Hello. I bought on old Iver Johnson Hercules some years ago at a gun show. Finally got around to trying it out the other day. Both barrels fired when I pulled the forward trigger. Pulling the trigger on a couple spent shells, showed me that the front trigger has a normal amount resistance to pulling the trigger. The rear trigger has considerably less resistance. It’s more like like the one in my varmint gun, than a shotgun. The gun is in good reasonable condition for its age. Closes tight, doesn’t look like it got dragged down a gravel road, kind of thing. I have done gun repairs before, after finding out complicated it is to do. Not having a lot of luck finding info on this one, tho.
My guess is recoil from the first shot is what set off the second shot, with the light trigger pull. Cleaning and maybe an adjustment is what I likely need.
The gun is stamped with patent dates MAR 16, 1915, APR 27, 1915, on the rib. The only real info I have been able to find is a person claiming the first couple years of production had side plates on the gun (1913-1914), which I appear to have. A bit in the dark about how to safely get the side plates off (remove the screw and tap the gun with a plastic mallet?) and what the trigger assembly itself looks like and how easy it is to work on? Any experiences of someone fixing this sort of problem will be appreciated.
Also, there was mention somewhere about whether it is chambered for 2 ½ or 2 ¾ inch. I shot 2 ¾ shells in the test firing. I don't have any tool for officially measuring that. I can measure with some internal machining tools I have. If the internal diameter in the chamber doesn’t change drastically for the length of a spent 2 ¾ case, can I assume the gun is chambered for 2 ¾ ?