Steel for gongs, thickness AR or cold rolled

What type of steel should be used for the 3 gongs, AR, cold rolled?

What thickness plates are being used? I want to be able to see the plate move and hear the "tink" if I ever hit it.

Well heck. After posting this I found my answer.

THE TARGET — The targets are AR400 3/16″ thick rimfire gongs, an 8″, a 6″, and a 4″ gong. Each gong has a value, 1 point for the 8″, 2 points for the 6″, and 3 points for the 4″ gong.