Colt AR serial number help.

[Acera]

I just got this rifle in a multifaceted horse trade and wanted to find a little more information about it.

I have checked in the Blue Book of Gun Values and I think it places the production date close to 1976, within 100 of the end of the SP1 run.

Checking this website, I think it puts it there also. Now this site shows the SP1 produced until 1978.
http://www.biggerhammer.net/ar15/ar15serial.html

My issue is that none of these use the serial number format I have, SP1 XXXXX, they all use SP XXXXX. Mine has the 1 on it, usually the published serial numbers are pretty accurate, and I would think leaving off the "1" would be an issue. Is it part of the serial number on my gun?? I would think so. Do I have a 5 or a 6 digit number. I would have guessed 6, but none of the literature I can find has a 6 digit number listed for the SP-1's. (Before you ask, yes there is a number under each of the black boxes.)

So what do I have here. Triangle hand-guards, slick side receiver, birdcage flash hider, no forward assist, no brass deflector, thin barrel, typical early featured early rifle.

 

[Shear_stress]

Nice rifle. The SP1 was made from 1963 to 1984. The Blue Book doesn't say production ended in 1976--they only attribute that date to the end of "early production" for some reason. Serial numbers on Biggerhammer.net end at 1978 because that was the last year Colt made them available publicly.

The "1" is part of the serial number, so your gun was probably made in the early 1980s. If you want to know an exact date, give Colt a call. Hope that helps.

Edited to add:

Triangle hand-guards, slick side receiver, birdcage flash hider, no forward assist, no brass deflector, thin barrel, typical early featured early rifle.

Those were features of all SP1s throughout production, with the exception of the flash hider. Early guns went through several variations of three-prong units. Sixties-era guns also could have chrome plated bolts/carriers, no forward assist cuts on the carrier, unplated bores/chambers as well as numerous other differences that retro AR geeks go crazy over.

 

[Acera]

Thanks Shear_stress,

That really cleared up the confusion. No chrome plated bolt or carrier though, and it has the cuts on the carrier. Still happy to have this thing, even though it is not as old as I once thought, LOL.

I appreciate the help.