ea Hurricane was not that far away from Zero in raw performance, especially the Mk.II, it should outclimb it under 10000-15000 ft, though. The 8 .303s ammo will last much longer than the 60 rd for the Zero's cannons. Radius/endurance is lacking.
But you will need a lot more of them to bring down enemy. .303 were found to be ineffective, even against unprotected fighters of 1939-1941 period. Besides, you really miss the point with 20 mm in Zero, they were not a weapon to spray&pray like machine guns, they were there to finish the opponent when close. The main armament of A6M were 7.7 mm Type 97 machine guns. Even Saburo Sakai admitted that most of the aircraft he shot down by using his machine guns, while 20 mms were used to deliver the killing blow.
You're right that Zero had the great rate of climb, acceleration and that was manuverable. The shortcomings still stand, though.
It had shortcomings, it is known and I do not negate that. However having superior performance allowed pilots to disengage if opponent could threaten them. Japanese also used if possible altitude advantage.
There were other Japanese companies more than eager to sell fighters to the navy. Plus, why go with dedicated float plane fighters that kawainshi was doing - come out with a plain vanilla fighter and attach the floats on those, as with the Rufe. Why go with J2M that is not a carrier fighter 1st, then produce the land-based version? Too much of the resources and time was wasted from IJN (and IJA), with apaling number of aircraft produced.
Which ones ? The major contractor was Mitsubishi. Nakajima was already focusing on delivering Zeros as well, being forced by Navy. They also had to split their time and effort making naval torpedo bombers, Army fighters and bombers. Kawasaki was relatively smaller company if compared to major "players" and had more experience with inline engines, thus was tasked with work on Type 3 fighter and Type 2 Twin-engine fighter.
What is left is Aichi, which was doing more than a good job delivering dive bombers (in particular they were focusing on new D4Y Judy) and Kawanishi having no experience with fighter aircraft, but only with seaplanes and flying boats. Kawanishi soon was given a chance to produce something and the first effects were disappointing as N1K1-J did not meet the expectations and it wasn't until 1944 with N1K2-J that Kawanishi finally produced a superior fighter.
It was Navy that had to issue the requirements first, for the new fighter and as a result Mitsubishi would respond.
About J2M, it may look useless but Navy had their own bases and targets to defend and needed a land based fighter aircraft. It may look weird, but that was the specific of their policy. One would ask why Americans had at the same time present 6 types of fighters over Pacific - F6F, F4U, FM-2, P-51, P-47, P-38 ?
The zero's were outfitted with wing HMGs plus cannons, so there was plenty of space in Zero's wings.
You're talking about A6M5c, with 13.2 mm HMGs. But they were place on the outer side of the wing, and most importantly they were shorter. Type 99-2 was relatively long, and ammo boxes were placed deep in wing structure. Look for some technical drawings and you will see how exactly the placement of those weapons and ammo for them looked like.
The weight difference between Kinsei 50s and Sakae 21 is a mere 19 kg Ditch the fuselage LMGs their ammo and one saves weight. The A6M8 was to have the Kinseis, so this is the case of proof is in the pudding
Well, you try to sound like you know better than a man who designed that aircraft. This sounds a bit arrogant. Let me quote you exactly what Jiro said about choosing the Zuisei over Kinsei :
Only when the engine has been selected can a designer produce a draft of the airframe. In case of Prototype 12 (12-Shi - prototype name of A6M) the Mitsubishi Kinsei Type 46 and the Zuisei Type 13 were listed as candidate engines, the Kinsei being the more powerful of the two. If we used the Kinsei, we could have an airplane with high performance and high speed in one jump. For just that reason I felt it should be selected. This was in keeping with my philosophy that it would be better to design a high performance fighter in one big leap rather than to eventually reach that goal by making numerous small improvements to a lower performance aircraft over the span of its lifetime.
But there was a fateful obstacle in using Kinsei: it required a bigger airframe. The Kinsei was more powerful than the Zuisei, and it also was larger, heavier, and consumed more fuel. Because of this the airframe would be larger than if a smaller engine were used, and the fuel weight would be greater. In order to carry the increased weight, the wing must be larger and the fuselage and tail would also have to be larger. This, in turn, would require a stronger landing gear and yet another increase in airframe size.
A quick weight estimate showed the airplane's weight would be about 3000 kg. This was acceptable for a land-based plane, but pilots accustomed to flying small 1,600 kg Type 96 fighters would not readily accept the heavy new fighter. And this would mean the loss of the Prototype 12 contract. In contrast, if we used the Zuisei engine, the airplanes weight was estimated to be about 2,300 kg, the wing span would be in the neighborhood of twelve meters with a wing area compatible with a good fighter performance.
Aircraft is always a compromise, and engine being a heart of the warbird affects all other systems - heavier and larger engine requires stronger and larger airframe, rises the amount of fuel that has to be carried to maintain the range, etc. etc.
Besides, ditching fuselage machine guns would be out of question since they were requirement. I agree that they were obsolete, would be so much better if Navy could use Army 12.7 mm Ho-103 machine guns, especially that they were of similar size and weight, thus would not require changes in cowling construction.
A6M8 was an act of desperation. And according to the books I read the effect of more powerful engine was negated by added weight of armor, additional weapons and ammunition gained through A6M5 series and new engine weight - aircraft reached 563 km/h at 5600 meters - so was as fast as A6M5 due to increased drag. It could reach 6000 meters in 6 minutes and 50 seconds, being about 10 seconds faster than A6M5. The weight increase was tremendous though - from 3080 kilograms of the A6M5 to 3800 kilograms. This of course affected handling, landing speed and stalls.
Point of Zero was a light, maneuverable and fast climbing airplane. This was basically negating all the characteristics.
They still went with Kinsei eventually
Desperation, desperation ... they also went for Kamikaze attacks and balloon bombs...
I've suggested the compensation. The biggest compensation would be the better performing Zero, hopefully now with at least some armor.
A6M5c had armor and self sealing fuel tanks - that was a 8-10 mm thick armored plate behind pilots back and 55 mm thick bulletproof glass behind pilots head.
I'm also not sure if people are aware, but A6M5s produced by Mitsubishi from December 1943 (S/N 4274 and onward) and by Nakajima from February-March 1944 (it is known that the 96th Nakajima A6M5 in the collection of the Imperial War Museum in the UK produced in mid-March 1944) were equipped with automatic CO2 Fire Extinguishers. That constitutes (at least in theory) for over 750 A6M5s from 1150 produced by Mitsubishi and around 700 produced from 820 by Nakajima being equipped with Fire Extinguisher.
It was a simple single use equipment, required only activating by pilot and than would work automatically - when fire was detected it would release through pipelines a CO2 and spray it around the burning fuel tank. Pilot was aware of fire and its extinguishing by the panel placed in cockpit, which indicated fire by lighting a small lamp, when extinguished the lamp would be turned-off.