The300(BEE) is great started out useing Imr4831 worked great with165 Barnes bullets for elk , never needed the heavier bullets. Years later tried RL/22 worked just as great . Took 6 or 7 elk to finally catch one bullet and that was 180 blu XLC Barnes that took a medium 5x6,or 5x5 but 99% have been taken with the 165's , factory brass (wby) is great (r-p) ok but smaller inside volume for powder .loaded for 2 rifles one push W/md70/24 inch bbl ,one Vangard 24 inch bbl both 1/10 twists . One supposed newer powder that's worth trying is Imr7828 but that's old news that's dated .......each his/her own takes Reading research n Reloading to find what works but that's easy if you've got the passion for it !!! I'll ad H1000 is Great powder but so is RL/25,RL/26 Enron/IMR 7977 ,(H)Retumbo manny great choices . Cheers!