Here is Blaze's post from the STF:
I think he is wrong saying that the pc size doesn't matter, but someone here may know the exact details. [aka Doom]Oh and one more thing, I am totally sick of Dux and Nibor (especially Dux) saying that the 21K is great because it has a lot of shots. IT PUTS OUT THE SAME FRIGGIN 68 OZ OF WATER IN THE RESERVE ITS JUST THAT YOU'RE PUMPING LESS FOR EACH SHOT! SHUT UP!
And while I'm on that subject, I would like to point out that PC size really doesn't matter. The reserve size does. Small PC=more shots, less shot time, less pumps. Large PC=less shots, more shot time, more pumps. They both have their advantages and disadvantages. I would say they are about equal.
<EDIT> and I know that you are still using the same amount of water, the issue is the way the water is used.