Any Insiders Know Why the Competition -M Upper Is So Short?
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Thread: Any Insiders Know Why the Competition -M Upper Is So Short?

  1. #1
    XCR Guru Sean K.'s Avatar
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    Any Insiders Know Why the Competition -M Upper Is So Short?

    Why does the -L comp upper cover the majority of the 16" bbl while the -M version really only covers the 14.7" length?

    Anyone know the reasoning? Was it just the extra weight?
    "Necessity is the plea for every infringement of human liberty. It is the argument of tyrants; the creed of slaves."-William Pitt the Younger

  2. #2
    XCR Guru Sean K.'s Avatar
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    Guess not.

    Kind of kicking around the idea of cutting up one of my quad rail -M uppers and welding it to a KM stnd. length upper to make a "comp" upper that actually covers a 16" bbl. Obviously, I'd have to machine off the side rails....I'd likely blend/machine/transition to leave like a 3 slot or 5 slot bottom rail for mounting a bipod...then cut KM slots and Durakote or similar the upper.

    Just measured it up....looks like adding 4.75" is about perfect. I'd have to machine a channel in the web in that new section of rail to clear a Type 3 buried block.

    Hey Nate, if you read this...do you know if the non-accurized Type 2 gas block is interchangeable with a Type 3?
    Last edited by Sean K.; 06-23-2020 at 08:19 PM.
    "Necessity is the plea for every infringement of human liberty. It is the argument of tyrants; the creed of slaves."-William Pitt the Younger

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    XCR Guru navalbeaver's Avatar
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    Quote Originally Posted by Sean K. View Post
    Guess not.

    Kind of kicking around the idea of cutting up one of my quad rail -M uppers and welding it to a KM stnd. length upper to make a "comp" upper that actually covers a 16" bbl. Obviously, I'd have to machine off the side rails....I'd likely blend/machine/transition to leave like a 3 slot or 5 slot bottom rail for mounting a bipod...then cut KM slots and Durakote or similar the upper.

    Just measured it up....looks like adding 4.75" is about perfect. I'd have to machine a channel in the web in that new section of rail to clear a Type 3 buried block.

    Hey Nate, if you read this...do you know if the non-accurized Type 2 gas block is interchangeable with a Type 3?
    To my knowledge, it's not a direct replacement. Pretty sure you'll need the appropriate tube and piston head/op rod to make the swap. Also not real sure how compatible the old/new gas tubes and gas blocks play together if you don't have a "matched set"
    Last edited by navalbeaver; 06-23-2020 at 10:12 PM.
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  5. #4
    XCR Guru Sean K.'s Avatar
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    Quote Originally Posted by navalbeaver View Post
    To my knowledge, it's not a direct replacement. Pretty sure you'll need the appropriate tube and piston head/op rod to make the swap. Also not real sure how compatible the old/new gas tubes and gas blocks play together if you don't have a "matched set"
    That's what I was afraid of.

    Had a feeling this isn't really worth doing without buying a new upper, bbl and Type 3 gas system....and my Type 2 non-accurized is actually really accurate so messing with it is probably a bad idea.

    Just not sure why RA doesn't make the -M "comp" model like the -L where the upper actually shrouds a 16" bbl.

    Oh well, no biggie.
    "Necessity is the plea for every infringement of human liberty. It is the argument of tyrants; the creed of slaves."-William Pitt the Younger

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    XCR Guru TomAiello's Avatar
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    To turn the question on it's head, why are the competition uppers so long?

    I have zero knowledge of competitions, so I don't understand why you'd want them longer for that.

    Maybe someday, when I have more spare time in my life, I can get into competitive shooting and find out.
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    XCR Guru TexasChris's Avatar
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    Quote Originally Posted by TomAiello View Post
    To turn the question on it's head, why are the competition uppers so long?

    I have zero knowledge of competitions, so I don't understand why you'd want them longer for that.

    Maybe someday, when I have more spare time in my life, I can get into competitive shooting and find out.
    I've shot a whopping, entire, 3 gun match......so......


    My guess is that the longer uppers make barricade work and shooting from concealment/cover easier. More to prop, shove, wedge and jam.


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    XCR Guru Sean K.'s Avatar
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    Quote Originally Posted by TomAiello View Post
    To turn the question on it's head, why are the competition uppers so long?

    I have zero knowledge of competitions, so I don't understand why you'd want them longer for that.

    Maybe someday, when I have more spare time in my life, I can get into competitive shooting and find out.
    I think it has more to do with gripping the gun as far out as you can to drive the muzzle without overshooting (pardon the pun) the target.
    "Necessity is the plea for every infringement of human liberty. It is the argument of tyrants; the creed of slaves."-William Pitt the Younger

  9. #8
    XCR Guru TomAiello's Avatar
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    How much heavier does it make the rifle, on the whole?

    The older I get the more I appreciate lightweight gear.
    - Tom Aiello
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  10. #9
    XCR Guru Sean K.'s Avatar
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    Quote Originally Posted by TomAiello View Post
    How much heavier does it make the rifle, on the whole?

    The older I get the more I appreciate lightweight gear.

    Since the new section would only be ~1.75" vs. the current "comp" -M Upper...probably only 2 oz. or so.
    "Necessity is the plea for every infringement of human liberty. It is the argument of tyrants; the creed of slaves."-William Pitt the Younger

  11. #10
    XCR Guru fmunk's Avatar
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    Ounces turn into pounds with each mile.
    Fool-proofing serves only one purpose: identify bigger fools.

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