Gents,
I recently bought a new 11.5" A-2 Commando Upper for my NFA registered lower and I am trying to I.D. the maker.
It is forged, finnished mil-spec, with a heavy barrel, a crush washer and the typical A-2 flash hider.
The receiver is marked on the right side of the carry handle with a keyhole symbol with 3 dots running in a vertical axis. The front sight base is marked on the right side with a C 99, and then a symbol that looks like an R in a circle and the the numeral 1.
The chamber and barrel are both fully chromed.

I have not been able to pull the handguards off to look at the barrel for a maker, chamber spec,and twist rate,as they're very tight and I will have to wait until a friend comes over and use the old "buddy system" to get them off.
I checked both Bushmaster and the S.A.W.(for Colt parts) website, and both companies offer the heavy barrel 11.5" pattern, but Colt also offers a lightweight barrel in this length.

Any help with identification is appreciated!
Thanks,
Mike H.