The rifles you mention are eifled to handle the great majority of "normal-weight" bullets that are loaded in those calibers. Knowing the twist won't help you much unless you have a specialized barrel made for either lighter-than-normal or heavier-than-normal bullets. In addition, there's only one way to determine what bullets work best in your individual rifles is to shoot a bunch of different ;loads, and choose the best one! If you are contemplating taking long-range shots (this is when extreme accuracy is significant), you need a lot of practice anyway, and practicing allows you to test a lot of different loads!!

Keep yore powder dry!!