The .223 likes the same powders as the .308 Win. I use BL-C2, RL15, Varget, N140, CFE223, and others are good performers. What bullet weight are you going to shoot? I take it you have one of the modern 1:9" twist barrels? You can shoot up to 69-70 gr bullets. Which bullets depends on what you want to do. Paper punching, varmint/predator hunting, long range, etc. What cases do you plan to use?