Yes. Probably hasn't been one made since 1920 unless they are still used in Europe.
Stevens and H&R made single shot 24's here until the late 30's. They are still made in Europe, and I believe you can get shell through Fiocchi.
Yes
Not a thing
Yes. The Mossberg 500A1 is a .12 gauge shotgun.
To determine exact value of a 1904 Marlin 12 gauge pump shotgun, you would actually have to take a number of factors into consideration. The main thing to consider would be the condition of the shotgun.
A bolt action shotgun in 12 gauge.
Yes, a 12 gauge shotgun is considered a firearm.
Any old shotgun stamped "44 Cal." or using the number 44 is chambered for the cartridge which eventually was modified into today's .410 gauge bore. They reportedly fire the .410 ok, but are not as good generally as the true .410 shotgun.
There is no such shotgun gauge.
What is the value oof a .410 gauge shotgun
Standard 16 gauge shotgun shells.
It is a shotgun with 20 gauges.
No, you can not shoot anything but 12 gauge shotgun shells through a 12 gauge shotgun. Never use any ammunition other than what the firearm was designed for.