Centurion Arms CM4 Set

UPPER RECEIVER DETAILS:

MIL-Spec inner dimension measures at 1.000 -0.0/+0.002″

Thermal Fit inner dimension measures at .997 -0.0/+0.001″ and requires the application of heat in order to provide a solid mate to the recommended barrel extension.  By heat we mean more than granny’s hair dryer.

-For Use with M4 Barrel extensions
-Assembled Upper Receivers come with ejection port cover and forward assist installed

Centurion Arms LLC, C4 5.56 Forged Lower Receiver 7075-T6 Aircraft Grade Aluminum

Receivers Machined from Aluminum Forgings 7075-T6