View Full Version : Colt "CMP" Standard Governmenment Barrel - need info...

January 8, 2013, 10:49 AM
I have an old Colt A2 upper receiver attached to a Colt standard government profile barrel, marked "CMP". Are all AR barrels in high demand right now, or is there something special about these old Colt government barrels that causes them to sell for a premium? What am I missing here?

January 8, 2013, 02:40 PM
The CMP indicates the barrel is chromed and magnetic particle inspected. This is a mil spec barrel and if in spec and not shot out it's a keeper.

Now pretty much everything is a premium on AR parts.

January 8, 2013, 10:23 PM
If the barrel markings are C MP followed by 5.56 NATO the "C" indicates manufacturer (Colt) If the markings are C MP C 5.56 NATO the latter "C" indicates chrome plated chamber. If the markings have a "B" or "CB" after the MP then it indicates both chamber and bore are chrome plated. "MP" obviously stands for magnetic particle inspection. As a rule, most if not all Colt match barrels are never chrome plated being it alters bore diameter. The chrome plating was designed for military rifles to reduce erosion between cleanings.

January 10, 2013, 10:23 AM
I'll check the markings, but I'm positive the bore is plated - you can see the at the muzzle. Also, this is not a match barrel - when I purchased it about 15 years ago, the seller referred to it as a "government barrel".