Upper Receiver Group, Colt MK18

This Colt MK18 upper receiver group has all SA Reliability Package mods.
The MK18's 10.3 inch barrel assy was developed by US SOCOM from the standard Colt M4 barrel.
Not from the M4A1 heavy barrel.  

IN-STOCK.

Bolt Group Upgrade with Charging Handle Assembly

H3 Buffer Assy required.