Our MRP™ barrel assemblies are unique to the Monolithic Rail Platform system. With the proper installation wrench, an operator can customize his rifle for the mission at hand without armorer or gunsmith assistance. 16" CQB MRP™ barrel assembly, 1:7" twist. Designed for the CQB MRP™ and MRP™ upper receiver. Contact your dealer or LMT directly at 309-732-9527 for estimated delivery time.