Results 1 to 11 of 11

Thread: .358 twist rates?

  1. #1

    Default .358 twist rates?

    I ran some data thur a twist calulator and was surprised at the slow rates it came up with for 35 cal bullets.

    I thought a 1:14 was centered for the 225gr jacketed bullets like the partition, a 1:16 for the 200gr pointed bullets like the interlock. Including 200gr RN's at 35rem speeds 2000-2200fps. This leaves the 1:12 for 250 gr bullets and the longer barns coppers.

    My 358win is 1:14 and perfers the 225's over the 200gr spire point for accuracy 2440 and 2500fps.
    My 35 whelen's 1:16 s love 200 CL PSP at 2670fps as does my 336's 1:16 with 200gr CLRN's at 2160fps.

    So for the three main twist rates of 12-14-16 what are they best matched to?

    Twisteds I came up with were 22.0-18.8 for the 225pt and 200sp at 2430 and 2500fps. 10.9 SG was used.

  2. #2

    Default

    Too much theory and formulas for me. I really don't know what twists are supposed to be relative to weight in 35 cal. I will say that my three 358's- a Savage 99, a Win 88 and a custom- all shoot 180 to 275 rifle bullets extremely well, but I haven't tried Barnes coppers. Actually they have done well with pistol bullets down to 125 grains too, though I've never pushed their velocity. If I recall correctly the twist rates on mine are 1:12, 1:14, 1:10. Come to think of it, my 35 Remington is 1:16 IIRC, and it's only marginal in my book with the 220 Speer, but thrives on 200's and 180's.

  3. #3

    Default

    I have 1:14 in both my .35's (a .358 Norma and a .35-30/30) and have not noticed a preference for one weight over another in accuracy.

  4. #4
    Member Matt's Avatar
    Join Date
    Apr 2006
    Location
    Alaska
    Posts
    3,410

    Default

    I thought bullet stabilization had more to do with the length of the bullet and not the weight when it came down to barrel twists.

  5. #5

    Default

    Quote Originally Posted by Matt View Post
    I thought bullet stabilization had more to do with the length of the bullet and not the weight when it came down to barrel twists.
    It does. But presuming the bullets are all of relatively the same material, the heavier they are the longer they will be. Bullets like the TSX with no lead are longer for their weight than a bullet with a lead core.

  6. #6
    Member GD Yankee's Avatar
    Join Date
    Oct 2007
    Location
    PANC
    Posts
    1,117

    Default

    One thing I have read before is that most factory .35 cal rifles have a very slow twist because they're built/based for 35 Remington. But, I would base my ideal twist rate on the actual bullets I plan to shoot most (using the Greenhill formula). Barring that, shoot a bunch of loads and use the best combo accuracy and weight. For me the whole point of the 35 is to shoot a heavy bullet and put a big hole through both sides!

  7. #7
    Member Matt's Avatar
    Join Date
    Apr 2006
    Location
    Alaska
    Posts
    3,410

    Default

    My Norma has a 1/12" twist with a 26" barrel. I'm able to push Swift 225-grain A-Frames at 3,000 fps. Hammer of Thor, for sure!

  8. #8
    Member
    Join Date
    Aug 2007
    Location
    Eureka MT
    Posts
    3,048

    Default

    The twist rate is only part of the eqaution. Bullet stability depends on enough rpm per bullet length. Longer bullets need more rpm to stabilize. More rpm can be aquired by either a faster twist or more velocity or both. A 225gr 35cal bullet at 2000fps from a 16 twist probably won't stabilize. Push it up to 3000 in the same twist and it more than likely will stabilize. My 358 Norma is 1/14" and stabilizes 250gr bullets just fine at 2880fps. I think a formula for rpm per bullet length would probably give a better idea of stability than twist per length. My 2 cents and probably about what it's worth. And of course there's always the one that shouldn't shoot well but does. Maybe it's all just magic.

  9. #9

    Default

    rbuck351,

    Would you be willing to PM me some of your load data for the Norma? I am very curious because I have barely been getting 2800 fps with 225's so the fact that you're doing it with 250's has me intrigued.

    Thanks.

  10. #10
    Member
    Join Date
    Aug 2007
    Location
    Eureka MT
    Posts
    3,048

    Default

    Part of the reason I'm getting that kind of speed is my rifle has quite a bit of freebore so you my not be able to reach that if you have a short throat. I'm at work now and won't give you numbers from memory. Many of the rifles chambered for the 358N were cut with a long throats but not all. A long jump to the rifling can drop pressure quite a bit but it can also adversly affect accuracy. My rifle, a converted P14, has peep and post sights and shoots better than I can see, so pinpoint accuracy doesn't matter much to me. I'll get back with numbers.

  11. #11

    Default

    My rifle has a pretty long throat as well. I can nearly push a 250 gr. bullet out of the neck with my overall length gauge before it touches the lands. I have 4" less barrel than you, but that should only knock off about 100 or so fps. My limited experimenting with 250's has been between 25-2600 fps so I should be higher than that based on your results I would expect. So far I have mostly used 225's. I appreciate any info you can offer.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •