I uncovered 3-inch .410 shells/guns from 1933 described on a cartridge collector site, but I'm having trouble finding reference to when a 3-inch 12 gauge first came along. I have an old single barrel 12 gauge 3 inch that I suspect is from the 1930's or before.
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.
Yes, you can use 2.75-inch shotgun shells in a 12-gauge shotgun that has a 3-inch chamber. The shotgun is designed to accommodate both shell lengths, so firing a 2.75-inch shell will not pose any issues. However, always ensure that the shotgun is in good working condition and that you are using the correct gauge ammunition.
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.
100-400 USD depending on condition.