The invincibility of tanks has little to do with how far the guns hit. Take T28 as an example:
The T-28 medium tank weighs 32,000 kilograms, 7.44 meters long, 2.86 meters wide and 2.86 meters high. The power plant is M- 17L V- 12 372 kW gasoline engine, which can reach 1400 rpm. The maximum highway speed is 37 km /h, which is the fastest of its kind. The off-road speed is 20km /h and the road journey is 220km. Armor protection is 80mm thick and 20mm thin. T-28 tank adopts multi-wheel suspension device, with rollers in front and driving wheels behind. The disadvantage of this suspension device is that the tank is easy to get stuck in mud.
Some investments in air and sea cannot be solved by spending money.
Take the air force as an example:
Engine technology, the most important thing is material engineering.
Aircraft engines require high accuracy, high speed and harsh working environment, and the key is high reliability.
Taking automobiles as an example, some key engine parts of domestic automobiles still depend on imports.
Some simply import the whole engine and only produce other accessories themselves.
And almost all of these are labeled as "domestic cars"
The automobile engine is still a civilian technology, while the aircraft engine has a strong Zheng Zhi factor.
Therefore, the import of its parts is simply "looking at other people's faces"
This is not to say that we can't make a qualified engine.
Because aircraft engines are produced in batches. At our level, we can only make one or two. If you want to produce more, there is no guarantee at all (Shen 567 is an example).
I hope you are satisfied with my answer.