7mm-08 Twist Question

Discussion in 'General Discussion' started by RedRaider, Feb 23, 2011.

  1. RedRaider

    RedRaider New Member

    Nov 28, 2010
    I am building a 7mm-08 rifle and need some help with twist rate. I need to say that this will not be a long range rifle. This will be a 100-300 yard rifle with a Brux barrel and Predator action. It will be 21" long with a #6 contour.

    I will never shoot a bullet heavier than 140 grains (I have other guns for bigger bullets). I will primarily shoot the Barnes 120 grain ttsx bullets (1.217 inches) and expect to get about 2850fps with the 21" barrel. I might shoot the 140 Barnes ttsx bullets which will be around 1.325 inches in length. Both of these bullets are slightly longer than similar weight bullets from other brands. If I shoot the 140's, I expect 2700 - 2750 fps.

    I don't want to spin these bullets to fast and possibly affect accuracy. I also might pick up a little speed (not a lot, but maybe a bit) with a slower twist. I was thinking a 1:9.5 twist for this gun, but as I plug it into calculators (JBM Ballistics), it appears a 1:10 would keep the bullet stabilized (it actually says 1:11 would just barely stabilize the bullet, but not the 140 Barnes).

    Anyone out there have some advice for me on this build? It would be greatly appreciated!
  2. Deans

    Deans Member

    Jul 10, 2008
    I have a Ruger MKII 7-08 with 1:9.5 factory twist. I am working up a load with the Barnes 140gr TTSX and getting good accuracy @ 100yds for an Elk hunt. I need to do some tweeking but expect good/excellent accuracy out to 300-400 yds if I do my part. Hope this helps.