I do not have any first hand scientifically gathered data regarding the effectiveness of porting on accuracy.
The theory that I have heard is that by releasing some of the air inside the barrel, in front of the ball, as it races down the barrel toward the muzzle, reduces the amount of turbulent air at the muzzle when the ball hits the air.
On the other hand, I covered my porting with stickers and electrical tape at plenty of rainy tournaments without obvious deleterious effects on accuracy. This anecdotal data doesn't mean much, because it wasn't measured in any way and there were other variables involved (like rain).
It seems like both Broz and ADJ are basing their statements on the wisdom of other people, both of whom are respected designers.
I suggest that if anyone cares enough, that bench mounting a gun and shooting at a blank target at say 15, 30, and 45 meters and measuring the spread with and without the porting blocked in an airtight manner would be illuminating. Otherwise it is just dumb to argue, since it is conjecture without evidence about factual matters. Arguing about facts is dumb.
Challenging someone's advice to new players is quite valid and useful if the advice is in question. There is so much hype in this sport that believing anything that isn't tested independently is silly, no matter how well intended or who agrees.
I was gonna sticky this if it had real facts, but so far it seems like opinions all around.
