It seems you have stumbled upon one very good reason to have a breech plug with a removable vent. The vent can also be removed for easier cleaning. Replacing the vent instead of the whole plug will save you $$.

Photo show the plug from my mountaineer after it was converted to utilize a removable vent.







I cannot comment on accuracy, because i have never ever shot through a breech plug with a orifice larger than 0.035".