I have not played with 69's too much. But i remember clearly when i did, 25.5 - 26.0 grains of W748 in WW cases shot really well from my 24 inch barrel. Seemed they liked to go just north of 2900 fps or so.
It seems in 223 Rem and 308 that if your barrel likes the bullet, it will shoot good with any reasonable powder. Powder will change the accuracy window and the velocity that window is in. To a point.....
