AR-15 Barrel Markings

Discussion in 'Technical Questions & Information' started by CountryGunsmith, Feb 23, 2003.

  1. CountryGunsmith

    CountryGunsmith New Member

    Jan 29, 2003
    Deep Piney Woods of East Texas
    Posts: 22
    (12/23/01 8:13:03 pm)
    Reply | Edit | Del All AR black rifle question
    I have an AR rifle with barrel markings C MP 5.56 NATO 1/7.
    does anyone know what the "MP" means?


    Posts: 3092
    (12/23/01 9:40:14 pm)
    Reply | Edit | Del
    Re: AR black rifle question

    All Colt barrels are marked that way, I don't remember
    the meaning of the MP but the NATO 1/7 means 1-turn
    in 7-inches regarding rifling in the barrel, the 1-in-7 is
    the nato standard for using the current issue 62-grain
    steel core bullet, most commercial AR's now come with
    a 1/9 barrel for more bullet stablization and to effectively
    fire most any .223 weight bullets.

    I'm sure someone will be here to give you the meaning
    of the MP and jar my memory lol!
    The Firearms Forum Vietnam Memories Bulletin Board Contact Administrator

    Posts: 1
    (1/16/02 9:19:36 pm)
    Reply | Edit | Del Re: AR black rifle question
    MP stands for 'Magnetic Particle' non-destructive testing...for more detail on "black Rifle" stamping ID see the below:

    Edited by: bondai at: 1/16/02 11:28:27 pm
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