You can't increase the range on a marker under normal circumstances.
A paintball weighs so much, you use so much air, the ball has a certain ballistic coefficient, so it goes a certain distance.
If you marker is shooting consistently and your paint is consistent, you should be ok.
A 16 inch barrel will not make it go any further, in fact it could reduce the distance and or accuracy. You only need 8 inches of barrel to accelerate a paintball up to speed. Optimum length is 12 to 14 inches.
To increase range, you have to impart back spin on the ball.
You could use an Apex barrel (not look good on Ego8) or you could carefully cut a channel into the inside of the barrel at the very bottom.
This MIGHT, impart back spin, as air will rush past the ball faster at that point.
If you paint to barrel match is not right (barrel too big), then the ball will sit in the barrel, with a gap above it. This will impart top spin on the ball and make it drop off very quickly.
Standard back size is .693. If you are using very small paint, that will be your problem.
