The lighter calibre AA isn't all that accurate. I've chased (and been chased) right along at hangar rooftop height and not get nailed.
On the flip side, I've seen a guy try to ack-drag me and turn away and get nailed: *hard*. So I usually just fly straight through it. I actually live longer

Barrel-rolls work really well.
Some days I can dive bomb and release at 2000' without a scratch, others, I get lit up hard before I even get below 8000' AGL.
Dunno how it works. Phase of the moon?