Yes, Dick's Sporting Goods or Gander Mountain carries them. You can also find them at gun shows.
Yes try hushpower .410 12 & 20G
No.
@ the turn of the century
Yes they did make them, around 1930. I own two Iver Johnson SS shotguns with raised ribs, a 410 & a 12ga.
They started making .410s about as soon as the .410 shell was created- around 1900- and still continue.
Yes
i DID
the Winchester 9410
Dozens of makers have made 410 shotguns over the last 100 or so years. Winchester, Remington, Ithaca, Purdey, H&H are a few.
100-300 or so
Yes. Was looking at a new Remington 870 pump .410 shotgun today, in fact.
They are the same. Mossberg 500 series includes all shotguns. 500A is 12gauge. 500E is 410.