In the end that bullet may just not work in that gun. But first a few checks before giving up on it. Did you notice if the holes in the target were perfectly round indicating stability or lack of? I use the PB 295 AT and HP in my flinter (1:32) with 90gr of 3F 777 and get very good accuracy. That dosn't mean you will in your gun but from a charge perspective I think we are probably very close. I think pyrodex is very close volume wise to real black 2F so my 90 of 3F 777 is probably pretty close to your 110 of pyro, add 10% for the 777 and then some more for the 3F granulation, must be real close to a 110 pyro charge.
How easy or hard is it to load? Hard? if you're using the 295 Aerotip what ramrod tip are you using, any chance you're deforming the tip? Easy? any chance the bullet is moving off the charge because it is too loose? Should be a firm push, not hard or easy.
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