because inside of your paintball gun is a rubber or plastic peice called the ball detents that holds the ball in place until shot. It could be that the detents are missing or damaged.
Paintball is a game where washable paint capsules (called paintballs) are shot from markers (guns) in order to mark and eliminate the opposing team. These gelatin capsules are regulated to shoot just...
It all depends on where you live. If you have like a few acres of woods in your backyard you can break trees and set up bunkers there. If you don't there are usually at least one paintball place...