I used RL17 /CCI 450s behind the 123 Amaxes. EXPLOSIVE expansion at distance out of an 8 twist, and impressive velocity. I was close to my H 4350 load, as I recall (work up) 40-41 grains, velocity was 3000-3050 I believe. I will dig around and see if I can find my old notes... It was a slighltly oversize chamber and was getting towards the end of its life. That was 2 barrels ago. It definitely Put the whoopass on coyotes though... softball size exit on a broadside shot @375-400. I have a few boxes left, contemplating making a walking varminter/light hunting rifle and using them for same. Good luck with your adventure. Great bullet (never did buy the hype of melting tips when hornady redesigned the amax line- even moreso with the bullet blowups that are going on with the new design)