I asked that same question in the early '70s and the answer was 35 grains of IMR 4064 with either a 50 or 55 grain bullet. That was my first centrefire rifle, It was a 788 Remington bought used for less than $100 and had a no name 4X scope on and it came with a bucket full of reloads (that weren't guaranteed but they were accurate an worked just fine), Gary