Hi, The polikarpov I-16 should have 2x7,92mm Mg in top Cowling, and 2x20mm Shvak guns in wing root. The I-16 was revolutionary when it appeared in 1933; the first operational cantilever monoplane fighter with rectractable landing gear. The original M-25 engine was a copy of the Wright R-1820; some I-16s were built in Spain and actually had US-built engines. It was very successful in the Spanish civil war; but it was obsolete at the outbreak of WWII. Large numbers were still in service in 1941, and it stayed in front-line service until late 1943. 7005 single-seaters and 1639 two-seaters were built. The last model was the Type 24, which could have a M-62, M-63 or M-25Ye engine, and several armament combinations including 12.7mm and 20mm weapons.
They could make it like the M.c 205 with optional armament like "4x7mm" "2x7mm 2x12.7mm" "4x12.7mm" "2x20mm" and "2x7mm and 2x20mm" As far as I know these combinations where used in I-16/24. 3x20mm was tested (1 in cowling and 2 in wing roots) but I have never found proof that it was used in combat.
