Bob,

Nice link. Here is a picture of a replica Colt 1878 12ga and the finished movie version of an 8ga.



Here is the description of the process with pictures.
http://www.imfdb.org/index.php/SK_1878_shotgun

I have an 10ga Colt 1878. There is no way I would want to lug it around all day. Certainly not an 8ga. frown




Pete