Here is a suggestion. Fly cannon equipped planes. You stand a much greater chance of not getting a kill stolen when firing 20mm vs 50's.
Myself, I typically fly planes with 6-50's and yes I do get kills 'stolen'. Sometimes I 'steal' a kill. I attribute getting kills stolen as much to my SA as the other player. Horde flying is when I get kills stolen or have an opportunity to steal a kill.
The current damage model is about how many hits you put into the plane. Sometimes you can put 50 rounds into a plane and not damage that planes ability to fly. Bombers are a good example. One cannon round in the right place and the guy who just put 50 bullet holes gets the kill.
That's the way the game is played.
Regards,
Malta
p.s. I don't rely on six calls in the MA either. 90% are too late due to lag and if I don't see the plane, a six call normally doesn't help. About 5% of the six calls I get help. The other 5% are nuisance calls that require a squelch. Not to discourage the practice, and I still try to give them out, but that's the way the game works. It's a bit eerie, but after a while you know when someone is on your six. The best use of six calls imo is when the (typically) FW190 is screaming in at 400ias trying to cherry pick someone on a climb out. I like giving six calls to spoil that shot!