Actually, plazus, a number of folks are commenting on something "feeling off" with the gunnery since the latest patch. Considering that all the planes suddenly became 20-30mph faster, perhaps EVERYthing became faster?
Perhaps the bullets, the acceleration, every aspect of physics became faster?
When they fixed the top speeds of the planes, maybe they left something else in place that still monkeys with the bullets' trajectory or physics?
I dunno if that's the case, but I've read a few other folks complaining of this since the last patch, as well.