What is the primary function of the wad in shotgun cartridges?

The primary function of the wad in shotgun cartridges is to seal the gases during firing. When a shotgun shell is fired, the powder ignites and creates gas that propels the shot (small pellets) out of the barrel. The wad serves as a barrier between the powder and the shot, allowing the gases to build up pressure behind the shot before it leaves the barrel. This sealing action ensures that the gases do not escape prematurely, which could result in a significant loss of efficiency and reduced range of the shot.

Furthermore, the wad often also provides some stabilization to the shot as it travels down the barrel, minimizing deformation and promoting more consistent patterns when the shot exits. While the wad has additional roles, such as holding the shot in place during handling and aiding in the proper loading of the shell, its most critical function is to ensure a proper seal for optimal firing effectiveness.