i was wondering what types of shotguns was the most popular and widespread in the old west.
(lets say ca 1870-ww1).

it would be of great help if you could name some of the most popular models, so that i can google them myself.

thanks.

I would try the Antiqueguns shotgun forum. http://www.antiqueguns.com/phorum/list.php?10 From 1870 you are going to get mostly doubles shooting black powder. In 1887 Winchester made the first successful repeating shotgun. It was a lever action designed by John Browning. The other significant repeater of the time frame you mentioned was the 1897 Winchester pump gun, also a Browning design. There were a lot of repeaters made after the turn of the century like the Rem 11 and the Win Model 12

Still the shotguns of the settlers and the old west would much more likely have been a SxS black powder double or a single shot and likely as not would have been a muzzle loader.

By far the coolest one was this, but there weren't a lot of them.