I just bought a Colt ar-15 that says "Match Target" and "Lightweight" on the lower.

The upper reads:  C MP  5.56 NATO 1/7

What does the "C MP" mean??

Thank you guys in advance.

If I'm not mistaken, it's Colt magnetic particle tested. the B MP on the Bushmasters is Bushmaster magnetic particle.

Exactly what this process is, I don't know. But it's a method for checking the barrels integrity.

Mark

Go to this link and you will find everything you need to know about AR15 barrel and bolt markings.

http://www.biggerhammer.net/ar15/barrelsbolts/

Megnetice partical test is when they take and magnatised the barral and sprinkle iron shavings on it to see if there are any micro cracks in the barral.        i am a AMT student at NMU   we have equipment for  "non destructive testing"    which uses  Partical testing  and a type of testing that uses black light to find cracks,   but thats what the point of this test is,  is to find any defects to the object thats being tested without destorying it

You guys are extremely smart and helpful,  THANK YOU!!!!!

For any gear heads out there, MP is the same process used to check your engine block for cracks.

Match Target is a young rifle that has not molted into an AR15. It will take roughly 324 days 12 hours and 30 minutes for the metamorphosis process to be complete.
After this time period, your Match Target will sprout a flash suppressor and a bayonet lug.  If you treat it well and feed it a good diet of premium ammunition, it will have a long productive life.

When it gets old and cranky, send it to me, I will put it out to pasture.

I was about to ask what the difference was between "Magentic Particle" and "MagnaFlux."

Nothing, I guess. [:D]

Same as the difference between "facial tissue" and "Kleenex"

No.  AR15 was replaced by "Sporter" circa 1989.  Sporter replaced by "Match Target" fall 1994.

Sometimes I think Match and Match Target means they get to raise the price...[;D]

I think politically correct was already taken.

In the case of military markings, and this is per the military prints for the barrel and bolts, the [b]M[/b] is for Magnetic particle testing and the [b]P[/b] is for Proof load testing.

The difference?

MagnaFlux is the name of a company that produces chemicals used in the Magnetic Particle Process of Non-Destructive Inspection (NDI).
[url]http://www.magnaflux.com/index.htm[/url]

Magnetic Particle is the name of a specific type of Non-Destructive method of Inspection for ferris metals.

US Navy Technical Manual
Aviation Structural Mechanic

Magnetic Particle Inspection
Magnetic  particle  inspection  is  a  rapid,  non- destructive means of detecting discontinuities in parts made of magnetic materials. If the part is made from an alloy that contains a high percentage of iron and can be magnetized,  it  is  in  a  class  of  metals  called  “ferro- magnetic,” and it can be inspected by this method. If the part is made of material that is nonmagnetic, it cannot be inspected by this method. The magnetic particle inspection  method  will  detect  surface  discontinuities, including those that are too fine to be seen with the naked eye, those that lie slightly below the surface, and, when special equipment is used, the more deeply seated discontinuities.

CIRCULAR MAGNETIZATION.
Circular magnetization  is  used  for  the  detection  of  radial discontinuities around edges of holes or openings in parts.  It  is  also  used  for  the  detection  of  longitudinal discontinuities, which lie in the same direction as the current flow either in a part or in a part that a central conductor  passes  through.

LONGITUDINAL MAGNETIZATION.
Longitudinal magnetization is used for the detection of circumferential discontinuities, which lie in a direction transverse to or at approximately right angles to a parts axis. Electric current is used to create a longitudinal magnetic field in a piece of magnetic material. When a part of magnetic material is placed inside a coil the magnetic lines of force created by the magnetizing current concentrate themselves in the part and  induce a longitudinal magnetic field.

Magnetic particles may be applied as a dry powder, or wet, by using either water or a high flash point petroleum distillate as a liquid vehicle carrier. Dry powder is available in various colors, so the user can select the color that contrasts best with the color of the surface  upon  which  it  is  used.  Colors  for  use  with ordinary visible light are red, grey, black, or yellow. Red- and black-colored particles are available for use in wet  baths  with  ordinary  light,  and  yellow-green fluorescent  particles  for  use  with  a  black  light. Fluorescent particles are widely used in wet baths, since the   bright   fluorescent   indications   produced   at discontinuities  are  readily  seen  against  the  dark backgrounds that exist in black light inspection areas.