We all fall into the mistaken premise that if an individual advertises them self as a gunsmith then they know all about our black powder guns.
Not the case.
I took a gun to a well known and respected(locally) gunsmith that specializes in building really fine rifles. I came out of it with 300 miles of travel, $135 in expenses and a ruined rifle barrel.
It cost me over $200 to learn my lesson. Do your homework before you assume he has done his.
I study a little and do the majority of my gunsmithing myself.