The A6M5 was to be a temporary expedient until the replacement carrier based fighter, Mitsubishi A7M Reppu, was developed. As the A7M failed the A6M5 ended up being the most produced of the A6M series.
It was to be simplified for production and increase the diving speed. A heavier gauge metal was used in the wings. Diving speed was increased to 410 mph.
The prototype A6M5 (the 904th A6M3 converted) first flew in August 1943.
The A6M5 Model 52 prototype first flew in the summer of 1943.
Mitsubishi A6M5 Model 52a: March 1944
Mitsubishi A6M5 Model 52b: Middle of 1944
Mitsubishi A6M5 Model 52c: September 1944
Mitsubishi A6M5 Model 52: Had wing folding mechanism removed and a rounded tip was installed. Exhaust was modified and provided some extra thrust.
Mitsubishi A6M5 Model 52a, Mitsubishi A6M5 Model 52 KO: Ammunition feed was improved. Skin gauge was increased to allow faster diving. Diving speed was 460 mph.
Mitsubishi A6M5 Model 52b, Mitsubishi A6M5 Model 52 OTSU: Added armor for pilot and fuel tanks. A fire extinguisher system was added. The armament was improved. Added a 5 mm bullet resistant windscreen. Could carry two 150 liter drop tanks under the wings.
Mitsubishi A6M5 Model 52c, Mitsubishi A6M5 Model 52 HEI: Armament was revised. A self sealing fuel tank added behind the pilot which caused center of gravity problems. 8 mm plate installed behind the pilot. 55 mm of armored glass installed behind pilot's head. A 37 gallon self sealing fuel tank was placed behind the pilot.
Mitsubishi A6M5 Model 22: Fuel capacity was increased. Cannons were long barrel. The flaps and ailerons were modified. The skin was heavier gauge to allow faster diving.
Mitsubishi A6M5 Model 63: Centerline drop tank was replaced by bomb rack that could carry 500 lb bomb. The Model 63 could carry a 33 gallon / 150 liter drop tank under each wing.
The A6M5 entered service in October 1943.
It's best speed for combat was 180 mph or less.
On October 25, 1944, the Shikishima kamikaze sent five A6M5s to attack the St. Lo and sank it.