I'm not sure staball 6.5 is the right powder for a 223. I have attached Hornadys load data for 5.56mm nato with 20" barrel. I plan to build my gun with a 223 Wylde but have my gunsmith do a longer freebore bades on my longer magazine.Yep. I can't see a 20" running 2700 ever with staball. I'm using hodgdon data.