The IO Lower Parts Kit 556 M-Lok 15 is everything you need to bulid an AR15 – 5.56 NATO except a stripped lower. The IO upper assembly features a 15in M-Lok Rail. The receiver is a flat top M4 Mil-Spec upper receiver are forged CNC Machined from 7075-T6 Aluminum, the hardest and most durable material of any upper! This 16” .223 / 5.56 barrel is made from 4150 Chrome Moly steel, has 1:10 twist rate & carbine gas system.
|Dimensions||4 × 19 × 3 in|