FWIW, the rifle photo posted in the OP is the Pedersoli Country Hunter which is made in both flint and percussion. According to the Pedersoli website, both versions have a 28 3/8" barrel, weighs 5.73 pounds and has a 1 in 34" twist.
It's sold at Cherry's Fine Guns:
http://www.cherrys.com/ped_rif2.htm