What does the bore size of a barrel mean, and how is calibre measured?
The term bore size and calibre or caliber are interchangeable words. Calibre is the interior diameter of a tube, or in this case barrel. A barrels calibre is measured in hundredths of an inch. For example a 50 calibre rifle, often denoted by .50 calibre, is fifty one hundredths of an inch, or half an inch.
Paintballs tend to be a larger .691 calibre to a smaller .682 calibre. The calibre of the paintball will not effect its performance, however the match between the calibre of your barrel to the calibre of the paintball will effect both performance and efficiency of the marker and the accuracy of the paintballs.
Having a barrel calibre larger then the calibre of the paintball allows for air or evaporated c02 to move around the paintball instead of getting directly behind it. This means it requires more propellant to get a paintball to reach the desired velocity as it leaves your barrel.
Having a barrel calibre smaller then the calibre of the paintball is potentially much worse. Imagine trying to push an egg through a garden hose, yeah you get the idea.
Ideally having a barrel kit, with multiple choices for which calibre to use, is the best solution. Most kits come with a bore sizer, so you can check your paint before you play, and choose your barrel back or insert depending on whats needed.
Here is an old paintball bore / calibre size chart. Keep in mind the calibre of a paintball might change from batch to batch, and this chart shouldn’t be relied upon.
Tags: barrel, bore size, caliber, calibre, paintballs
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