Originally Posted by Dr. PhunkyPants
You should definitely keep the pump handle held forward when firing. On any sniper style pump (not just CCM--all cockers), the bolt has a hole in the bottom of it which when positioned fully forward aligns with the interior air passage from the valve in the lower tube.
If you attempt to fire while the bolt is not correctly aligned to the forward position, the hammer hits the valve, the valve opens, but due to restricted airflow not all the air goes through the bolt to hit the ball. The result is low or NO velocity on the ball. In fact, the bolt pin will keep the hammer from hitting the valve somewhat, so you may not even cycle.
A more common problem is shooting without a hand on the pump grip. If you do this, the gun will shoot but you will lose velocity. The reason is that (1) some of the kinetic energy from the air moving through the bolt is diverted to pushing the bolt rearward and (2) as the bolt moves rearward, it cuts off airflow. Less air and energy hits the ball--thus lower velocity. It also happens to be quieter.
Okay thank you for your insight. I really appreciate all the info! I'm more of a stealth player so that's why I want to be as quiet as possible when shooting.