Originally Posted by nenkitsune
Because whenever you increase flow, you increase the velocity of the paintball. It'll get to the point, that even with the stiffest valve spring, and weakest striker spring, the velocity will be too high. In fact, you may run into the issue where you need a lighter striker spring to bring the velocity below 300fps, but if the spring were to become any lighter, the gun would fail to recock because it wouldn't be able to open the valve enough to get enough blowback gas (in theory i should say, however, this could be remedied by griding portions of the valve pin to direct more air to the striker)
you are going to need some sort of regulator to drop the pressure if you intend to do any substantial modifications to the air flow.
I think he said he plans to slot mod it, in that case he would be fine doing whatever. It pump guns, higher flow= lower spring tension= easier cocking.