Lettering on barrel of Colt H-Bar

[762shooter]

I was looking at a Colt H-Bar today. On the top of the barrel between the hand guard and flash hider was stamped "CMP 1/7 " twist". The MP were run together. Anybody know what the CMP means?

 

[LeeEnfieldNo.4_mk1]

Only thing I can think of is "Civilian Marksmanship Program". Probably wrong though, really don't know Why i posted, but before I realized that I have no clue about AR-15's, I already posted, so now I am rambling on about how I have no clue... Off topic

Would be great if we had a program similar to the CMP here. Sell off the old Enfields on the same basis the US does. Oh right, We can't be trusted with 65 year old bolt action rifles, and dont get me started about the .22 trainers... Anyways off topic again.

 

[ESQ]

Colt Magnetic Particle.

Means the barrel is MP inspected. My LMTs are also marked 'MP'

 

[Petrock]

ESQ has it.

There should be a space between the C (Colt) and MP (Magnetic Particle).

My barrel says B (Bushmaster) MP

 

[762shooter]

That makes sense. Yes there was a space between the C and the MP.

Is "magnetic particle" the same sort of thing as Magnaflux testing?

 

[X-man]

It is Colt Magnetic Particle (testing). Same concept as magnfluxing. It identifies any faults in the steel.

 

[BattleRife]

Actually, it's (C)olt (M)agnetic particle (P)roofed

Barrels were test fired with proof loads, then magnetic particle inspected.

 

[recce]

Glad I didn't respond when I saw this post last night. I would have said it meant chrome chamber MP tested but apparently that is an old marking from when not all chambers and bores were chromed.