When I first built my .35 Whelen about 15 yrs. ago, I read everything I could get my hands on regarding loading for the Whelen. Based on my research, I chose IMR 4064 as my powder of choice. I loaded it behind bullets from 200gr. to 225gr. in a variety of charge weights. My range testing showed that the .225gr. bullet produced the smallest groups in my rifle. In '08 I took an 8pt. whitetail, a double lung shot at 100 yds. yielded a blood trail a blind man could follow and a dead deer after approx. a 30yd. death run. Research subsequent to that hunt has shown that here on the Campfire the are several .35 Whelen shooters who have had fine results with RL-15. My next session at the reloading bench I will be utilizing that powder.
