I've made various spring targets out of AR and Hardox plate. They are convenient targets that you simply throw on the ground. The base is made from 3/4 flat bar with a 2x2 angle to protect the spring.
Here's a quick video I made of the target getting worked. The audio is crap( I used a simple point and shoot camera). You can see the bullet spatter hit the dirt at the base of the target. I used .45 acp hot loads 230 gr fmj.