This Bushmaster M4A3 complete upper assembly is chambered in 6.8mm SPC. Simply mount it to a complete AR-15 lower, add some ammunition, and head to the range.

Specifications and Features:
Bushmaster M4A3 Complete Upper Assembly
6.8 SPC
16" M4 profile chrome lined barrel
1:10" twist
Removable Carry Handle
A2 Front Sight
A2 Flash Hider
Carbine length handguards
26 round magazine
Black Finish