Depends on the caliber. Like for a 30-06 and most of the calibers that use .308 bullet and with velocity over 2800fps, 1 in 10 twist is the norm. Bullet wieghts range from 150gr to even 240gr. But when you neck down the 30-06 to a .270 and shoot .277" bullets, and keep the 1 in 10 twist barrel, your optimum grains go from 100gr to 150gr. Reason being is when the bullet diameter gets smaller, and the length of the bullet would get longer for the same grains. And bullet length is a critical factory in bullet stabilization. So they drop the bullet wieght. Then neck down even further to 25-06, optimal goes down to 90gr to 120gr.

But then if you drop the velocity like in a .308Win, you have to loosen up the twist to 1 in 12 or 1 in 14 to shoot the 150gr to 200gr bullets.

So basically, they are all dependent on each other. Velocity, bullet length, bullet diameter.