How They Work
Most semi-automatic mechanical paintball guns are blowback guns. These fire when the pulled trigger releases a bolt which is propelled forward by a spring and pushes the paintball into the barrel. Once the ball is in the barrel, the bolt strikes a pin, opening the valve, allowing air to go down the barrel. The bolt is forced back to its original position by the force of the air expanding (the name "blowback" comes from the fact that air blows the bolt back into position).
There are many different types of mechanical guns that come in many different price ranges. They range from basic plastic pump
s to precision-milled guns that cost over a thousand dollars. Here I will discuss the most common and most readily available blowback mechanical guns.
Mechanical markers are typically quite reliable and need little in terms of regular maintenance. They should be cleaned and oiled after every few uses (ideally after every use) and o-rings should be replaced as needed. They are usually very easy to disassemble, so if one does develop a problem, parts are inexpensive and a mechanically inclined person can often fix it without too much trouble.