Ok,
The 18 inch will NOT out shoot the 12 inch. The distance is the same on any gun with any barrel that is shooting 30 fps. The only barrel that shoots farther is the tippman 98 flatline and the accuracy is so horrible with that barrel that it out does any advantages the barrel has. It makes it go farther by putting a backspin on the ball. Other than this all guns at 300fps shoot the same range. It's physics
As for the accuracy this has nothing to do with a longer barrel. This has to do only with paint to barrel match and the user. A longer barrel will NOT be more accurate, especially a boomstick. A boom stick is a 2 piece barrel and only the back part of the barrel will touch the ball, and all Boomstick backs are the same size so a different length will not matter.The best way to get an accuracy increase is to get a good paint to barrel match. They should be the same or as close as possible to the same diameter. Go to
www.paintballgear.com and go under the barrels to find bore sizes. You can also find paint sizes. Get a barrel that will match the paint that you normally use.
An 18 inch will only be a hindrance to your game. I would reccomend a Freak kit over the boomstick. If you don't have the money now then wait. With a Freak you can match the barrel to paint sizes using inserts. This will ensure accuracy if you ever have to use different paint or if you go to a field paint only place. Hope I helped.
