Keeping your muzzleloader clean is often key to the accuracy, performance and longevity. Failure to do so can result in misfires, corroded parts and wasting money on a problem that could have been prevented.
Cleaning your barrel after each shot is often the first step to ensuring accuracy on a shot-to-shot basis. Because muzzleloaders burn powder at a slower rate than centerfire rifles, excessive fowling inside the barrel can prevent a consistent bullet seat. Avoid this by running a patch soaked in solvent followed by a dry patch when sighting in at the range. Although necessary for consistent performance at the range, shot-to-shot cleaning is only the beginning of proper firearm maintenance.
After shooting, removing and cleaning the breech plug is extremely important. If overlooked, the breech plug can corrode and seize to the barrel. Once removed, wipe the breech plug with a cleaning patch soaked in cleaning solvent, and then pick any fowling from the inside of the plug with a nipple pick or stout needle. Removing the residue or fowling near the primer will lead to cleaner burns, quicker ignitions and fewer misfires.
Finally, coat the breech plug with a liberal amount of breech plug grease and screw back into the gun, making it easier to remove and clean in the future.
Make your muzzleloader easier to load by conditioning the barrel with a product such as Thompson Center's Bore Butter. After you have cleaned and replaced your breech plug, run one patch coated in Bore Butter thoroughly up and down the barrel, coating the inside completely. By doing this, you are essentially greasing your barrel and making it easier to slide your projectile of choice completely down it. Over time, loading will require less effort and bullets will seemingly glide into their seat.
Finally, consult your firearm manual to remove and clean the trigger assembly. Wipe the assembly clean of any residue and fowling with a dry cloth and re-install into the gun. If possible, store the gun horizontally or with the muzzle facing down. By storing it horizontally, all lubricant will be prevented from running into the breech and leaving the barrel unprotected. Storing a muzzleloader barrel down will ensure dust and other foreign particles cannot contaminate your clean weapon.
Always review your firearm manual for tips and suggestions offered by the manufacturer. Never store your firearm without cleaning, as doing so can deteriorate its quality quickly.