I shoot a compound set at 70# and want to build a carbon arrow with about 300 grains up front.Wanted to know if a 340 spine would be good?
It depends on the draw length. Using a brass insert instead of the normal alum. Will help you reach your goal. This link you help you (and others) better understand weight forward FOC and the benefits in penetration. http://www.alaskabowhunting.com/PR/Ashby_EFOC.pdf