I haven't bothered to read all these pages but on two issues, here's my 2p;
Lag - IMHO definitely occurs. I have sometimes been hit by a 109 making a near head-on pass when his line of flight moved from 11 o'clock to my 1 o'clock to pass down my right hand side and at no time within normal guns range was he pointing at me unless he shot very early from 1000+ metres when he was last pointing at me. It seemed he could not have hit me from normal range at his angle. But.... bang! Dead. I accept that no Tracer can add to the impression of imposssible shots but I'm happy (happy?!) that when it happens, its probably lag.
PKs in general. Sudden unexplained PKs (no tracer) perhaps due to mine shells exploding in a cluster around the cockpit. No armour to the sides. Loud impacts/explosions (not like the sound of 7.62mm hitting the airframe), instant black screen. Or simply a 20mm in the right place.
I doubt very much that its hacking.
I just wish the damn 109 pilots would oblige with a few PK deaths from my 0.303" AP!
No wonder the RAF pilots began asking for heavier armament.