If the breechplug has not been removed for that long a period and using Pyrodex which is very corrosive I would be very concerned that the barrel is corroded enough to cause a problem with possible dangerous results (like a barrel rupture that has been reported with CVA barrels). Personally I would send it back to CVA or scrap it. I would not recommend shooting the rifle any more until checked out by someone that knows what they are doing. If the barrel ruptures while shooting it will likely cause severe damage to the shooter including death. Please do not shoot it until checked out we do not need anymore reports of barrel rupture.