CVA Optima Magnum .45 cal load help!

[Lnewton]

Picked this up a couple of months ago to try my hand at muzzle loading. So far I have only shot 8 rounds through it. 3 powerbelt 295 ELRs with 110 grain by weight of 777. I have also shot 5 Hornady 200s with the same 110 grain by weight 777. Shot OK, like 2” at 50 yards with both loads but 100 yards was all over. This rifle is set up with open sights for a New Mexico Mule Deer hunt so I have that to contend with as well. Any load data with 777 only would be appreciated. .45 projectiles are not very available either. The ELRs are at my local academy but had to get the hornadys at scheels 2&1/2 hours away. Any help would be greatly appreciated.