03-a3 remington

[Sunray]

U.S. military Parkerizing was manganese based for one. That'd be black. And whoever did it some how missed the last half inch of the barrel too. With a 16" barrel I suspect it was done by 'some guy'. One of the guys on another forum says all of the "bushmasters" were recalled and dumped in the ocean in 1945. There were an unauthorised modification.
No chance the U.S. Ordnance Dept. would make a special run of barrels in the middle of a war. Especially as the Filipino troopies had been using the 1903 with its 24" barrel and 16" bayonet long before there was such a thing as an '03A3. Plus BAR's, Pattern 17 rifles and Thompson SMG's. Philippine Scouts had '03s from 1907.