I just stared using Blackhorn 209 powder in my 50 cal. tc encore with Winchester 209 primers and Hornady 250 gr. sabots. After about 5 or 6 shots, it seems to misfire. I have heard it could be my breech plug. Anyone else having this problem? Any suggestions? I love the easy cleanup and the way it shoots but don't want to have a misfire in the field.