What is the best way to kill bombers?

[Laurwin]

Yes icefire seems to be right.

Another thing to think about is the following: because bombers are so big targets - especially American viermots (B-17), actual pilot instruction was to open fire at double the range compared to normal engagement ranges (compared to small size fighters).

This above guideline was from German fighter manual 1944. Reasoning was, that the Germans of course calculated how many hits with cannons and MGs it took to destroy a bomber (not just damage it, but destroy/ shoot down).

Part of the calculation seemed to be that closure speeds were too high in all types of attack. There's not enough time to pepper the bomber, if you only start to shoot at about 300m distance. Americans didn't build their bombers out of bamboo and paper like Japanese may have done, American warbirds had been purposely built to be tough in their construction and design, it seems.

Of course the mk108 was a different solution for the bomber problem - you only needed few hits to destroy a heavy bomber.

Such reasoning would correspond to 600m for me, to open fire at bomber.
The bullets will be out of convergence , by definition, but they can still damage the bomber tremendously.

Aiming point needs to be slightly higher, you need slightly more deflection as the firing distance doubles to 600m, and you need to walk down the fire slightly as you make a diving attack.

So, effectively you lower the gunsight slightly into the correct 300m deflection position, as you dive closer to the enemy shooting at the same time. To my mind, this works quite well, even with .50cal.

What effectively happens in this case is that bomber gets shredded with hundreds of MG-bullets... In a P-47 this kind of attack could eat up a good portion of your ammo stores!

Sure, you spend lot of ammo, even if you're hitting him, but you're much more likely to kill a twin engine bomber, shall we say, in only one attack pass.

The price that you pay in ammunition stores in aircraft, you remeed in exchange for one-kill-attack, and it takes less time in the engagement zone, (when you're vulnerable with your attention focused on shooting down the bomber)