Few tours ago I took up a c202 just to see how many I could shoot down with twin 50s, sure enough I landed 8 kills in one sortie. I took off and chased down a couple of carrier planes whose CV got sunk, then flew to the field to play around hoping someone would up, ended up with a heavy 38 that kept trying to up.
A decent aimer can score a few kills, maybe not as many as the 38 I can remember would not ditch his ords, I simply aimed for an engine.  Granted this is pot luck, but I do recall shooting down a P-47 with twin 50s from a Ki-84 with less then 50 rounds total. 
Most likely you won't score a kill on a snap shot on someone in a Ki-43, but then again if you want big guns go fly a Me-410, big guns won't matter when a Ki-43 sits on your tail and peppers you to death. 
Model Type   Kills   Percent
Bf 110G-2   1   12.500
F6F-5   1   12.500
P-38L   5   62.500
SeaFire   1   12.500
Late War Tour 142
Kills by Butcher in a
C.202 by player name
Player Name   Killed   Percent
Nightfal   5   62.500
Pappy08   1   12.500
Pepsi   1   12.500
THESWEDE   1   12.500
    8 Kills