Just a guess mind you. When I shot 777 with patched ball I had to put a wad under the patch our it would destroy the patch. Accuracy was still great but the patch was blown. That's because 777 runs hotter and with more pressure. Now I am not saying that is the reason. Its just a ... what happened to me.

Also the more fouled the rifle becomes it can lead to a tighter bore, and maybe that had some effect on it. Hard to say. If the accuracy was good, I wouldn't concern myself. But if you want ... and have no wad, try taking some cotton patch, roll that up. After you dump the powder 777 then push that patch down first on the powder. See if it helps.