In excess of 50 m
The shot will travel a couple of hundred yards, easily.
Are you interested in knowing how far a 12 gauge slug will travel, or are you looking for the distance various loads of shot will travel?
I don't understand the question. Were you shot in the back with a .22 and wonder how far it could have gone?
Have it checked out by a gunsmith before you try it.
A 410 bolt action with a 3-shot clip is value at $80.00
#6 shot
about 36km
Depends on which gun. A simple single shot .410 may cost AROUND $150. A collectable Winchester pump, maybe $1,000. A Purdey double .410, about $3,000.
Yes Iver Johnson did make 410 shot guns, I own 2 break open 410 shot guns both made by Iver Johnson.
Muzzle loader or centerfire?
Depending on the load, a couple of hundred meters is possible