Lapco Big Shot for X7

The Big Shot is a larger bore barrel (.69 I think) and as such is very tolerant of various sized paint.  It is (along with the J&J Ceramic) recommended a lot on this forum.  There is really not a significant difference in performance between 12" and 14" barrels of the same type.

I have the 12" Bigshot on my 98 and I think it's superb!

I copied this info from Paintball Times article "Barrel Myths":

"Length is a common misconception. People think that a longer barrel will be more accurate, that is not correct. Longer barrels help on firearms because the longer the barrel the higher the velocity (FPS) the bullet travels. In paintball no matter what the barrel length we adjust the velocity to 300 FPS (feet per second). For a good paintball barrel length you just need enough length for the gas to expand and get the ball going 300 fps. Ideal length is 8-12 inches. Anything over around 12 inches will make a drop in your FPS (compared to a 8-12 inch barrel) and require you to turn your velocity up (requiring more air). A longer barrel also increases the chances of a ball breaking in the barrel. A barrel shorter than around 8 inches will require more gas also because by the time the ball leaves the barrel the gas wont have had enough time to expand behind it, this requires you to turn up your velocity (using more air). It also increases the chances of breaking a ball because you have to have more air hitting the ball at once to make up for the lack of time for the gas to expand in the barrel so the initial harder "smack" could break balls. What else besides length matters?"

Read the rest here: http://www.paintballtimes.com/Article.asp?ID=305