Twist rate for .270 WSM and 150-160 gr bullets

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by JARHEAD1371, Oct 18, 2008.

  1. JARHEAD1371

    JARHEAD1371 Well-Known Member

    Oct 9, 2008
    I'm looking at having a .270 WSM rifle built but concerned if the 1-10 twist will be able to stabilize the heavier bullets. Any advice?gun)
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Jun 12, 2004
    Depends on what bullet design your using. IF its the conventional 160 gr bullets such as the 160 gr Partition, the 1-10 would be fine but if your using a custom boat tail design, a 1-9 would be best.

    In reality, one should look at the 270 as the same as a 7mm so what is needed for a 160 gr 7mm in twist would be right for a 160 gr 270. As we know, 1-9 is standard for the 7mm, that may be your best choice if your using a barrel maker that can get you an unconventional twist with not alot of extra cost.

  3. aroshtr

    aroshtr Well-Known Member

    Oct 2, 2007
    I could not get the wildcat 150grn uld to stabilize in my 270wsm that has a 1-10 twist.
  4. Derek M.

    Derek M. Well-Known Member

    Jul 12, 2004
    I had an interesting conversation with Tracy Bartlein just last week about his gain twist bbls. I cannot possibly regurgitate the conversation, and he did state that the jury is still out on this topic, so to speak. But, he's getting reports of lower aggs from some shooters using his 3/4 gain twist bbls.

    In fact, when it comes time to rifle my 6.5 bbl, he or Frank will call me to confirm, but I am interested in trying this rifling. I ordered an 8 Twist. What will happen is he'll calculate a gradual increase in twist (if I recall) from breech to muzzle but I must give him the finished bbl length.

    What will happen is the bore will begin at about an 8.96 twist and at the muzzle will finish at an 8 twist. This will be one of their 5R bbls.

    What you may consider is discussing a gain twist bbl for your 270 WSM. Tell them what the finished length of the bbl will be and have it end at a 9 or 9.25 twist. They will calculate the gain to the muzzle and it will likely begin at around a 10 twist.

    Just a thought.