Team Wolfpack: Paintball Size Bore Chart
Sorry this is a bit outdated.
Paintball brands and models vary in bore size. The .680 caliber designated by the industry is its target. Any serious paintball player wants a good paintball to barrel bore match. Keep in mind, for the most part, you get what you pay for when it comes to paint. Unfortunately, most paintball fields require you to use their paintballs and they overcharge for cheap paint. The list below is an average size of these paintballs, many paintballs vary size within a single bag. Of course, oval or dimpled paint is a problem in its self.
Posted by Redwood a long ass time ago(2004?)