Why needle, not gun
A piercing gun forces a blunt stud through tissue by pressure. A needle removes a small core of tissue and leaves a channel for the jewellery to sit in. The first causes crush trauma the body has to repair around; the second does not. On cartilage the difference is not cosmetic: gun piercings on ears are a meaningful proportion of the cartilage infections a dermatologist sees.
Guns also cannot be autoclaved. The plastic housing that touches the ear is wiped between clients at best. That alone would settle it.
What the jewellery has to be
Implant-grade titanium, ASTM F136, internally threaded. Three specifics that matter and are worth knowing anywhere, not just here.
Implant grade because surgical steel is a marketing phrase with no fixed definition and most of it contains nickel. Internally threaded because externally threaded jewellery drags a screw thread through the fresh channel on the way in, which is exactly as unpleasant for the tissue as it sounds. And titanium rather than gold-plated anything, because plating wears through inside a healing channel.
The downsize, which is not optional
A fresh piercing is fitted with a longer post to leave room for swelling. If that post stays in after the swelling goes down, the jewellery moves in the channel, the channel heals crooked, and you get the bump that everybody blames on the piercing itself.
So the downsize is booked at the same time as the piercing and it is in the price. Four weeks for a lobe or septum, eight to twelve for cartilage. It takes ten minutes.