Bulldog,

Twist affects stabilisation of a bullet and to an extent determines how heavy
a bullet can be used. Re read articles on the 6mm Rem / .243 from years ago
as Remington got the twist wrong and Winchester got it right (with the 243).
It all had to do with Stabilising heavier bullets.

There are formulas for woking out the best twist and someone else here
is probably much better qualified to write about it.

500 Nitro