Action target has two dueling trees for various calibers. Just do a web search for ar500 targets and you will find a ton of offerings from all over the country. See if you can find one local as shipping isn't cheap generally speaking.
Ruger SR-22, Browning Buckmark Camper URX, Sig P250 2Sum 9mm, Beretta Nano, Winchester 101 Trap, CZ 512 Mossberg 500 Flex, Carbine MForgery, and soon a rifle length MForgery........and counting. Damn this is fun