I still have some cardboard bowling pin targets that where being sold back in the 80's. I also cut one out of 5/8 steel plate, welded it to a old cars coil spring and used that for my rifle practice. Wow, the .223 would almost completely penetrait it! But it would bounce around when it was hit, pretty fun.
I remember my shooting buddy brought a M1 Garand to shoot the rifle match at Second Chance with! When he hit the steel pins they would smack the ground so hard you just had to laugh! Were as all the competitors shooting .223's would just flop over.
During his second attempt he set the range on fire!
sparks of the metal pins and that 30.06 blasting them started a little on range fire that the time keepers had to go stomp out.