I made my own hanging plate rack.
I got the rack to leg brackets from a nice fellow shooter who also is a welder.
You can do a step better by buying shooting7's EMT rack pieces.
Whacking these plates with jacketed bullets when they are swinging, can launch jacket fragments right back at you - WEAR EYE PROTECTION.
Hopefully you can glean some ideas from my efforts
These are 6" diameter 1/2" thick AR500plates, zinc plated. I got them from shooting7 - my favorite steel supplier.
The 2"x4" is 6'. Each piece of 1/2" EMT is 5'. Each 1/4" chain piece is 12".
The plates are hung using 3/8" x 2" bolts with nylock nuts. Notice how they naturally hang kanted down. Also notice how the ground is chewed up underneath - thats from the spall.
Note: you have to expand the link of chain to pass through a 3/8" bolt - I used a punch.
The chain is 1/4" plated. The clip is nothing special, but big enough to hold 2 chain links. The bracket was built larger than a standard 2"x4" - the whole unit leans into itself to stay together.
The male bracket leg is held into the 1/2" ENT with a friction fit enabled by a short length of 1/4" bungee.
The zinc plating is a nice feature. This plate has about 50 handgun hits. I would not whack this with the AR15 as a miss would cut the chain, and the spall from swinging plates is very nasty.
This is an example of spall from hardcast bullets when the plates are swinging. Take spall seriously.