Double check my math, but this should be pretty close or possibly help you out some.
You are getting weights from 77 to 84 grains with a 100 grains by volume. Let’s average that out to 80.5 grains of volume per 100 grains in weight (77 + 84 = 161) (161/2=80.5).
80.5 / 100 = .805 grains of volume to 1 grain of weight.
100/.805 = 124.23 (rounding) grains of weight to equal 100 grains in volume (double check 124.23 * .805 = 100.005)
Definitely double check this, I did the math in 30 seconds in my head.
I personally have not had any consistently shooting pellets out of my CVA. I use Triple 7 powder at 90 grains volume with 245gr powerbelt and I am having a lot more consistency.
Good luck and keep us posted on how/what your results end up!