It's the Mossberg 500 12 gauge.Mine is 20 gauge. Not as much kick on the wrist and still kicks home invasion butt. I recommend putting the pistol grip on with a shortened stock for recoil help and ease in home/hallway movement myself.
3" Magnums, #2 Buckshot for me. (I'm a cheapskate so no "big brand" ammo) and slugs for when you need that extra something.
You can get #1 Buckshot for yours.
I finally broke down and purchased my first gun for home protection.
While I commend you for taking steps to protect your family and property am I to understand that this is your first gun ever or do you own something else as well?