F4U1C needs to 4.3/4.0

The only difference between F4U1C and F4U1D is just the weapon; is 4*20mm really worth 1.7 BR? F4U1C’s performance is probably the worst one at 4,7, even most 3.7 aircraft could easily defeat it. Does Gaijin really believe the firepower should be the first thing to consider the balance?