We normally make our AR500 Steel Targets 3/8" thick, which is suitable for most handgun and rifle calibers. These thinner 1/4"-thick targets are ideal for shooters of rimfire and small handgun calibers (9mm, 10mm, .40). They are less expensive, and lighter to carry into the field. We also sell round gongs in this thickness, here's the link.
Keep in mind that if these targets are left out on a range, it's certain that someone with a rifle or magnum-caliber handgun will ruin them. They'll last for years of suitable personal use.
NOTE: As of Feb 2018, these rimfire gongs are shipped with steel quicklinks (see photo) instead of nuts and bolts. They have smaller holes than the 'standard' gongs, and they can be hung with smaller chain, saving you weight and money. We sell a broad selection of hanging frames and tactical-style stands for mounting these targets. Spray-painted, usually red; if you have a color preference, just write it in the notes on checkout.
We sell several methods of hanging these targets; see the collection here.
Hole spacing: 4" square has a single centered hole. Gongs from 6" through 12" have two holes, 4" apart on center. Gongs from 14" through 18" have two holes spaced 8" on center. Gongs 20" and larger have wider hole spacing depending on size.