Bushmaster's standard barrels are made following Mil-Spec requirements using Mil-Spec materials and finishes (4150 Chromemoly steel).  The only differences between a Bushmaster barrel and, say, a Colt barrel, are:

- Most BM barrels have a 1:9 twist, which is more appropriate for the ammo *most* civilians shoot.  1:7 twist barrels are available in the two common military profiles: 20" A2 and 14.5" M4.

- BM's M4 barrels do not use the Colt M4 barrel extension, which has the extended feedramps.  All BM barrels use the standard barrel extension, as found in all military M16s.

- BM barrels are parkerized as a unit instead of as individual components.  This has plusses and minuses.  The plus is that all of the exposed steel parts will be thoroughly parked and protected, with no assembly scrapes or damage.  The minus is that if you remove the front sight tower, there will be two unparked rings underneath.  Few folks ever switch out their stock FSB, so it's rarely an issue, but if you plan to run something like a PRI flip-up, you may want to have your barrel reparked after removing the old FSB.

-Troy