Can Paintball Guns Shoot Marbles?

Man in fatigues playing paintball, aiming at target in woods
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Paintball guns can shoot marbles, though they are not designed to do so and can potentially be very dangerous. See how paintball guns work, what must occur for marbles to be shot, and also why you shouldn’t do this.

How Paintball Guns Work

Paintball guns are pneumatically powered (air powered) devices that allow compressed gas to expand behind a paintball. This propels the paintball down the barrel and out of the gun. Four factors affect how fast the paintball leaves the barrel: the speed that the gas expands, the volume of gas expanding, the weight of the paintball, and the fit of the paintball in the barrel.

Paintball guns use carbon dioxide (CO2) or compressed air and both expand at the same rate. The amount of gas released is controlled by a regulator in compressed air guns and the time the valve is open in CO2 guns. Generally, the larger the volume of air, the higher the velocity of the paintball.

Another variable is the weight of the projectile. Heavier projectiles require more force to move and if the pressure is equal, they leave the paintball barrel at a slower speed. To shoot heavier projectiles you must increase the pressure behind them by turning up the regulator or increasing the spring pressure.

The last variable is the fit of the projectile in the barrel. The expanding gas must be mostly trapped behind a projectile so it pushes the projectile down the barrel. Paintballs deform a bit when the air pushes them, which helps create a snug fit even if each ball isn't perfect. Excessive deformation of the paintball will hurt accuracy, but the ball will leave the barrel at the same speed as a paintball with a good initial size match.

Shooting Marbles

Marbles can be shot by paintball guns. The key is that you have enough air behind the marble to push it out the barrel. The marble must the perfect size so it just barely fits into the barrel. It won't deform like a paintball, so it must be the right size, .68-caliber. If it's more than slightly too small, too much air escapes around it and it won't be propelled down the barrel or it will only be propelled slowly. It's slightly too large, it either won't fit into the barrel at all or it may get stuck in the barrel.

If you want to get any velocity from the marble, you may have to increase the pressure of your gun as marbles are heavier than paintballs. You need more gas to get it moving and to make up for any gas leaking around the sides of the marble.

Why You Shouldn’t Shoot Marbles

The primary reason you shouldn’t shoot a marble is that it is dangerous. A paintball is designed to break apart and cause minimal injury on contact. Marbles, on the other hand, are solid like a bullet and not designed to break. A marble shot from a paintball gun could cause severe injury and could potentially break through a paintball mask and blind someone. For this reason, you should never shoot a marble at another person, whether or not they are wearing protective equipment. When a marble is shot the paintball gun is now a weapon and the same safety steps used with firearms need to be followed.

A second reason is that paintball guns are not designed to shoot marbles and they may damage your gun. The hardness and weight of marbles may damage the barrel and the bolt. The excessive pressure needed to fire it will sometimes cause other damage such as blown o-rings and overstretched springs.

The last reason is that shooting marbles is not that cool. You could shoot a BB or pellet gun instead. The marble shot through a paintball gun is slower and less accurate. It’s a hassle to find marbles that fit into your gun and they cost a lot more than paintballs. The best thing to do, then, is to use a paintball gun for what it was intended to do: to shoot paintballs.