The Hodgdon load center (http://data.hodgdon.com/main_menu.asp
) shows 15 different loads for the 200 grain bullet. Your load is the starting load for your powder/bullet combo.
I use 57.0 grains of W760 behind a 200 Grain Hornady Flat Point. That is near a starting load as well and my notes say the five shot groups are less than 2 inches at 100 yards using peep sights. I tested loads from 55 to 59 grains of W760 and this load was the best accuracy wise. (The notes are 20 years old... boy time flies by fast!)
The gun is the standard model made in 1958, the last year of production with only 220 made after it.