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Thread: Rifle's ideal centre of gravity ?

  1. #1
    Antoni's Avatar
    Antoni is offline There's nothing cushy about life in the Women's Auxiliary Balloon Corps!
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    Rifle's ideal centre of gravity ?

    Looking at picture of a good rifle with mounted scope for sale. It's resting on a narrow box and in balance.

    Butt to trigger blade 74
    Butt to CofG 88
    Total length with moderator 190

    Assuming the total length of the rifle is something like 1 mtetre and scaling, that puts the CofG 460mm / 18½ inches forward of the butt, and the trigger blade 75mm / 3 inches behind the CofG.

    My (fairly heavy) 80K and scope CofG is 480mm / 19 inches forward of the butt and the blade is 120mm 4¾ inches behind CofG. I'd prefer the CofG to be further back than that but that might affect the stability of aim.

    Are there any rules of thumb about these things?
    P1V1overT1=P2V2overT2

  2. #2
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    Are you trying to scale something up from a picture ? or does the picture have nothing to do with the assumptions that follow ?
    Really don't understand what links to what.

    C of G is personal choice, some people like a rifle butt heavy others like it barrel heavy, I like it just in front of the trigger by 110 - 120mm so that it will balance on my leading hand.

  3. #3
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    in terms of accuracy, for a springer, I find about 6" forwards of the trigger blade is optimal...

    Butt heavy guns (like many bullpups), I find have a tendency to wander around on freestanding shots. That's why I'm quite liking my semi-bullpup compatto at the moment.. it's a nice compromise where you want a compact rifle. But rested, or off a bipod, it's not relevant,
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

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    2018 year HW95L

    Quote Originally Posted by Antoni View Post
    Looking at picture of a good rifle with mounted scope for sale. It's resting on a narrow box and in balance.

    Butt to trigger blade 74
    Butt to CofG 88
    Total length with moderator 190

    Assuming the total length of the rifle is something like 1 mtetre and scaling, that puts the CofG 460mm / 18½ inches forward of the butt, and the trigger blade 75mm / 3 inches behind the CofG.

    My (fairly heavy) 80K and scope CofG is 480mm / 19 inches forward of the butt and the blade is 120mm 4¾ inches behind CofG. I'd prefer the CofG to be further back than that but that might affect the stability of aim.

    Are there any rules of thumb about these things?
    CofG = 4.25” in front of trigger blade & 18.25” to center butt with a 14.25" LOP trigger blade to center butt. This rifle is with a Hawke 4-16 x 44 mm Airmax compact scope. I forgot to add that rifle is of course uncocked.

    Last edited by Travis299; 18-04-2024 at 09:48 PM.

  5. #5
    Hsing-ee's Avatar
    Hsing-ee is offline may also be employed in conjunction with a drawn reciprocation dingle arm, to reduce sinusoidal repleneration
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    Quote Originally Posted by Antoni View Post
    Looking at picture of a good rifle with mounted scope for sale. It's resting on a narrow box and in balance.

    Butt to trigger blade 74
    Butt to CofG 88
    Total length with moderator 190

    Assuming the total length of the rifle is something like 1 mtetre and scaling, that puts the CofG 460mm / 18½ inches forward of the butt, and the trigger blade 75mm / 3 inches behind the CofG.

    My (fairly heavy) 80K and scope CofG is 480mm / 19 inches forward of the butt and the blade is 120mm 4¾ inches behind CofG. I'd prefer the CofG to be further back than that but that might affect the stability of aim.

    Are there any rules of thumb about these things?
    My understanding is that a rifle ought to be slightly muzzle-heavy to allow a steady training & aiming on target. The further back the balance point the less stability you’re going to get which is fine if you are in the US Marines and expect to do CQB in your job with lots of rapid reorientation of the rifle, but if you are a sporting airgun enthusiast then deliberate aiming with a slightly weighty muzzle end is going to give the most hits.

    That’s my threppence.

  6. #6
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    Quote Originally Posted by Hsing-ee View Post
    My understanding is that a rifle ought to be slightly muzzle-heavy to allow a steady training & aiming on target. The further back the balance point the less stability you’re going to get which is fine if you are in the US Marines and expect to do CQB in your job with lots of rapid reorientation of the rifle, but if you are a sporting airgun enthusiast then deliberate aiming with a slightly weighty muzzle end is going to give the most hits.

    That’s my threppence.
    I would completely agree if you're on a range shooting at stationary targets, as will having a bipod mounted further forward.
    but for field work where a live target might hop sideways or jump to another branch necessitating a quick change of aim a CoG /PoB further back can be a benefit, as can mounting a bipod closer to the PoB.

    Travis's 95, above looks spot on.

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