A friend discovered this percussion pistol in her family's belongings. It appears to be .44 caliber. Overall length 7 inches, with a 3 inch barrel. One piece grip, probably walnut. There is a proof mark under the barrel (the pic isn't great, I know) and also someone has etched the Roman Numeral XIII there. Any help in identifying this pistol would be greatly appreciated. Thanks.
Thank you, Jim, for your take on this and for guiding me here.