Receivers Machined from Aluminum Forgings 7075-T6
Upper Receiver 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.
For Use with M4 Barrel extensions
We recommend gunsmith installation for all parts. We cannot warranty items damaged by improper installation.
