Not sure if this will get you to 2800 but in my service rifle 77gr. smk you can use 23.8 to 24.5gr. of RL-15. go low at first and then work your way up.
23.9 grains Ramshot TAC is a top load for velocity and accuracy in my AR 1/8. Not sure of the velocity. Work up as this is near the max of 24 grains. Measures very well out of a Harrell.