I run n-540 and RL-15 I at 600 yards in that bullet weight I have never been able to get the velocities out of varget that everyone else claims to get. Cfe 223 has preformed great with 55's but I'm not sure its slow enough for 77's. Also aa-2520 will kick em out pretty fast but if you live somewhere that gets real hot you will have to work up a summer load and a winter load. My white oak will shoot a 3/4 inch group at 200 with RL-15 and a 77gr match king. I'm not sure what the policy is on posting load data but if you are interested in the recipe send me a private message.