Paintball gun barrels vary in size, color and design. In general, paintball gun barrels are twelve, fourteen, sixteen, eighteen, and twenty inches. Some people also make use of custom made barrels of about 48 inches. There are also barrels that are less than 8 inches but the accuracy rate of such barrels are very poor. The ideal gun barrel should be between 8 and 14 inches.

As the length of the barrel increases, the gas used also increases. A considerable amount of gas is used by barrels which are more than 14 inches. During warm seasons, short barrel guns are better. A longer barrel is ideal during cold seasons. The advantages of longer paintball gun barrels over shorter barrels are that they make less noise. This is mainly because of the porting that long barrels have. The term port refers to the holes that long paintball gun barrels have on the sides. Some people choose barrels which are ported to avoid sound. As the number of port increases the sound made by the paintball gun reduces considerably. But it is found that ported barrels use more gas to reach the desired velocity.

A vast majority of paintball markers use threaded barrels. Angel, Shocker, Tippman, and Spyder are among the common threads to be found. The inner diameter of the barrel is called bore. Nowadays, paintball gun barrels made of aluminum, stainless steel, ceramic, and brass are available for purchase.

One piece, two piece, and three piece barrels are some of the popular types of barrel. One piece barrels are made from a single material. The material used in this type of barrel is aluminum. Two piece barrels are machined from two different materials. Usually, it contains a front and back. Instead of multiple backs, three piece barrel features only a single back. The other types of barrel commonly found are flatline barrel and apex barrel.

Paintball gun barrels made of aluminum are lightweight and not expensive. Stainless steel barrel are long lasting and are scratch free. Barrels made of ceramic features low friction. Due to many disadvantages, brass barrels are not common nowadays.