Cat amongst the pigeons...
Accuracy comes from the paintballs and the gun's delivery of gas = consistency.
One of the best barrels I have used was a foot long piece of PVC pipe...
A tube's a tube... until you break paint in it... then there is a difference (because of if you can shoot it clean or not)... but until then 'pah'
Ohh controvertial huh?
Porting works to make the shot quieter, and to let rain into your barrel...
Barrel matching is very important... to stop the balls rolling out the end of your gun on a closed bolt gun, other than that 'pah'
Ever see pics of the All A's? how come they all shoot Diablo but still have large bore inserts in their gun's almost exclusively?
Same for Bob Long's Ironmen.
I used a large bore barrel for 6 years with my RT and shot all paint with it, dead on accurate with small or large paint.
I've always been a fan of the straight rifled J&J barrels, I'm trying to get a cocker one at the moment.