OK butcher, so the M4(76) will never need more than 1 shot to kill anything in the game at under 1000yds or so, regardless of circumstances, glad to know the Tiger II, Panther, and Tiger are grossly over-perked, and I'll be sure not to drive them when I get back

.
Tanks that can/sometimes DO require more than shot to kill:
Tiger II
Tiger I
Panther
M4(76)
T-34/85
Panzer IV
Tanks that potentially could (but I have yet to see in combat) need more than 1 shot to kill:
T-34/76
M4(75)
M4's if they're covering the bottom of their hull will almost be guranteed to need more than 1 shot to kill.
Tiger II's will ALWAYS need more than 1 shot to kill, since the M4 can't kill them from the front.
Tiger I will almost always need more than 1 shot to kill it.
Panther will usually need more than 1 shot to kill it.
And the Panzer IV will sometimes need more than 1 shot to kill it if you miss the turret, usually when hes angled.
The Firefly is basicly guaranteed to kill any tank but the Tiger II, Panther, and Tiger I in a single penetrating shot, regardless of hit location. And it will often one-shot Panthers and sometimes the Tiger I.
And about the damage, the current system seems to assign a damage value for each shell (infact, I'm almost sure of it, since the assign damage values to bullets and cannon shells). Firefly seems to have a higher damage value (based on its rarely needing multiple shots to kill the most common tanks at close-med range).
As for the rest of your post, its completly irrelevent to everything I was talking about. It doesn't have ANYTHING to do with the advantages you gain by driving a firefly. It just talks about the weaknesses of ALL tanks compared to the M18 and airsupport.