Most likely the charcoal difference they use.

I even found my old reports about accuracy and how dirty the shutz was. I had been using mrflintlock lube and the balls were getting caught up in the fouling during reloading. Thats not clean powder.

All the right hand shots were with the rifles normal load and shuetz powder. Thats not accurate at 50 yards. Even in my rifle, anything over 90gr wasnt worth the lead.