Unfortunately no formula can take into account proper cleaning and not allowing a barrel to overheat.I put over 1000 rounds through a custom stainless barrel on my 257wby and it would still easily shoot groups under 1/2".I was using 100gr bullets at 3500fps as 3700fps is pushing it.My own barrel had very little freebore which may have slightly limited velocity but did improve accuracy dramatically over the factory barrel.