if you already own an AR-15 chambered in 5.56 or that uses a standard lower receiver assembly for another cartridge, you can buy a 6.5 Grendel upper and install it on your lower.
6.5 Grendel upper works with a mil spec AR-15 lower
if you already own an AR-15 chambered in 5.56 or that uses a standard lower receiver assembly for another cartridge, you can buy a 6.5 Grendel upper and install it on your lower.
6.5 Grendel upper works with a mil spec AR-15 lower