Piercing guns, which were originally developed for tagging livestock, are typically used for ear piercing, but may be used for other body parts as well. Piercing guns are generally not favoured by professional body piercers. Guns use relatively blunt, solid studs that punch through tissue; thus they cause more trauma to tissue than proper piercing needles, which are sharp and hollow. They are also considered unsuitable for hygienic reasons. Piercing with a piercing gun causes microsprays of plasma and blood; the guns frequently contain plastic components which are unable to be cleaned in an autoclave system, while surface cleansers do not kill all bacteria. Piercing guns are frequently encountered in retail outlets, where those wielding them may be inadequately trained. The Association of Professional Piercers recommends that piercing guns not be used for any piercing, including ears. Nevertheless, the vast majority of women in the west have their ears pierced with a piercing gun.

Source: Body Piercing - Wikipedia

I bolded the horrible bits, woo! But yeah, if you’re still willing to get pierced with an instrument that was made to tag livestock a piercing gun after reading that, you are seriously wrong in the head.