I have a Winchester pre-64 Model 70 in 300 H&H Magnum I hand load for. It is extremely accurate with 69gr Norma MRP and Hornaday 150grSPBT Interlock. It came with a vintage 1950's Weaver K6 scope euro-style postreticle. I want to go to a heavier bullet for hunting elk without loosing accuracy. What bullet weightwas the rifling designed for? What's everyone's personal preferance for bullet weight?