i agree with, Cav and NoName ,
most of the buffs are bombing at 10-15k, and K-4 has great, maybe the best climbing speed, also fast at that alt, you can make multiple passes at high speed, safe attack them from above, ignites the fuel tanks, specialy B24s, vertical dive and fire cannon only , soo you know when hit with the 30mm, not with useles mgs, cuz the trajectory is diferent, same like in IL2 killing gvs,
if are close to your base, the bomber pilot must be in F6 mode, doesn't have time for gunning, can take risk to park behind and blast them
f4U-4 is also great interceptor, i think outclimbs the K-4 from 14-to 20k ,
P47N, and Ta152 if are high over 20k