Why should you NOT get pierced with a piercing gun?
Safety
It’s virtually impossible to properly sterilize a piercing gun. Some of them are made of plastic, which would melt in an autoclave. Even metal ones are generally just wiped down after use – which is not enough to entirely prevent the spread of bloodborne pathogens and other nasties.
It uses a single-size, post earring, usually 20 or 22 gauge with a butterfly back. These cannot be adjusted for size, meaning that if your lobe is particularly thick or if you have a lot of post-piercing swelling, you may not have enough room to accommodate the swelling. If that happens, you may develop serious problems that require you to remove the jewelry. A needle piercing is done with a barbell or flatback labret, usually in 18 or even 16 gauge, depending on the location. The larger gauge makes for a more stable piercing.
The backs are also a problem because butterfly backs are difficult to clean properly and can develop a buildup of gunk and bacteria. A barbell or flatback labret is easy to keep clean and doesn’t develop unsanitary buildup.
Post earrings have a blunt tip. A needle has a sharp point that slices right through the skin, whereas a piercing gun can cause blunt force trauma to your ear. If you’re getting a cartilage piercing, this can actually cause your ear cartilage to shatter.
Accuracy
A trained piercer will take the time to mark where the piercing will be and ensure that you are happy with the placement. With a gun piercing, the location is not marked in advance, and it is difficult to get a straight and accurate placement with a gun because it’s harder to see.
A crooked piercing rarely will heal well and with gun piercings, it’s more likely that you will have issues with angle and symmetry.
Jewelry Options
Stores that do gun piercings usually only have a limited selection of very basic jewelry to choose from. A professional piercing shop will have far more styles to choose from. You’re going to be wearing that jewelry for several months (even up to a year!) don’t you want to wear something you truly love instead of just whatever the store had on hand?
If you choose threadless jewelry, your style options are virtually unlimited, and you can use the same ends when you downsize the jewelry. (Or even use those ends in different piercings!)