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30 Cal 240 SMK and 1:10 Twist

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  #1  
Unread 05-22-2002, 11:22 PM
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30 Cal 240 SMK and 1:10 Twist

Sorry guys, I know this has been discussed here before but damned if I can find it!

Anyway, I want to try the 240's in my 1:10 twist 300 RUM. Hopefully velocity will be somewhere north of 2900 but I won't know for sure until I try.

Will I have any problems stablizing them?

Thanks
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    Unread 05-25-2002, 01:00 PM
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    Re: 30 Cal 240 SMK and 1:10 Twist

    The program I used to figure it sayes a 9 twist at 2900 and 10 twist at 3000 fps is required. It lookes borderline so I'd do some more research, again, if it were me.
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    Unread 05-25-2002, 01:25 PM
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    Re: 30 Cal 240 SMK and 1:10 Twist

    I have a 1 in 10 twist on the Tomahawk and it works fine.

    Most people shooting the 240 Gr 30 Cal MK do it in a 1 in 10 twist.

    Less pressure and it is very accurate.

    Darryl Cassel
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    Unread 05-28-2002, 01:04 AM
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    Re: 30 Cal 240 SMK and 1:10 Twist

    Thanks guys. I was thinking they might be a bit borderline, but then I kept thinking of all the times I've read, "A bullet will be most accurate when just barely stabilized."

    I think I'll give them a try. [img]images/icons/wink.gif[/img]
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    Unread 05-28-2002, 04:13 PM
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    Re: 30 Cal 240 SMK and 1:10 Twist

    Hello

    10 twist will work just fine for the 240 gr bullet.

    I would however, stick with the 220 gr in the 300 win mag. with a shorter barrel.
    If your barrel was 36" I would say go with a 240 and see how it does.

    Later
    DC

    [ 05-28-2002: Message edited by: Darryl Cassel ]
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      #6  
    Unread 05-28-2002, 11:15 PM
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    Re: 30 Cal 240 SMK and 1:10 Twist

    Darryl, would a 10 twist be okay from a 300 Win Mag or would it only work if velocity were higher? I can get the 220MK going 2900 safely but best accuracy is coming at 2850 or so from my 26" barreled 300 Win Mag. I imagine I could get the 240 going 2750 but accuracy may not be best at max velocity. Rufous.
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      #7  
    Unread 06-08-2002, 03:17 PM
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    Re: 30 Cal 240 SMK and 1:10 Twist

    http://www.accuratereloading.com/76239.html

    Here is something very interesting I saw on accurate reloading.

    Accuracy with 240gr SMK from a 7.62x39mm 1-10" twist. Muzzle velocity between 1790-1900 fps and accuracy from .245" - .872" at 100 yds with 5-shot groups.

    These results kind of lead me to believe just about any .308 bore cartridge with a 1-10 twist will work with the 240gr SMK.

    Maybe the real issue is: at what velocity will a 240gr SMK become unstable if spun at 1-10. Maybe before going subsonic?? I don't know.

    I believe the 300 Whisper uses a 1-8 twist to shoot the 240gr SMK accurately at subsonic velocities.

    MM

    [ 06-08-2002: Message edited by: MontanaMarine ]
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