Bomber Gunners are way too Uber in AH. Bombers need to be escorted...ask any 8th AF vet lol. You could write a book on ballistics of Air to Air gunnery so this is not an end all...just brushing the surface. Please bear with and read.
Lets examine the Air to Air gunnery problem. I am a career soldier in combat arms in the US Army. Its is difficult to hit a fixed target at a known distance with a fixed gun. Many factors influence the ballistic path of a bullet. Variations in tempature, humidity, bullet weight, powder amount, ignition speed of the propellant etc... not to mention the shooters skill combine to make fixed gun/fixed target shooting difficult. Now add in just the environmental factors in Air to Air gunnery and its a miracle that with fixed guns mounted on a fighter you can hit anything. Galland said "You just get the feel for the right amount of lead". That's because the ballistic influence's are so great that each shot is different. That's why most fighter pilots waited til the "whole windshield was black with enemy" before firing.
Wind velocity greatly influence's your ballistics. A slight breeze can mean holding a .50 cal bullet several meters off target to compensate at 1200 meters. Now consider your plane traveling at several hundred miles an hour. As soon as that bullet leaves the barrel the relative wind begins to influence it. Its called Aerodynamic Drag and the size, weight, and shape of the projectile determine its exact effect. That is why most shooting is done from 6 or 12 o'clock. This is why a stern attack on a bomber is suicide. The relative wind pushes the bomber gunners bullet toward the attacking fighter but slows the fighter's bullet down degrading effective range. If there is any deflection angle then the relative wind blows the bullet off course related to its value. The greater the deflection angle the greater the influence. That's why you didn't attack bombers from the side..just about impossible to hit.
Gravity also influence the round and the firing platform. Gun barrels flex m8's. The slight force of a rifleman gripping his rifle will move the point of impact. That's why "floating" barrels are put on rifles. In a fixed wing mounted gun any G's pulled by the plane will bend the barrel further complicating the ballistic problem. Engineer's term this "trajectory jump". Basically it means that the Gun-Bore line and the point of impact can be radically different.
Now consider the flexible mounted gun of a bomber gunner. The turret is powered but the guns are flexible. As the gunner swings his 60-100 lbs of Machinegun/ammo (depending on whether he is firing one or two guns) on to gun/target line he will greatly hampered by the inertia of his own weapon system. Just the push of the relative wind on his barrels will make alignment with target difficult. Any G's pulled by the bomber would make the gunners job impossible. A 60 lb gun would be 120lb at 2g's. Finally the recoil of his own weapon system in a flexible mount would send his bullets all over the sky. During WWII the US .50 cal outranged the German fighters guns. German fighter pilots lining up for a shot on a bombers would see tracers buzzing all around them making any attack unnerving. The fire from the bomber gunners was extremely inaccurate though due to the overwhelming ballistic problem faced by the gunner. During the Schweinfurt raid on 17 August 1943 B-17 gunners claimed more German fighters destroyed than were even present at the battle. The 8th Air Force allowed most of the claims to stand for morale purposes. The reality is that in JG 26 (approximately 118 aircraft that made contact with the bomber stream and attacked) only 5 pilots were hit by B-17 gunners. 1 was KIA and 3 WIA and 1 pilot had to bail out but was unhurt. The 3 WIA made it back to base.
BOTTOM LINE- Unescorted Bombers should be fighter fodder.
Ketten
Sources:
1. "Fighter Combat: Tactics and Maneuvering" by Robert L. Shaw - Excellent book written by a 20 year fighter pilot and engineer. Required reading for US Fighter Pilots
2. "JG26 War Diaries: Vol II 1943-1945" by Don Caldwell - Day by Day chronicle of one Luftwaffe fighter wing from the beginning of WWII to the end. Transcribed from the units official War Diary it includes allied/axis ground controller input, victory/casualty list, and Allied/Axis personal accounts. One of the best books I've found on the Air War in Europe..even has gun camera stills ID'ing pilot and plane being destroyed. Rather pricey though, the set will run 100 bucks.