- RRAGE3 barreled upper receiver (including bolt) in 5.56x45mm
- ARO120 lower receiver build kit (grip plus all trigger, safety, magazine release, etc. parts to complete the lower receiver)
- ARO250D butt stock kit (commercial buffer tube, 1.170″ diameter)
You will need a lower receiver (one of Rock River Arms LAR-15 stripped lower receivers would fit the bill) to build a complete rifle.
Rock River Arms sells 1911 pistols along with complete AR-15 pattern rifles in multiple calibers as well as all the parts you need to build your own AR-15 (upper receiver, lower receiver, barrel, handguard, stock, grip, trigger, bolt, etc.).