Originally Posted by Crunchmeister
That seems a bit of a large gap. I tested my pistols using both .20 and .25. The one I remember best was my M9 that fires between 310 and 320 ,with, 2, and I was getting 290-ish with .25s, hence my estimate about the .25s about. I could be mistaken though. I'll check it out again when I have time to confirm.
Gas guns are WAY different when it comes to FPS differences between weights. They aren't affected as much. For example, my P229 fires 270 on .2's, and 260-ish on .28's. In an AEG, the system is steady, there is always the same amount of air pushing the BB. In a gas pistol, with heavier weights the BB in in the barrel for a longer time, allowing for more gas expansion and more energy transferred to the BB. Hence why I only shoot 10 FPS difference between .2's and .28's on my 229. Make sense?