This is what 2A Armament says:
 
 
2A Armament is proud to offer our own branded lightweight barrel.  These barrels are manufactured in the USA and are the same barrels that ship with the BLR-16 rifle.

Features and Specs:

    416-R Stainless Steel with QPQ Nitride finish
    5.56 Caliber
    mid-length gas system, .078" diameter gas port
    .625" gas block diameter, 1.1" gas block journal length
    1 in 8 twist
    1/2-28 threads on muzzle
    M4 barrel extension
    11 deg target crown
    Magnetic Particle Inspected
    Weight - 1 lb 3.1 oz