...but i remember vaguely in past that Marui and some of the more venerable airsoft manufacturers said that the bb does acutally touch the innards of the inner barrel. IIRC, near the exit where the Initial force of the compressed air is more dispursed and the bb loses some of the cushioning and results in a "bouncing effect"
Perhaps this may be speculation and i am sure everyone will contend. And I am sure to get flamed for that one.
Dont know about present times but just throwing it out there.
"May you fight with the strength of ten full grown men."