Abstract: A pneumatic paintball marker has, for example, a bolt assembly with a boost feature. The bolt assembly has multiple air supply chambers which apply force to move the bolt towards the firing position. Preferably, the air supply chambers push the bolt in series. The marker includes a handgrip frame that has a rear portion that flows into the base of the body. The material of the rear portion preferably is a rubber. The bolt assembly includes a set screw so as to prevent the bolt assembly from rotating within the body. A pin depth of the airport component is user adjustable.