The bore of a barrel does
*absolutely nothing* to affect range or accuracy.
tighter barrels may foul quicker, leading to accuracy loss due to fouling, but as long as you keep your barrel clean you won't have an issue.
And that article you read was completely bogus. Case and point: they actually recommend PDI raven (PDI's competition for madbull aluminum and angel custom, IE: cheap garbage to fight cheap garbage), angel custom, and miracle barrels, all of which are crap. And they recommend the PDI over the prometheus for long range, which means they didn't do any research at all, because the prometheus barrel is actually the better of the two.
Prometheus 6.03 and PDI 6.05 are the best, period.
Best economical barrel would be the madbull 6.03 stainless.
And the whole idea of a "CQB barrel" is completely ridiculous. If a barrel is more accurate at short range than another barrel, then it's going to be more accurate at long range, making the idea moot. And if the purpose is to have a barrel that's just "good enough" for CQB, then just keep your stock barrel instead of spending $40 on a spitball gun, in which case you'd be wasting money on a new barrel that offers no advantage over a stock barrel, and the perfect barrel is just an extra $10-$20 anyway.
Give this a read, as it's based on physics, not unverified personal opinion.
http://www.airsoftcanada.com/showthread.php?t=166583