CO2The biggest challenge for playing in the cold weather comes from those that play with CO2. Carbon Dioxide propels paintballs by going from a liquid state (how it is stored within the CO2 tank) to a gaseous state within the breach of the gun. The change from liquid to gas is an endothermic reaction which means that it takes heat from the air to turn the liquid form into the gas form. When you are playing in the cold, two things happen simultaneously which negatively effect the paintball gun’s performance: slower expansion of the gas and liquid in the firing chamber. The slower expansion of the CO2 causes extreme variability in how fast paintball guns shoot - one shot may be 200fps and the next will be 300fps. Not only does this destroy accuracy, but it requires more CO2 to operate and often is insufficient to recock the bolt. When liquid CO2 gets into the firing chamber there can be extreme spikes in velocity which often lead to paintballs breaking in the chamber and blown-out o-rings.
A further issue here is that when you fire in the cold the whole gun will eventually freeze. It can get so cold that when you shoot a paintball gun you will see white flakes come out of the barrel which is dry ice (frozen CO2). When guns get extremely cold not only are they difficult to hold and continue to use but the metal and plastic pieces change size and the mechanical portion of the gun will often have issues.
This problem can be addressed by using compressed air. Compressed air does not have to go from liquid to gas and it does not require warm air temperature to operate which allows it to work properly at a much larger range of temperatures. Cold weather may still slightly decrease efficiency, but compressed air works very well in temperatures drop.
PaintballsPaintballs are designed to function properly at specific temperatures. Most paintballs are intended to be used in warmer temperatures, usually around 60 to 80 degrees Fahrenheit. When you use those paintballs in colder temperatures, one of two problems usually result: brittle paint or paint that will not break. Some paintballs will become extremely brittle when they get cold which leads to paintballs breaking in hoppers, within the firing chamber and when going down the barrel. Agitated hoppers, in particular, can cause significant problems as they can literally turn an entire hopper of paintballs into a soupy mess. Other paintballs, though, have the opposite problem where they become hard and will not break. You do not have the problem of paintballs chopping, but when paintballs do not break on contact the whole point of the game is defeated. I played once in the cold where some of the paintballs would not break even when fired directly at a tree from less than 10 feet away - needless to say we couldn’t play with that paint.
A solution to this issue is to use paintballs that are formulated for playing in the winter. They have slightly thicker shells and while they are unlikely to break in the gun, they still don’t break as easily as normal paintballs on contact.