Our forged upper receivers are a great compliment to our forged lower receivers and are batched either with a MIL-Spec or Thermal Fit bore.

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
-Made in America on American-made machines

*** We recommend gunsmith installation for all of our parts.  We cannot warranty items damaged by improper installation.