Have you given much though as to what style you want to go with or time period??? In the 1770s a Lancaster or Christian Springs would be nice...Later (1800) the rifles became slimmer and calibers smaller, that's where you go with the Southeast VA and TN rifles in .32-40 caliber with the cresent butt plates...

Still later (1850), you get into the Hawken era,with bores .50-.54 and the move to percussion guns, or the Vincent rifles out of Ohio, they were usually .36-.45 caliber...

So you might want to give some thought as to where your ancester's came from, if that's important to you, or what type hunting or target shooting you want to do...