1939
If it indicates that it will accept a 3 inch shell, it is a magnum. If it is marked 2 3/4 inches, it is not. Unmarked- not.
When were 3inch magnum
An Ithaca model 51 magnum 3 inch shotgun is worth $275-$325, depending on condition.
The longest shotgun shell that you can safely use in your 12 gauge shotgun are 3 inchers.
Yes, they are all high brass and considered magnum loads
Yes
Yes you can you can shoot 3 or 2 and a half in
The 12 g Marlin 200 single shot shotgun SHOULD be marked on the barrel, something like "model 200 12 g 3" Modified" That means it will fire the 3 inch magnum shotshell, and has a modified choke. If you have a shotgun marked 2 3/4, do NOT fire a 3 inch magnum, even if it will chamber. The forcing cone will not have enough length for the shell to open, and it will cause unsafe high pressures. Every 200 I have seen (a limited number) WAS chambered for 3 inch Magnum shells.
Usually not, unless the shotgun is poorly maintained, too old, or poor quality to begin with.
i think the 50's at least
100-400 USD depending on condition.