Tippmann barrel

I agree with Mc Wolf who said:

"effective length for a barrel is 14" after that it starts to require more air to push the paintball through the barrel at the same speed"

Although the problem is your C02 tank or compressed air tank only let's out so much C02 or Compressed air per shot.  So you you wont be losing more C02 or compressed air with a longer barrel but your ball wont go as far.

Here's how it works: in the first 8 inches of the shot the ball flyes about 50 000 feet per second (which is incredibly fast) but after those 8 inches and especially once the ball leaves the barrel it drops to about 300 fps.  So if the barrel is longer than about 14 inches than the ball will lose velocity because the ball will be touching the inside of the barrel - (friction makes things slow down of course). 

To some up the more time the ball has to bounce around inside the barrel the less accurate it will be and the slower it will be.

It is a so have a longer barrel doesn't make more accurate or make it go farther which is what some people think.

I think you should go with something like a Lapco Bigshot, or a J & J Ceramic but only 12 or 14 inches.  Or even better go with a flatline barrel just make sure it's set up properly.