If you are thinking you got a gun that compares favorably to an English side lock, I’m guessing you will be disappointed.
The design is primitive, but, clever in a few of its details. The springs as cocking rods with the rollers built into the ends was actually similar to an English patent, the name escapes me at the moment, but, it was a good idea. My own personal opinion is the area of the frame that is hogged out to make room for the springs, tumblers and whatnot, is material the design can ill afford to lose, and that became an issue when progressive powders came into common use. I’ve seen Tobins with bent frames. A gun that lived in England all its life would likely have seen fewer big number loads, and perhaps will be in good shape. I’m guessing if the design was built of heat treated 4140 chrome moly steel, it wouldn’t be an issue. Americans tended to view their guns as tools, and they were often run hard until they broke.
The Fox is a good American design. So is the New Ithaca Double, or, NID. There are a few that are very reliable, cheap, and charming, but, like a pretty girl with big buck teeth, the Stevens 311, and the Ithaca Lefever Nitro Special come to mind. I hope you enjoy the Tobin, but, just my opinion, it isn’t one to use all the time.
Good luck.
Best,
Ted