Are tail-gunners bullet-proof?

[EJGr.Ost_Caspar]

Originally Posted by Lagarto

Caspar, my original post in this thread was not about wanting more blood but more realistic rear-gunners' vulnerability to gunfire

Well... they are not invulnerable. Did you go for steady testing before requesting a change or is it because of impressions/feelings only?
I don't say, all is correct. Maybe there are really wrong values in or at least irregularities. But then its no general problem, rather one regarding single plane types.
The gunners are in many cases somewhat protected by plane parts (to more or less degree), which can reduce the calculated projectile energy or divert them.
Also the gunners can get wounded - not every hit is lethal - and be only reduced in firing abilities/accuracy (since 4.10). They even stop firing, when they are heavily wounded, but are not dead.