you mean porting? rifling that tries to spin the paintball is the ultimate waste of time because A. if it isn't perfectly bore matched it'll have no effect at all and B. paintballs aren't made for spinning like bullets since they are a completely different shape.I started off with an a5 sold it after first walkon, moved to an invert mini - sold, now own a vanguard demon 2013 and an angel sb
also with the barrels - im pretty sure they dont do much to accuracy? same with barrel length - 14" is the best i do believe so anything more is just to help you point it in the right direction.
and rifling just reduces efficiency as theres more holes.
Just my 2 cents there