Then you need one of these.If you made it the same weight as a .68 it would be superior in terms of accuracy, distance etc at the same FPS, you could make it even smaller than .50, make it out of lead to make it weigh the same as a .68, make it more of a streamline shape to makeit even more stable in flight - it'd cut down on the number of wipers too.
.50" calibre has been around a long time in the 'toy' paintball market.The new Splatmasters use 50 cal, I believe.
The idea is that the combination of a small ball and a cheap gun will bring more entry-level customers into the game.
(Less pain, fewer welts, cheaper, etc.)