Early firearms came in two types: low-precision back-mounted shotguns that could be fired while moving, and high precision rifles that could be stored on the back but had to be removed and mounted on a bipod or similar to aim and fire.
The high-precision types more or less resemble human rifles or handguns. Yinrih can hit a stationary target well enough, but have lower accuracy compared to humans when fast-moving targets are involved. Electronically-assisted target tracking would eventually close that gap.
Over time, the shells used in shotguns were equipped with secondary explosives. A more conventional firing mechanism launched the shell and primed the secondary charge in the shell itself, which detonated downrange, dispersing the shot much closer to its target. As often as not the payload was something other than shot, such as powder or liquid chemicals that hindered or immobilized the target, allowing a more accurate firearm to pick off the target more easily at a distance, or the shooter to walk up and stab or smash the target with impunity.