Originally Posted by ThunderCactus
In practice, the BB bounces quite a bit inside due to the hop rubber starting the BB off on the wall of the barrel and the magnus effect messes with the air current around the BB, but it ultimately becomes centered in the middle of the barrel.
One thing that's critical to understand, is that once a BB has become stabilized (centered) in a barrel, it can only ever become DE-stabilized from that point. So for example if a BB stabilizes itself after 9" of barrel, and you have a 20" barrel, you run the risk of actually LOSING accuracy!
Is it possible to find out how long it takes for the BB to stabilize without testing dozens of barrels? It seems like this would be extremely important to know before you buy a new barrel.