No, do not expose your paintball gun to water.
Paintball gear is what keeps you safe in paintball. The mask is the only truly crucial piece you need to play paintball (meaning you can walk onto a field without a gun, or tank or paint).
Yes you can but you will have to take it to a Paintball veils or wholesaler to make sure it is safe and legal to use while playing
It depends on the amount of FPS (feet per second) the gun is firing at. But a good paintball gun will leave a good scar at a point blank distance. Any further than that and it will leave a welt.
The purpose of a paintball gun is to fire paintball pellets, to mark opponents in the game of paintball.
A paintball marker is a paintball gun. It is just called a marker instead of a gun.
typically yes, but its a good idea to call the police jurisdiction in the area as ask them first, and make sure that at any point on your field a paintball can not be fired and reach a public area where anyone outside your game could be hit or their property. if near houses the police like you to go to the closest houses and ask the neighbors, this is also a nice to do so they know what all the noise is
not often but in rare cases a luky shot might
It depends on what you mean by "sell". If you mean put it on Ebay for trade, or on PBnation then no. you have every right to do so. If however, you mean to open a shop and sell goods then yes.
No. The state of Ohio did not invent the paintball gun.