I just bought a 1980 made Colt AR 15 SP1 carbine. I had bought an SP1 rifle last year, so I’m thrilled to have a carbine to go with it. Those are quite rare here in Switzerland. Paid $ 1600 for it.

And it has a few strange features, if anyone has infos pls chime in.




Chromed BCG



Funny looking front pin






Colt mag with a circled (1)



Vinyl acetate covered stock



The nut is staked in two places, with a dab of black paint





Paint near the bolt release lever



Full auto hammer



Sear pin and full auto selector



The pin is quite lose and falls off



M16 BCG




So what’s the story, did Colt build some full autos SP1 carbines ? Or was this transformed by a previous owner ? The auto sear is missing, and I bought this carbine as a semi auto. Could the sear be installed ? I already have two full auto rifles, an M16A1 and an XM177E2.