I am contemplating build a 7X47L to shoot 140-150 gr. bullets. Berger recommends 1 in 11 or 1 in 12. Barnes tested a 7-08 with a 1 in 9.5. Couldn't find twist rate info for Seirra, Nosler or Hornady.
How do you decide on the best twist for accuracy with a given weight bullet. Is there a formula that involves BC? Or is it based on bearing surface and diameter? Will a 150 Berger require the same twist as a 150 Nosler?
I was thinking 1 in 9 or even 1 in 8, but now think that is too fast and I would be better off with 1 in 10 or 11. I understand the heavier the bullet the faster the twist to stabilize it. But, there must be a rule of thumb or a formula.
Bill
How do you decide on the best twist for accuracy with a given weight bullet. Is there a formula that involves BC? Or is it based on bearing surface and diameter? Will a 150 Berger require the same twist as a 150 Nosler?
I was thinking 1 in 9 or even 1 in 8, but now think that is too fast and I would be better off with 1 in 10 or 11. I understand the heavier the bullet the faster the twist to stabilize it. But, there must be a rule of thumb or a formula.
Bill