Some folks just find pellets to be inconsistent while they work fine for others.
It's the same with sabots and certain guns.
You can switch the powder and see if that helps or switch to another projectile.
The 777 Magnum pellets are like loading 120 grains of Pyrodex. That's not necessarily bad but how can you adjust the load?
Moisture can be dried out of a barrel by swabbing with each side of a dry patch, and swabbing with 92% alcohol in between cleaning & drying swabs can also help to remove moisture if that's the problem but I sort of doubt it.
I'd hate to think that it's back to square one but here's some useful info. posted by Kodiak users:
http://huntingnet.com/forum/black-po...va-kodiak.html