It's a Stevens 59, I would guess a 59 A or B, since it has the black tipped forend, but the pistol grip looks a bit more like a C to me. It also could have been marked a Stevens 39A, or a JC Higgins 101.25. These were all variants of the same model. These were built anywhere from 1938 to 1945, with the C being made from '46 through 1967. I don't think yours looks like a C stock.

It should have a 3" chamber, so it can shoot anything from 2.5" to 3".

That Iver Johnson Hercules is probably a fine shooter as well, assuming it has been treated well. It's not much older, possibly not at all older than that Stevens. The Hercules Grade's were made starting in 1922, discontinued in 1942. I'm assuming it's a .410 as well? If it's a 2.5" chamber, it was made between 1922 and 1935, if it's a 3" chamber, it was made between 1936 and 1942. BUT, if it's in great shape, it might be worth a lot of money for an old scattergun, up to $1000ish.

I had a "Ward's" Hercules in 16ga several years ago, which was made for Montgomery Ward's stores by Iver Johnson. The guy I bought it from didn't know what he had, I bought it for $200 "$100 per barrel" he said... I sold it for $650 after 2 upland seasons. Very slick shooter, knocked down a lot of pheasant with it, almost sad I sold it, other than turning over 200% profit on it.