Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Lighter bullets down a tight twist

  1. #1

    Lighter bullets down a tight twist

    Folks
    I have a 8 twist barrel on order in 6mm flavour.
    I know this will be good for lobbing the heavy pills but I have a urge to shoot something fast and flat at fox.
    Does anyone have any experience of using lighter bullets, say 65 grn to 75 grn in a 8 twist tube.

    Your comments are much valued.
    Alan

  2. #2
    Not in 6mm. I have a 1:8 in .223 and 60 grn is as low as it will go. Needs to be long. I think you can get non metalic expanding bullets which are longer and relatively light.

    Otherwise sorry not a clue.

    D

  3. #3
    Just home load and slow them down so the spin is the correct rate.

    David.

  4. #4
    According to the load data that came with my 6 br, 75 vmax shoot well. I know for a fact however that the 74 pb bullets were awesome and shot some of the best groups I've ever managed consistently. It's an 8 twist btw with 26" barrel and I was using n133!

  5. #5
    Have a look at GS custom Bullets website go to frequently asked questions and look at Twist rates and bullet length. Its bullet length that affects stability not weight. http://www.gsgroup.co.za/faqbullettwist.html

    Slowing the bullet down does not affect the ratio of twist. If the twist ratio in a barrel is one turn in eight inches then that means that the bullet will revolve/spin at one complete revolution for every eight inches travelled no matter what speed the bullet is travelling. So if you have a 24inch barrel then the bullet will make 3 revolutions before it leaves the barrel. However the rate of spin per second will vary with the speed of travel. You can measure the twist rate in your barrel with a cleaning rod and a wire brush, or a patch and take anywhere between one second to 10 seconds if you wished and the the twist ratio will not alter, nor will it alter if you fire the rifle at 3500 feet per second. The rate of spin per second will be very different in each case depending on the speed and I leave it to you to enjoy working out rate of spin per second it will spin in each of the three cases.

    Bob

  6. #6
    Established Poster
    Join Date
    Oct 2009
    Location
    Tokoroa, South Waikato,NZ
    Posts
    160
    I have 2 rifles in 6mmBR 8" twist I have shot 70 grain match bullets through them with good accuracy, some of the varmint bullets tend to blow up when the barrel gets a bit of fouling in them, go for a bullet with a J4 jacket they
    work well in mine, Robert.

  7. #7
    Quote Originally Posted by Bob View Post
    Have a look at GS custom Bullets website go to frequently asked questions and look at Twist rates and bullet length. Its bullet length that affects stability not weight. http://www.gsgroup.co.za/faqbullettwist.html

    Slowing the bullet down does not affect the ratio of twist. If the twist ratio in a barrel is one turn in eight inches then that means that the bullet will revolve/spin at one complete revolution for every eight inches travelled no matter what speed the bullet is travelling. So if you have a 24inch barrel then the bullet will make 3 revolutions before it leaves the barrel. However the rate of spin per second will vary with the speed of travel. You can measure the twist rate in your barrel with a cleaning rod and a wire brush, or a patch and take anywhere between one second to 10 seconds if you wished and the the twist ratio will not alter, nor will it alter if you fire the rifle at 3500 feet per second. The rate of spin per second will be very different in each case depending on the speed and I leave it to you to enjoy working out rate of spin per second it will spin in each of the three cases.

    Bob
    The bullet will do one revolution for the length of twist but the speed of rotation is dependent on how long it takes to to travel that distance. If it takes one thousandth of a second to travel one full revolution it wil be rotating at one thousand revs per second, 0ne two thousandth to travel the same distance it will be rotating at two thousand rev per second. It is just basic physics.

    David.

  8. #8
    Quote Originally Posted by robertw View Post
    I have 2 rifles in 6mmBR 8" twist I have shot 70 grain match bullets through them with good accuracy, some of the varmint bullets tend to blow up when the barrel gets a bit of fouling in them, go for a bullet with a J4 jacket they
    work well in mine, Robert.
    Thanks for the feed back.
    I may try some mid weight bullets like 75 grn Vmax - even 70 grn BK's
    I cant see them tearing apart at sensible velocities.

    Gents - Thanks for your input - keep it comming

  9. #9
    As per my original post, it will need to be of a long design. Also if looaded too quick could well over spin so will self destruct in flight. Thats why the non copper alternative may be the way forward as long, light and dont self destrust.

    Why not PM Laurrie Holland who may shed more light on your question.

    D

  10. #10
    David,

    I quite agree

    Bob

Similar Threads

  1. .223 lighter bullets
    By chickenman in forum Ammunition, Reloading & Ballistics
    Replies: 9
    Last Post: 21-10-2011, 21:09
  2. Twist Rates - how to find what your twist rate is:
    By deeangeo in forum Ammunition, Reloading & Ballistics
    Replies: 0
    Last Post: 20-08-2011, 06:29
  3. How tight is too tight when seating a bullet?
    By stuey in forum Ammunition, Reloading & Ballistics
    Replies: 12
    Last Post: 15-12-2010, 05:54
  4. How tight is too tight - bolt
    By 75 in forum Ammunition, Reloading & Ballistics
    Replies: 18
    Last Post: 14-04-2010, 12:56
  5. Lighter bullets.
    By basil in forum Deer Stalking General
    Replies: 5
    Last Post: 22-03-2009, 16:46

Posting Permissions

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