What about cartilage piercings (rook, helix, tragus, conch, industrial, etc.) with a piercing gun?

That’s not true. Absolutely not. Piercing guns can cause your cartilage to rip or shatter due to their blunt force. Several places have enacted laws banning the use of piercing guns on cartilage. You can learn more about ear and nose cartilage piercings by reading Ear and Nose Cartilage Piercings: Pain and Care.

How does healing time differ depending on the method used (gun vs. needle)?

Studies verifying anecdotal evidence on this subject have not been funded by reputable organizations. According to most experts, however, thanks to better needles and more accurate positioning, these piercings are likely to heal faster, without infection or complications. You can find more information on how long it will take a piercing to heal by reading How Long Will My Piercing Take to Heal?

Is it possible to use a sewing needle in place of a piercing needle?

There is no reason to do something simply because it is possible. Consider these reasons:

• Hollow piercing needles are always used by professionals since this allows room for the jewelry to be inserted. Rather than just cutting into the skin and pushing it aside, they remove a small plug of skin.
• A variety of piercing needles are available, customized to fit specific piercings, and are pre-packaged and highly sterilized.
• The needle in your old sewing machine may be made of what you don’t know, but a professional piercing needle is usually made of high-quality, surgical stainless steel.