What can you tell me about this Colt AR15 I'm buying?

[Boboclown]

Don't you need to screw out both sides? I never had to use any of the adapters, and I can't see it from the pics.

 

[Joe Link]

Don't you need to screw out both sides? I never had to use any of the adapters, and I can't see it from the pics.

That's what I figured, but the pin side only turns maybe 45 degrees before stopping. Looking at photos the sides are smooth and it doesn't appear that it threads into the upper or the lower, so I'm really not sure.

 

[jbett98]

To separate the upper and lower on an SP1 you need two screwdrivers to remove the front hinge pin. Use one screwdriver to hold or stabilize the screw on the right side of the receiver.
The screw head on the left side is a cap screw. While holding the one on the right with the first screwdriver, loosen the cap nut screw on the left with the second screwdriver. Once the cap is off, drift the pin out to the right. Be careful of the threads.

 

[Joe Link]

To separate the upper and lower on an SP1 you need two screwdrivers to remove the front hinge pin. Use one screwdriver to hold or stabilize the screw on the right side of the receiver.
The screw head on the left side is a cap screw. While holding the one on the right with the first screwdriver, loosen the cap nut screw on the left with the second screwdriver. Once the cap is off, drift the pin out to the right. Be careful of the threads.

Yeah that's what I thought. Even though the cap screw is off I still can't push the pin screw out. I didn't want to use a hammer to tap it out without knowing if that was the right move.

 

[jbett98]

Screw the cap screw on at least 4 or 5 threads and then gently tap the cap crew head with a plastic head hammer.
It should move the pin screw head back out a bit. A drop of Kroil would help if you have some, but any penetrating oil will do.

 

[Joe Link]

Screw the cap screw on at least 4 or 5 threads and then gently tap the cap crew head with a plastic head hammer.
It should move the pin screw head back out a bit. A drop of Kroil would help if you have some, but any penetrating oil will do.

Awesome I'll give that a shot. I have reason to believe it hasn't been removed in 20 years.

 

[parallax]

Can you tell us, by the serial number what year it was born?.

 

[Joe Link]

Good question! I won't know until I call Colt. Serial is GS009xxx.

 

[Kruel J]

Congrats on the Franken-Colt. I'd shoot the heck out of it!

 

[Boboclown]

Serial is GS009xxx.

It will probably be 80s or later. Don't know the date but it would be in the pre-ban area.

 

[jbett98]

My money is on "1985"
Maybe we should start a betting pool on the outcome.

 

[Kruel J]

At this point the only thing I would bet is that squeezing the bang switch will cause a reaction to facial muscles.

 

[Joe Link]

When did they start and stop making the non-fenced lowers?

 

[Boboclown]

My money is on "1985"

I bet it'll be later than that, maybe 88 or 89?

When did they start and stop making the non-fenced lowers?

1990 or 1991 I think.

 

[Unka-Boo]

Good question! I won't know until I call Colt. Serial is GS009xxx.

see here: Colt AR-15 Serial Number List

Colt 6550....all references I can find show it as a 20" rifle....so, my gut may be right...swapped upper, or parts gun built on Colt lower. Either way, you did good, shoot it without worrying about "collector value ".

 

[Joe Link]

see here: Colt AR-15 Serial Number List

Colt 6550....all references I can find show it as a 20" rifle....so, my gut may be right...swapped upper, or parts gun built on Colt lower. Either way, you did good, shoot it without worrying about "collector value ".

View attachment 349371

I've been researching this thing for days, and I think you're right! I called Colt and this one is a 1990. He said it's in the system as a Sporter Rifle 22LR 20" so it sounds like mine came with the .22LR kit as well. I think that makes it the 6550K?

Turns out the bigger mystery is the upper. As far as I can tell Colt didn't make an A2 upper with a 16" 1/9 twist barrel and the M4 cut. It may have come on an AR6525 but I can't find any photos or info to confirm whether that gun had the M4 cut. It does have extended feed ramps and the half-moon BCG (though the lower does not have the sear block).

 

[orygun]

I think this is a pretty cool gun I'd shoot the heck out of.
I don't know much about AR15 specifics and have really enjoyed reading along as this thread grows.

My only question is, why does the barrel look like it's 5 or 6" too long?

 

[Joe Link]

I think this is a pretty cool gun I'd shoot the heck out of.
I don't know much about AR15 specifics and have really enjoyed reading along as this thread grows.

My only question is, why does the barrel look like it's 5 or 6" too long?

It's been a blast researching exactly what it is that I bought, but it won't be taking the place of my 6920 anytime soon. What I'd really like to do is build two Colts out of this one, a 6550 with the lower and a 6525 with the upper (if that's what it turns out to be). Unfortunately I doubt I'll be able to afford a legit, proper 6550 upper, so I might end up selling the lower. I'm not a big fan of franken-guns.

 

[Boboclown]

As far as I can tell Colt didn't make an A2 upper with a 16" 1/9 twist barrel and the M4 cut.

Barrel may be newer. Only Colt AR with A2 upper that is a 16" barrel with 1/9 is the R6721, which didn't have the M4 cut.

this one is a 1990

Okay so I was wrong by 1 or 2 years. Not bad for not being alive then.

 

[Joe Link]

Barrel may be newer. Only Colt AR with A2 upper that is a 16" barrel with 1/9 is the R6721, which didn't have the M4 cut.

The odd thing is the receiver has the extended feed ramps. Did they do that for non-M4 barrels too?

Okay so I was wrong by 1 or 2 years. Not bad for not being alive then.

Nah man you know your stuff!