Several historical sources note that some Mitsubishi A6M3 model 22 aircraft were modified to carry 30 mm high caliber Type 2 cannons instead of the standard 20-mm Type 99 used on all Zeros at the time. There is no direct confirmation in the documents, but it’s stated that the fighters received a Model 22b index and were based on Rabaul’s airfield, where they were tested in combat conditions. Sources lack any information about the combat effectiveness of this modification, the machines did not survive the war either. Presumably the idea of upping the firepower of the A6M3 with 30 mm cannons was eventually rejected because their recoil made piloting and aiming the light-weight Zero difficult and dangerous, due to the delicate and fragile wing construction of this nimble Japanese fighter. Moreover, Type 2 cannons were significantly heavier than Type 99’s, which changed the center-of-gravity, and caused declined maneuverability, range and dynamic parameters.
The Mitshubishi A6M3 experimental in game is a Japanese premium Tier V fighter. The greater armament weight makes it less maneuverable and dynamic than its regular A6M2 Tier V and A6M3 Tier VI siblings, but increased firepower more than makes up for this drawback. Contrary to the same-tier A6M2, this premium fighter is capable of destroying unsuspecting targets in mere seconds, and can still hold its own in a dogfight. 30 mm cannons can dish out a lot of hurt in short bursts and cause critical damage, so the A6M3 experimental doesn’t necessarily need to engage in prolonged fights with other fighters. Hunting altitude fighters and heavies might also be a worthwhile tactic since they traditionally pick fragile Japanese warplanes as their first targets. Quick maneuvers to evade their attacks and a powerful salvo to the back of an overzealous boom-n-zoomer can easily make them wish they never crossed your path. The main thing to remember when piloting this machine is that it is still a Zero, so its low survivability and high chance of fire will force players to fly carefully and not engage in mass fighting; picking single targets and preying on them is far more effective.