Long Tom 12G
136" barrel! I read how the super length barrels were a benefit for black power but not so much for the smokeless. The benefit was extra oomph and a little more distance.
The forcing cone taper is very slight. I don't know what to think about that. Reading up on older guns I saw some warnings that cones designed for brass shells did not need room for the shell to expand when fired. Without this extra elbow room a modern shell could be too tight.
As for maker, there seems to be 2 major companies, Crescent and Meriden from about 1880-1930, that cranked them out with store name brands. Little to no records exist to track down specific time or place of manufacture.
Puffing up is no substitute for smarts but it's a common home remedy