Yes, reballs were made to be shot out of paintball guns.
You can buy rubber paintballs, they are called Reballs, and any paintball gun can shoot them. The police and militairy also have several specialized or modified guns to shoot them at higher FPS.
One can find discounted paintball accessories from Just Paintball, Paintballing, Discount Paintball, Zephyr Paintball, Outpost Paintball, Paintball UK and Armed Paintball stores.
Popular paintball stores in the US offering discounted paintball equipment include Paintball Discounters, Paintball Online, Discount Paintball, and Zephyr Paintball. Inexpensive paintball equipment can be found secondhand on websites such as Amazon and eBay.
Anything that is designed to be loaded into a paintball marker that matches the bore size of the marker (can be from .50 to .68 caliber, and typically would be paintballs filled with water, other liquids safe for use in paintballs, or "reballs", paintball-sized rubber balls used for practice and or training). Use of any other spherical objects are not intended and may damage the mechanical components and may render it unsafe to operate.
The purpose of a paintball gun is to fire paintball pellets, to mark opponents in the game of paintball.
Most likely a bad battery. Change it for a brand new one (not rechargeable). If that does not fix it take it apart and clean it fully, make sure to check ALL of your orings. If the problem continues, take it to a pro shop, it probably wont cost more then $20 for whatever parts you need.
A paintball marker is a paintball gun. It is just called a marker instead of a gun.
Paintball grenade launchers can be found online at Total Paintball Gear, Paintball Grenade, and Total Paintball Gear. They can also be found in sporting goods stores.
Yes
paintball fields or on their property.
No. There is no cruise line that has paintball fields.