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Rifling Question

Discussion in 'Rifle Country' started by Pony Express, Nov 20, 2009.

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  1. Pony Express

    Pony Express Member

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    Hello everybody,
    I have a quick question about my AR. I'm about to go pick up some ammo and I cant decide which type to get, 55 gr. FMJ or 62 gr. FMJ. It has a 1/7 twist. I always get mixed up which rifling works for which weights, is it the higher the rate of twist the lighter the bullet weight, or the opposite? Thanks, Happy shooting.
     
  2. Avenger29

    Avenger29 Member

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    1/7 twist generally works better with the heavier bullets. Heavier bullets, faster twist (i.e., 1/7 is faster than 1/12). 55 grain will still shoot just fine, but won't often give the best accuracy.
     
  3. rcmodel

    rcmodel Member in memoriam

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    Fast twist = heavy bullet.
    Slow twist = light bullet.

    rc
     
  4. Pony Express

    Pony Express Member

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    Thanks folks
     
  5. wishin

    wishin Member

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    Also, keep in mind that a specific rifle will fire a certain weight bullet more accurately than another with the same twist. I don't know the reason why. I tried various, and settled on the 68 gr with my target mini-14.
     
  6. tominct

    tominct Member

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    With me behind the stock, my Colt Match Target shoots almost as well with Malaysian ball ammo as it does with my 69 gr. Sierra MatchKing handloads. 1/7 twist. I don't know why, but at my NRA Sharpshooter ranking, I wouldn't avoid attending a match because all I had was the military stuff.

    I suppose if I had an Expert or Master classification, I'd notice the difference more.

    I also have a Remington Model 7 (7mm-08) that shoots well with 140 gr. factory loads, and better with handloads, but I can't get 150s to group well with any load I've tried.

    Each rifle is an entity unto itself. Slow/fast/heavy/light generalizations don't necessarily apply to a particular gun.
     
  7. Russt

    Russt Member

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    Keep in mind the length of the bullet comes into play also. The total copper bullets are longer than a lead bullet for the same weight.
     
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