M4 LE6921 Upper Group 14.5in Stripped
Cartridge: 5.56 mm NATO
Muzzle: 1/2-28, ...
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Add the Colt legend of reliability to your rifle or build with these complete upper receivers from Colt. These Uppers are based off the combat proven M4 upper receiver and feature 1/7 RH twist in a chrome lined, button rifled barrel. Available with a 16”, 14.5” or 11.5” barrel. Available with or without a charging handle, bolt carrier group, and back up sights. All NFA rules apply.
AR-15, Issue:11, Page:003
Big Book Catalog, Issue:72, Page:003