Firstly, the S/N list is very approximate as Scott was building 2000 guns per year, which is a pretty astounding rate of production of handmade guns in a year's time, but they were the biggest English gunmaker. Secondly, the muzzleloaders were produced concurrently with the breechloaders from the late 1860's on and each type was numbered in a 1-10000 range, so you could have two different guns, one a ML and one a breechloader, with the same S/N. Regards, Sandlapper