Hello Woody and welcome to the ALR Forum. If you can post photos it will help us better identify your musket. From what you've said, My guess is that it is a model 1816 US musket manufactured by A Waters (I can't recall off the top of my head where that maker was located). 1830 indicates the year the lock was manufactured, and 1831 the year of the barrel. Hundreds if not thousands of these muskets were sold out of the service to civilians by a company called Bannerman, which often converted them to halfstock shotguns.
Best,
-Eric