Barrel length and twist question

Discussion in 'Long Range Hunting & Shooting' started by Rainy, Apr 15, 2019.


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  1. Randy Tidwell

    Randy Tidwell Well-Known Member

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    You are correct Feenix, but the actual weight has noting to do with the it, it is the length of the bullet.

    That is why most shooter talk about twist rate being relative to bullet weight. Conventional bullets get longer as they get heavier.

    If you made a long bullet with a lighter core material, it would still need the faster twist.

    I know I am picking fly poop out of pepper, but when I am looking at twist rate, I am looking at bullet length options, not weight.

    JMHO
     
    Rich Coyle and RYEWSKY25284 like this.
  2. RYEWSKY25284

    RYEWSKY25284 Active Member

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    click on this link;
    kwk.us/twist.html
    this is the formula to get your answer. Or, GOOGLE type in; "barrel twist rate" and lots of info will pop up.
    PEACE!
     
  3. MontanaRifleman

    MontanaRifleman Well-Known Member

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    In other words, a heavy cup and lead core round nose bullet of the SAME length as a lighter, more pointy copper bullet needs less twist to stabilize.
     
  4. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Oh yes it does, it is the caliber AND the length AND the weight
     
  5. MontanaRifleman

    MontanaRifleman Well-Known Member

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  6. MontanaRifleman

    MontanaRifleman Well-Known Member

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  7. thork91

    thork91 Active Member

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    Weatherby’s have crazy long throats for the bullet to jump, how do you make them shoot, just powder charge? How about the new barrel with shorter throat when they ream.? I have 300 WSm vanguard with new barrel and they throated long, mag small ,
     
  8. BallisticsGuy

    BallisticsGuy Well-Known Member

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    Yes it is. Excessive spin exacerbates any mass distribution inconsistencies in the bullet itself which causes group sizes to grow. In extreme cases bullets can come apart from the gyroscopic stresses induced by spinning too hard. There's just no need to twist something for the sake of twisting. It either is or is not stable darned near right out of the muzzle.

    OP: A 12 twist is sufficient up to 180gr bullet from that rifle. Any faster twist only enables you to use heavier bullets if you happen decide you haven't had enough recoil for a lifetime.
     
  9. Randy Tidwell

    Randy Tidwell Well-Known Member

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    Correction to my previous post regarding RPM. I went back to my spread sheet, my memory was off (I'm getting old).

    I entered 3200 fps into the spread sheet, here are the results.

    7.5 Twist 307,200 rpm
    8 Twist 288,000 rpm
    8.5 Twist 271,059 rpm
    9 Twist 256,000 rpm
    10 Twist 230,400 rpm
    11 Twist 209,455 rpm
    12 Twist 192,000 rpm
    14 Twist 164,571 rpm

    Changing the velocity to 3400 fps results in the following:

    7.5 Twist 326,400 rpm
    8 Twist 306,000 rpm
    8.5 Twist 288,000 rpm
    9 Twist 272,000 rpm
    10 Twist 244,800 rpm
    11 Twist 222,545 rpm
    12 Twist 204,000 rpm
    14 Twist 174,857 rpm

    Not sure why I can't upload the spread sheet? But if anyone wants it, just PM with your email address. Or email me at [email protected]
     
  10. Rudolph Ferdinand

    Rudolph Ferdinand Well-Known Member

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    I've been reloading the 300 Weatherby Magnum since 1990. My first hunting rifle Remington 700 Classic w/24” barrel. I saved the bucks and picked up a Weatherby MK5 26” barrel. I have reloaded down to 165 grains Barnes X Bullet recorded velocity around 3500fps, the accuracy was good but I felt that a the heavier bullet would be better, so I've been sticking with 200 grains Buller velocity about 3000fps. The biggest game animal took so far, the Bison here in Alaska a private ranch herd.
     
  11. MontanaRifleman

    MontanaRifleman Well-Known Member

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    To the OP, I'm not sure why you want to shoot a 150 gr bullet, but I can assure you that it is inefficient both ballisticaly and terminally in a 300 Wby. I wouldn't shoot a 150 grain bullet out of a 308 Win. Please don't take this wrong way. Just trying to give you some good advice. There is a reason why so many shoot heavier bullets out of a 300 Mag.
     
  12. Rudolph Ferdinand

    Rudolph Ferdinand Well-Known Member

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    I agree with your bullet selection that there is no reason for using a bullet that lite in the 300 Weatherby magnum. By the way, how is Montana doing these days? I've done two outstanding hunts there for mule deer and antelope, the mule deer 11 pointers and the antelope 14/15” rake. Loved Montana!
     
  13. huntintoo

    huntintoo Well-Known Member

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    32 years of 300 weatherby has brought me to a 168 grn. Barnes TTSX on top of 84.0 grains of IMR-7828. It's my DRT (Dead Right There) go to gun/load for Deer and Elk.
    about 9 Years ago I replaced the barrel with a 26" Schilin and with the Muzzle break is still putin the bullet out at average 3300 fps.
    Built one for a buddy of mine out of the Vanguard and he did not like the recoil and sold it. The same recipe with same results and .27" groups at 100 yards.
    I know the 300 Weatherby was build for 180 Grain bullets but I found these 168 grainers to be the cats meow for my rifle!
     
    Frog4aday likes this.
  14. Rudolph Ferdinand

    Rudolph Ferdinand Well-Known Member

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    The bullets work, use them. The Barnes X-Bullets are all I use in the 300 Weatherby.