I used some H4350 during the break in but not any type of load work up .I opted for the RL 16 as a replacement for H4350 in the event I couldn't find any .I've got 12 lbs of it in my closet. LOL. RL16 has been reported to give slightly higher velocities and with the smaller case capacity of the Starline brass, I figured it was worth a shot. I only have 50 or 60 rounds through it so far. I'm having a little trouble with consistent neck tension but I'm about to get it ironed out.