A musket (long gun,aprox. 69 caliper) converted to precussion, from the time frame early 1820's from 'Johnson Midd Conn'. I know there was a maker Robert Johnson in Middletown, Ct. Can you tell me anything about him? Volume of guns produced. How rare and desireable are his guns. If not R Johnson maybe (J) any other info. How much, if any, does a plain patch box add value to this type of gun? Does the type of conversion to precussion make a difference? Where, other than google and this site can you obtain information? Thank You.