no when your shooting at something you will never tell
It depends on the comparative charges of the ammunition. A rifle can have more recoil than a shotgun.
Yes, it is larger, the smaller the gauge the larger the bore i.e. 3 gauge is larger in diameter than a 8 gauge or a 12 gauge.
It would depend on the load you were using, but generally no, a 20 ga would "kick" more
A little bit more than a 17 gauge but less than 19 guage.
Yes. Some shot types are more lethal than others, but any shotgun can be lethal.
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.
Unlikely more than 125 or so
Seldom more than 100 USD in excellent condition.
No more than 100 USD.
No more than 100 USD, if that.
Highly unlikely you will find any. Getting them made will probably cost more than the shotgun is worth.
the 10 is alot stronger and has more ranger but 12 is better for hunting.unless your hunting very big game