Colt AR-15 SP1 Select-Fire Machine Gun, .223 Rem, Fully Transferable, 16 in Barrel, 4-Position Selector, Carbine Upper
This Colt AR-15 SP1 is a fully transferable select-fire machine gun configured with a four-position selector offering semi-auto, 3-round burst, and full-auto functions. Built on an SP1 slab-side lower with the large two-screw front pivot, it is mated to a slick-side, carbine-length upper and retains classic A1 features including the six-slot birdcage flash suppressor and integral carry handle. It is marked for select-fire with a SAFE/FIRE/BURST/FULL selector legend and includes a carry-handle clamp scope mount.
Condition
Overall Condition: Good condition, showing some signs of prior use and handling.
Bore Condition: Good - Clean, well-maintained, minor wear marks.
Bore Rifling: Good Rifling - Intact, well-defined lands and grooves.
Specific Condition Notes: There are minimal markings from previous handling and use. The bore is bright and clean. A new auto sear has been installed. Refer to pictures.
What’s Included
- Pelican 1750 hard case
- Carry-handle clamp scope mount (installed)
- Two 30-round USGI-pattern aluminum AR-15 magazines
Fully transferable and configured for select-fire, this SP1 features a four-position selector providing SAFE, semi-auto, 3-round burst, and full-auto capability. The receiver is marked SAFE/FIRE/BURST/FULL, and the conversion includes the additional auto sear/axis pin hole above the selector. This setup delivers the full range of functions specified: semi-auto, 3-round burst, and full-auto.
The carbine-length upper is a slick-side design without a forward assist and includes an integral carry handle. A clamp-on carry-handle scope mount is installed. The 16-inch barrel is threaded and fitted with an A1-type six-slot birdcage flash suppressor, secured with a ribbed delta ring. Sighting is via an FSB with an adjustable front sight post and a fixed carry-handle rear sight with a drum and flip aperture; the FSB bears the "UP" marking.
The SP1 slab-side lower uses the distinctive large two-screw front pivot. Receivers are aluminum alloy with a hard-anodized black finish. The rifle operates by direct impingement and uses a selector safety. Furniture includes a fixed polymer stock with a trapdoor buttplate and rear sling swivel, an A1-pattern checkered polymer pistol grip, and round carbine-length polymer handguards. Length of pull measures 13.5 inches.
Chambered in .223 Rem with a 30+1 capacity, this package includes two 30-round USGI-pattern aluminum magazines and ships in a Pelican 1750 hard case. Made in the USA, it presents the classic SP1 profile with the added versatility of a properly configured select-fire system.