accuracy issues?

I have a custom 98 fitted with an rt and cyclone with a full metal interior and i use compressed air, and everytime i shoot with my teardrop(14inch)  my groupings about a foot and a half or so at about 50 feet. I find it slight inacurate ( the occasional ball off course is aceptable) but i was wondering if their was anything else than hte barell that affects accuracy i should look at.

Currently i have a rear velociy adjuster and iam not sure which setting would be best in order to have enought air to shoot the ball properly(velocity), and have my rt and cyclone work well. I find that when my velocity is to low my rt doesnt work... Is it broken?

My dads freak gives better accuracly but the second i shoot bursts(lets say 3 shot burst) the grouping is horrible. Is this normal?

I got the gun off my couzin and only get to play once in a while so i guess i;d call myself a newb...

Any barrels worth buying that would realy increase accuracly? What about the m-16 style ones, are they realy accurate? or is it jsut looks?

Thanks for the help

Frank

Thanks a lot guys. Iam using x ball bronze but their are a lot of small flat spots. The balls do role down so that would explain it, the accuracy is indeed better with the freak set.

Clear and usefull explinations. il take it out on the crono at the court, i just dont have anymoney to spend on buying one.

As for the three round burst would it be possible the next two shots that follow dont get the same amount of velocity? on my brothers rodeo with rocking trigger the pressure guage drops as you shoot faster. could this be an issue on my tippman? is it fixable?

Thanks a lot and sorry if this has been asked but i realy dont come around very often and when i do i only look at the 3 recent pages or so, depending if i have time.

Frank