02. Then, with the improvement of casting technology, a circular solid shell consistent with the gun bore can be manufactured, and at the same time, the projectile can be developed into the form of small steel balls;
03. The penetrating power and destructive power of the solid shell are insufficient, and the oval shell appears, including the solid shell and the flowering shell;
04. The trajectory of the oval bomb is unstable and rifling occurs;
05. In order to improve the firing rate, breech guns appeared;
06. After the breech gun appeared, in order to simplify the loading, smaller caliber projectiles were made together with propellant, and fixed ammunition appeared;
07. Due to the development of fixed ammunition technology, the projectile was finally shaped into an approximate cone shape.
08. Solid bullets disappeared as live ammunition (bullets still exist), and flowering bullets developed into early armor-piercing bullets (AP) and early grenades (He);
09. In order to meet the needs of naval guns, an armor-piercing blasting bomb was developed, the essence of which is the intermediate form of armor-piercing bomb and Grenade. The makarov cap appeared by using a delay fuse (to enhance the armor-piercing ability);
10. In order to meet the needs of tank guns, solid armor-piercing projectiles for tanks appeared. The shells are steel-core or tungsten-core armor-piercing projectiles similar to solid projectiles, and at the same time, high-explosive projectiles (he), howitzers (including mortars) and armor-piercing projectiles are limited to cannon firing;
1 1. According to the theory of a Swiss scientist (forget who it is), hollow charge armor-piercing projectile (mainly used for rocket launchers and anti-tank missiles, see Baidu Encyclopedia for details) appeared, and metal jet described the attack mode of armor-piercing projectile;
12. The armor-piercing projectile (usually tungsten core) appears and the armor-piercing projectile appears at the same time;
13. Depleted uranium armor-piercing projectile made of waste nuclear fuel is essentially armor-piercing projectile made of depleted uranium alloy;
14. solid shells reappear as electromagnetic shells, and laser weapons appear at the same time.