Breech from Russian 122 mm M1910 howitzer, modified and combined with 105mm H37 howitzer barrel
A breech-loading weapon is a firearm (a rifle, a gun etc.) in which the bullet or shell is inserted or loaded at the rear of the barrel, or breech. It can se said that this is the opposite of muzzle-loading.
Modern mass production firearms are breech-loading (though mortars are generally all muzzle-loaded). Early firearms were almost entirely muzzle-loading.
The main advantage of breech-loading is a reduction in reloading time; it is much quicker to load the projectile and charge into the breech than to force them down a long tube, especially when the tube has spiral ridges from rifling.
In field artillery, breech loading allows the crew to reload the muzzle without exposing themselves to enemy fire, and it allows turrets and emplacements to be smaller.
The Process of Automated Breech Loading
The process outlined above is broadly similar across all automated breech loading systems.
Note for spotters: Note the modular charge system...