rifling twist for 45-70 0r 450 marlin

[dragonrider]

I am planning the build for my 458 bolt gun, am planning on using boolits of 300-425 range, heavier boolits are way too tough on old shoulders. Would like suggestions on twist rate for the above mentioned boolits. Douglas offers rates of 14 to 22. Shilen offer only 14. Cast boolits of course. Also barrel length. considering 26 for a minimum but thinking 28 would be better. Any other suggestions are welcome.
Thanks

[SharpsShooter]

I am planning the build for my 458 bolt gun, am planning on using boolits of 300-425 range, heavier boolits are way too tough on old shoulders. Would like suggestions on twist rate for the above mentioned boolits. Douglas offers rates of 14 to 22. Shilen offer only 14. Cast boolits of course. Also barrel length. considering 26 for a minimum but thinking 28 would be better. Any other suggestions are welcome.
Thanks


If you have samples of the boolit, you could use Greenhills formula to determine the optimal twist rate. PM me the length of the boolit and i'd be glad to calculate it for you. It will likely fall into the the vicinity of 1:18 for those weights. I am curious as to your choice of barrel length. Given the fact that you will need to use a long bolt action, adding 26" to that would start you out with around 32 inches overall. Factor in around 13 or 14 inches for butstock and it has grown to about 45". Thats a fairly long barrel for smokeless IMHO.

:coffee:

[felix]

22 twist is plenty for those boolit weights/lengths up through 300 yards plus. ... felix