I have (4) of the knockdown style ones with 6" circles from Newbold mounted on a sawhorse setup on my personal range. They work ok for handgun and rimfire, with the right plate angle my .22 handgun will knock them down, and the bigger bore handguns have no problem on them. The .223 generally zips right through as mentioned and leaves them standing, I have a couple of the 2" ones that hang from a strap that move pretty well when hit with the .223.
I bought these as I thought it might be a simper and cheaper solution to knockdown plates then making my own knockdown rack(plus I wanted it now!), if I was doing it again and wanted it now I would probably just buy steel plates and hang them from chains or mount on stands.
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