I would recommend checking online forums, Youtube and doing a quick Google search and you should be able to find multiple people who have installed this on a Mossberg 500.
If your shotgun uses the same attachment pattern as the standard Mossberg 500, then it should work, but is not a guarantee.
If your shotgun uses the same attachment pattern as the standard Remington 870 or Mossberg 500, then it should work, but is not a guarantee.
It is compatible but you will need to check your local, state, and federal laws to be sure it is within legal limitations.
The stock is removable and you can use a mil-spec AR stock.
It has that capability but you will need to check with your local, state, and federal laws to be sure it is within legal limits.
No it will not fit as it is not an exact clone of the Remington 870.
The BlackHawk Knoxx Specops Gen 3 Shotgun Stocks pistol grip does not have a cap.
Unfortunately, Burris does not make a SpeedBead mount that is compatible with the Mossberg 500 due to the tang safety.
The BlackHawk Knoxx Specops Gen 3 Shotgun Stocks w/Recoil Suppression Technology will not work with SDA ART02. These BlackHawk Knoxx Specops Gen 3 Shotgun Stocks w/Recoil Suppression Technology models fit Remington 870 and Mossberg 500 models.