Effective range, certainly. If I see anyone claiming that, I'll join in the kicking. I'd agree, in fact I'd recommend, that any tinkering with an airsoft toy start outside the gearbox: hop unit, rubber and barrel, battery connector.
However, all that any airsoft toy does to the BB is puff, spin and point. The last two give you accuracy, the ability to lift heavier BBs, and a flat trajectory to the end of your range, which is what you want most of the time. Ultimately though, if we're talking the maximum possible range, then producing the maximum permissible puff is also necessary.