You should probably be looking at using 270 Win Short Mag to form the cases, because the formed 300WSM cases will probably need inside and outside turning.
If the ballistics prove to be just like so many other over bore capacity cases, and you will compare it to the 6mmRem, I think you will find that there will be no appreciable increase in velocity if any. The only area where your new wildcat will probably surpass the 6mmRem is that you will be using about twice the amount of powder to get less velocity!!!!!!!!!!!!!!
