the hammer and mag are mechanical components and are not capable of knowing anything. the valve on the mag is closed when the hammer resets, which only occurs when the slide cycles and resets the hammer. thats why dry fire uses less gas, the slide cycles right away instead of waiting for the BB to clear the barrel. the amount of gas used to propel the BB is: the volume of the barrel from hopup to mussel, multiplied by the pressure (psi or bar).
Originally Posted by voorhees -FWA-
but my point is, the same amount of gas is expelled out of the mag regardless of there being a BB or not... How does the hammer and the mag know there's a BB in there... don't care what happens to the gas after the striker valve is hit as you said, "dry fire on a gas gun uses less gas." That's what's not making any sense to me... you and Jeff gave me an explanation on what happens after the valve is hit by the hammer...
Meh, whatever... OP use less BB's and see what happens; instead of 40, try 20...
here's a brake down on how it all works.. or maybe a powerpoint presentation with pictures would be more helpful?
ok.. at the start with the gun ready to fire. mag inserted, hammer cocked.
you pull the trigger and release the hammer, hammer travels forward and strikes the valve striker (firing pin). the valve striker now pushes the valve in the mag open where the gas starts to flow.
(positive pressure valve system) BB is loaded and sits inside the hopup chamber. it applies physical pressure against the flute on the valve keeping it in the open position. once the gas makes its way up the gas port, it is directed forward towards the BB and hopup. the BB now starts to accelerate due to the gas pressure building up behind it, until it reaches the end of the barrel where it then proceeds to your target.
once the BB has exited the barrel, the pressure inside the barrel drops. since there is a pressure difference now between the barrel side and the expansion chamber side of the valve, the valve is sucked forward and seals the barrel. the moment the barrel is sealed, all the gas is now redirected into the expansion chamber. the slide starts to cycle and re-cocks the hammer, releasing the valve striker and thus releasing the valve in the mag, cutting off the gas supply.
(negative pressure valve system) mag in, BB loaded and hammer cocked.
trigger is pulled, same exact thing happens as explained above. the difference is how the valve inside the slide works. the valve is kept in the open position by a spring. once the BB leaves the barrel, once again the pressure difference between the barrel side and the expansion chamber side overcomes the force of the spring and seals the barrel, at which point the slide cycles and re-cocks the hammer and the valve in the mag.
if you understand that, then you can see how removing the BB from the barrel would reduce the amount of gas used for every cycle the weapon is fired. the volume of gas that would have been used to propel the BB is not used. this also makes the gun cycle sooner or faster as it has skipped the action of pushing the BB out the barrel before it cycles the slide.
i hope this clears it up for you, and if not, then you are either trolling or should stop explaining to others how you think something you have no idea works.