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1-12 rate of twist

ndbillyndbilly Member Posts: 1,573 ✭✭✭✭✭
edited August 2002 in Ask the Experts
Remington Model 7 Youth, 20" barrel in .223. Is 1-12 the optimal rate of spin for this round, assuming military load specs.?
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Comments

  • JustCJustC Member Posts: 16,056 ✭✭✭
    edited November -1
    If you wish to use 45gr-52gr bullets, then yes. If you want to use 55gr-75gr, then no. Of course you could handload and play with powder charges and get any weight to shoot in that twist, but the velocity will be way off one way or the other.

    A great rifle with a junk scope,....is junk.
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  • leeblackmanleeblackman Member Posts: 5,303 ✭✭
    edited November -1
    I'd say its ok with 55gr and under. If anything, you'd want either a 1 in 9 or a 1 in 8 twist rate for longer 68-75 gr bullets. Personally I'd want an exact 1 in 8 1/2" twist rate.

    If I'm wrong please correct me, I won't be offended.

    The sound of a 12 gauge pump clears a house fatser than Rosie O eats a Big Mac !
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  • ndbillyndbilly Member Posts: 1,573 ✭✭✭✭✭
    edited November -1
    Thank you, gentlemen. I see a lot of surplus stuff out there in the 52/55 gr. range.
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  • nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    According to Shilen's barrel making site, bullets of 63 grains and lighter will be suitable in a centerfire 22 caliber with a 12 twist.
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  • v35v35 Member Posts: 12,710 ✭✭✭
    edited November -1
    The optimum rifling twist rate for the .223 is 1 turn in 8 1/2".
    I believe the importance of twists tighter than 1 in 12" shows up in improved accuracy beyond 200 yards with bullets 55 grains and heavier.
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  • nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    I would be very interested in reading the research that states that the 8-1/2 twist is optimum for the .223 cartridge. I'm always looking for new information to add to my files. Please let me know where this is available online or in print.
    Thank you.
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  • v35v35 Member Posts: 12,710 ✭✭✭
    edited November -1
    Nononsense- Pose your question on www.ar15.com
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  • nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    Just for the sake of discussion, I thought that it would help to clarify a couple of points.

    The question was really asked in 2 parts:

    - "Is 1:12 the optimal rate of spin for this round, assuming military load specs?
    No, since the military has several loads for the .223 as used in the M-16 with weights that range up to 80 grains which requires a 1:7 or 1:8 twist for stability.

    - (Is a 1:12...) "I see a lot of surplus stuff out there in the 52/55 grain range"
    No again, based on the ballistic information published by the bullet manufactures themselves regarding their bullets. The optimum twist for the 52/55 grain bullets in the .223 cartridge is 1:14. The 1:12 twist will stabilize up to the 63 grain, non-VLD bullets in a .223 cartridge.

    The super accuracy people will tell you that they achieve best accuracy when shooting bullets in a twist rate that just barely stabilizes the bullet of a given weight. It's not that a faster twist can't be used, but the accuracy is higher when the twist is minimal based on bullet weight.

    My .223's are 1:14, 1:12, 1:8 and 1:7 in bolt rifles. My AR's are 1:7 and 1:14 since I want to shoot both the very heavy bullets in one and very light varmint bullets in the other.
    Regards.
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