light bullet in heavy twist-heavy bullet in light twist?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by JustC, Apr 23, 2003.

  1. JustC

    JustC Well-Known Member

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    Is there a general rule for loading bullets not specificaly in the optimum weight range for a given twist? Let's say a light bullet in a heavy twist barrel,....if you wanted it to group the best it could, would you speed it up or slow it down?

    Also, If you are running a heavy bullet through a light twist, would the opposite be the correct approach?

    I think this is a question of RPM, bearing surface, etc, but that's the best I can ask it. [​IMG]
     
  2. MAX

    MAX Well-Known Member

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    Jugglin' velocity to address marginally compatible bullet lengths and twist rates is not especially productive. Yes it does have some effect but nowhere near what a change of twist will accomplish. 1:12 twist at 3000 fps generates 3000 RPS or 180,000 RPM at muzzle. At 3200 FPs you get 3200 RPS or 192,000 rpm. A 1:10 twist at 3000 FPs gives 3600 RPS or 216,000 RPM. Bullet length is the issue, longer bullets need quicker twists.
     

  3. JustC

    JustC Well-Known Member

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    My question revolves around wanting to load some varmint or lighter bullet loads in some heavier twisted barrels. I asked about 125gr bullet loads for a 30-06 with a 10twist barrel, and quite a few members gave me rave reviews of that bullet in a 10twist, but no actuall velocities for their loads. I was simply wondering, without loading and chronographing the recipes, whether they had slowed them down to get them to stabilize properly. I guess i am looking for a starting point for the future, when I go to work loads for non-perfect bullet:twist combinations.

    thanks
     
  4. Guest

    Guest Guest

    Just C,

    There is no downside to spinning a bullet past what is necessary for stability, unless the bullet is poorly made, or has a large CG offset, then accuracy will suffer. This holds true especially for varmints, because there is not a requirement for a penetration threshold. I can promise you the 30-06 will not spin a 125 Nosler ballistic tip too fast for varmints. We use this bullet in the .308 AR-10's with 51 gr. of Varget and it goes 3,160 fps. It is my favorite short range deer load. Three years ago I shot a 235 lb. whitetail from 20 yards away, broke his right front shoulder bone going in and left a 3 inch exit hole on the opposite side 5 inches behind the left front shoulder. 11.25 was the twist, and 3,180 was the velocity.

    Varget in a 30-06 should easily get you to 3,200 fps. Start at 52 grains and work your way up. If you are a velocity freak, try AA 2520 and you may see 3400 depending on your barrel length. [​IMG]
     
  5. JustC

    JustC Well-Known Member

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    Thanks S1. before I got into the custom stuff, I saw a rugerr 77 MK II stainless 30-06 at an NRA dinner, and just have to have it. Long story short,...the wife won an auction for it without my knowing. Shortly after, I got into the custom arena, and the rifle sat unfired in the safe. Now when I mentioned selling it to help with another project, the idea was not received with the happiness one would expect. Therefore, I am going to make this rifle shoot everything I want it to, and I'm going to have fun with it. I put a boyd nutmeg laminate on it, and I am going to get it spinning those 125gr noslers, and use it for whitetail and whatever else I see in the beanfield.

    The barrel is a 1:10, so I should be OK right?

    [ 04-24-2003: Message edited by: JustC ]
     
  6. Guest

    Guest Guest

    A 1 in 10 will just make the 125 that much more deadly. I have pushed these over 4,000 with a 1 in 11, can't spin them apart with anything I've got (you know I've tried). [​IMG] [​IMG] [​IMG]
     
  7. JustC

    JustC Well-Known Member

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    Thank you for your input S1. You have inspired my interest in this rifle and the 125gr load.
     
  8. jcpython357

    jcpython357 Well-Known Member

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    JustC, You might want to check around on this site to see if anyone has tried the 125 Nosler in their Ruger, have a Buddy that had a Ruger in '06' that would shoot nothing but 180gr roundnose, he tried alot of different bullets to no avail, unless they shortened up the throat on Rugers in the last few years that Nosler may not shoot good, of course there's no guarantee that any rifle will shoot until you try it. [​IMG] J.
     
  9. JustC

    JustC Well-Known Member

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    Thank you Jay. I will check the throat in this rig to see if it is excessive.
     
  10. Cybra

    Cybra Well-Known Member

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    Hey Justin

    Thanks for bring this topic up; I've been doing a lot of contemplating and speculating on this very topic.

    S1 as always, thank you very much for posting what you have. I've been wondering just how "low" I can go with a 6mm project with regard to bullet weight/ The barrel sports a 1:9.33" twist, and was designed almost exclusively with Berger's 95gr VLD in mind. However, I have a couple other bullets I'd love to try; namely the 88gr lowdrag and the 69gr lowdrag. I know the 88 should work just fine, but was a little...concerned about the 69 grainer. If you think this sucker will work... My primary concern would be thinner jackets found on such a bullet, but perhaps that's an unfounded concern? I would NOT be pressing the velocity; like you, I'd be using it for short-range, <minimum noise> applications. [​IMG]

    Dave
     
  11. Guest

    Guest Guest

    Cybra,...

    What are you going to shoot with the lighter bullet you mentioned? Paper? Deer?
    gators?
     
  12. MAX

    MAX Well-Known Member

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    S1 you're a funny guy! You can't shoot Gators here in Florida. Seminoles maybe... [​IMG]
     
  13. Jake in NC

    Jake in NC Well-Known Member

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    ..On the same subject.. The 180gr Nosler BT is looking like fun in the 10 twist 300 Tommy.. Sounds like a true "Quisinart" with good ballistic performance.. Anyone BTDT yet.?

    Cybra.. Just for an FYI.. Me 'ol pal Gene shoots the 87gr VMax's out of an 8 twist 6/.284 with great results..A .4 BC'd frangible bullet at 22-250 velocities makes for an attractive package with ugly results on the 'hogs.. d:^) JiNC
     
  14. Sheldon

    Sheldon Well-Known Member

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    There are a lot of people with 6 BRs set up for long range that are using 55 Nosler BTs on varmints with 1:8 twist barrels. Just go to benchrest.com and you'll see that. No worries dude.