I can easily shoot down a whole formation of b17s before my guns go dry and that just seems a little unrealistic.
You are right, it is unrealistic, but that is not the fault of the guns, or the planes.
Most planes are harder to down than their real counterparts (if we exclude shots to the wings)
Are you attacking B17s in BOX formation? no, right? maybe that is why you find easy... in real life they had to use very fast approaches to avoid getting shot by all those MGs. Result: they used more ammo to hit the target, it was not carefull aiming as YOU do, it was a go-through-them firing full speed -I don't wanna get hit- pass, and usually from any other angle than 6 o clock.
and yes, UP30 calibrated guns, but if you don't put yourself in the real situation, you will still think it is "too easy".
Guess what? those big Luftwaffe cannons were meant to do exactly what you complain about: shot down a 4-engines in a few shots (as long as you actually hitted, that is), the key is that they cared about their lifes while you do not
