I also have a Mossburg conversion barrel. Used it to kill my first muzzloader Moose, back about 10 years ago. Shoot good, but I hate that the breech does not come out. Makes it real hard to clean. My Encore and Huntsman, are so much easier to clean, just by removing the breech plug. It's impossible to get all the corrosion causing scum out of the Mossberg barrel. Just look at how hard it is to clean the channel of the breech plugs with them removed. There is no way anyone is going to get all those little recesses clean when the breech plug does not come out.
Plus I hate the old bucket of hot water system. With the breech plug removed, four or five passes with patches and windshield washer fluid and the barrel is clean. Then wash the breech plug with the same stuff, done. It's so much easier than using the bucket of hot water.