What caliber is a paintball?

Answer 1

Very much so. Paintball guns come in .43 .50 and .68 caliber, none of which can be used in place of the other. .50 and .43 caliber has been shown many times to be inferior to the common .68 caliber however. The size/mass/volume/and ballistic coefficient of the .43/50 cal are not able to match the performance that the .68cal is able to produce currently.

Also within the .68 caliber range there are differently manufactured paintballs averaging about .685 but usually range +/- .015.

This paint bore, and its matching to the barrel bore is the most important factor in accuracy: If a ball is smaller than the insides of a barrel (barrel bore) the ball may bounce around inside the barrel as it travels. This will cause in-accuracy. However a ball that is bigger than the barrel bore may break inside the barrel from the friction. It is common belief that finding the proper fit between paint and barrel (paint to barrel match) makes for the best effect.

Answer 2

Paintballs ate .68 caliber. Some pistols or specialty guns are .50 or .43 caliber, but they are very uncommon.