The three-prong was eliminated from new production of military firearms in 1966, but would remain in inventory until the A1s were replaced with A2s, twenty years and more later.Īnother early feature is the “Edgewater” buffer, so called because it was packed with edgewater washers.

Early parts include a front sight base that has been ground smooth front and rear, and a second-type three-prong flash suppressor. mil side of production, any leftover parts of the old, obsolete variety were diverted to civilian SP1 production. SP1s of that period still retained most early-production AR-15 features, because as rolling changes replaced parts on the. It also had a memorable serial number that tracked it to 1968. For one thing, as pictures showed, it was in very, very good condition, and if we know one thing about collectors, “Condition, condition, condition” is as much their mantra as “Location, etc.” is to realtors. There are reasons it might have gone that high. The fourth digit has been used many times as a way to different later models from earlier ones.A most surprising sale at GunBroker in which hot bidding led to a relatively ordinary Colt AR-15 Sporter (Serial SP1 11001) selling for a mighty high four large. As you can see, the exact meaning of the fourth digit depends largely on the preceding digits. Finally, the fourth digit is the finish or stock of your weapon: “1” is nickel or full blue finish, “2” is nickel or blue casehardened finish, “3” is nickel finish, “4” is Royal Blue casehardened finish and “6” is nickel finish.In the third digit is the caliber of the gun: “3” is 3 or 4 inches, “4” is 4.75 or 5 inches, “5” is 5.5 inches, “7” is 7.5 inches and “1” is 12 inches.The second digit of the model code is the weapon caliber: “4” is.“7” and “8” are employed occasionally to specify special variants. ”2” uses a frame from Colt Custom Shop while “3” utilizes a non-standard frame.

For the first digit, “1” means your Colt is the first model with a basic frame while “2”, “3”, “4” etc are the later versions.

1968 colt sp1 serial numbers