I think I have owned about a half dozen Tobins, none were high grade, all were cheap, a few were used very hard, and one was not. I have handled lots of them that I didn't own.
My opinion, after discussion with a pair of English trained gunsmiths, and my own experiences, is, Tobins are an antique design, that was satisfactory when most ammunition was black powder. Using high pressure ammuntion in a Tobin, say above 7-8000 PSI, will quickly render the gun unusable, and unrepairable.
I have seen an off face Tobin, but, much more commonly, the frame bends. Between the cut for the lug of the barrel, and all the material hogged out for the inner workings (the single part carried on the sideplates is the sear spring, the rest is located in deep chanels cut in the frame) there simply isn't enough steel left in the frame to support the gun, when used with modern smokeless ammunition.
Steel shot, as noted above, is pretty much out of the question, again, my opinion based on what I have seen. These are old guns, that are weak, and best for very limited use, in perfect conditions, with ammunition that is gentle to the gun. Like every single American sidelock design I am aware of, there isn't much wood left in the head when the gun is all fitted up, and pushing the limits will destroy the head of the stock, as well.
It is a clever little design, with rollers on the ends of the hammers and the cocking rods, and my 16 was simply a wand, that carried well, and did the job on grouse and pheasants here in the midwest when I did my part.
You will have the only one at the range or in the field. Sometimes, with guns, the market gets it exactly right. If you understand why that is with a Tobin, you can likely keep one shooting for a long time.
Best,
Ted
