I am getting set up to load 338wm which is my first belted case. I was told not to use a FL die? Which dies are best? All I can find locally are RCBS FL. Also I am gonna be loading some Hornady #3310 200gr sp-rp interlocks. What powder would uield the best results? I have loaded. 308 in the past but normally only load handgun and I am totally new to magnums.