After reading Green Hearts - First in Combat with the Dora 9, i really come to the conclusion that the dmg of the 0.5 must be reduced.
Nowhere in the book (which refers to the time sept 1944-end of WW2), is mentioned that the 0.5 was a very deadly gun.
But there are many reports of D9 getting shoot up and still returning home (btw most often with intact engine and radiator

), cause the 0.5 cal only used massive bullets instead of explosive shells like a cannon.
i.e. a D9 returned home with 25 0.5 cals in it, in one prob blade there were 3 wholes, 2 bullest were stopped by pilots armour, and there were a couple of bullets that passed through wing etc.
in AH we have no bullet path modeled that recognizes if a bullet hits a vital part, instead we have accumulated dmg, which means the 0.5 cal in AH is much more powerful than it should, i guess the power should be reduced by about 10-20%, this may also account for all other guns with solid bullets like the MG131, the 0.303 cal, the 7,9mm MG17 and or the 7,7mm mg