Above all else, killing bombers requires patience. You can work on your interception, angles, speed and gunnery but without patience, you will only find yourself on their 6, and dead.
If I have nothing else, I have patience. 46 bomber kills this month with zero deaths, or bails, or ditches. I call out bombers when I see them and I do share. More than half the time I'm getting the kill after the other fighters have flown up their 6, wounded the buff and the died before the buff goes down. We got all day, he can't run away, what's your rush?
This post is not about my numbers, it's about your numbers. I'm not a great stick but I can shoot down buffs without damage because I am patient. It is always my goal to kill all 3 without 1 ping on myself which is not impossible to do. Then I've got an undamaged plane and can re-arm to hunt a few more.
Bottom line, I'd like the buff pilots to have more of a chance of surviving. How we do that, I'm sorry I have no idea.