or sell item in your opinion. I flip a lot of guns but this seems like a nice one to hold onto

It has some good parts (older SP1 upper receiver, charging handle, and SP1 bolt carrier group) that could be valuable to someone trying to refurbish an older SP1. That said, some early AR-15A2 Sporter II rifles had SP1 upper receivers, but most were mounted on SP1 type slabside lower receivers. Those lowers were soon replaced with A2 type lowers with the larger .314" pivot pin hole. The SP1 type upper receiver was soon replaced by an M16A1E1 type lower (forward assist and Brunton bump/brass deflector) which also had a .314" pivot pin hole. These were eventually replaced with an A2 type upper receiver. As it sits, it is a good rendition of a AR-15A2 Sporter II but done using an early ban-era LAR/BFI lower receiver. If it is not your cup of tea, you could always sell it and market it as an AR-15A2 "type" clone and emphasize the Colt parts that are on it as well as the early LAR/BFI lower receiver. With what you paid for it, it is quite possible to make a good profit on it with the right buyer. In the upper assembly alone, you have $500 worth of parts.