1. The gun is fired with no roll (side to side tilt).
2. Your barrel is clean.
3. Your velocity is as close to 280fps as possible.
4. The paintballs you're using are as close to perfectly round as possible (use real good paint, I prefer Evil over here in the States).

Sounds to me like your friends Flatty is just fine.  Are you running HPA, or Co2??  If using Co2, this will cause variations in the FPS shot-to-shot,  and this will cause some deviation.

Make sure you get a regulator if running C02, or just make the switch to HPA.  Most HPA tanks are pretty consistent as far as velocity goes over the shot life of the tank.

High quality paint works best, because there is more consistency in the shape of the paintballs.  Use Marbs or Evils, those seem to be the best.

And yes, make sure you hold the marker straight up and down when firing, otherwise the shots will curve.

Have fun playing with it, and don't give up too early on the barrel.  She's picky, but treat her right, and you'll be rewarded!

jj

scott essery wrote: My mates just bought a second hand flatline barrel and we have just put it on his A-5 and shot 600 proballs through it.  Though they were going straight and flat (no dip) over the 60 foot firing range, there was a LOT of side to side deviation.  One shot the balls were 2 feet to the left, next 2 feet to the right, next spot on, next 6 inches to the right, next two 8 inches to the left etc. what could be going on? I have heard of guys setting up flatlines but dont know what they mean How do i set it up? The barrel seems ok.  i cant feel any gungy build up on the inside with my finger, there does seem to be a few 'lines' on the inside where it seems the white/grey rough surfac has been scoured away...but im not sure what im looking for. im not sure how to coorect this problem or waht is happeneing. Any help and id be really appreciative. we are both a bit dissapointed cos my mates been wanting a flatline for ages and ive got one on order too!

"Setting up" a Flatline is nothing more than making sure it is installed correctly...tightly bottomed in the adapter and rotationally oriented in the adapter so that flight is straight with no curve to the side.

If paint is curving first to one side then to the other that is not an indication of incorrect set up. It is an indication of either oversize paint (the Flatline likes small diameter paint) or low quality paint that is dimpled, out of round, or inconsistent in size from one ball to the next.

Marballizer is the standard "high quality" paint usually suggested for the Flatline. All Star is also good. And I have had good luck with Diablo Heat. Most, if not all, of the Diablo paints are small diameter.

Too large paint doesn't smoothly roll against the curve of the barrel. It scuffs against the sides and bottom of the bore so it exits with inconsistent spin.

The inside of the Flatline barrel is bead blasted so that it presents a high friction surface that will allow the ball to get traction so it rolls rather than slides. The inside has a frosty look...meaning it is smooth but not polished . Clean it with hot water and soap (Dawn dish detergent...paint balls leave residue after a few cases through the barrel). Flatlines go for several hundred thousand shots before wearing out (getting too smooth on the inside). If it needs to be refinished (new bead blast) send it back to Tippmann . They will make it good as new at no charge.