H4831 is really slow for .223 Rem, even with an 80 grain bullet. Speeds produced will be low. You'll need a case full of gunpowder. I wouldn't be surprised if the brass would not seal the chamber in the rifle.
Buy another .270 or a .30-06, or trade the H4831 to someone for some Reloder 15.
By the way, I'm not recommending you load with a case full of H4831 gunpowder.