Several months ago, I added a 10 gauge steel plate to reinforce my shooting box and I thought this plate was more then enough to stop anything my air rifles shot. I found out I was totally wrong and I was able to shoot through the 10 gauge steel plate in 49 shots with my power tuned .257 texan. I was so confident this box would stop any rim fire round but now I will have to weld on a very thick plate of steel. Here is a post I did on this box I made https://www.airgunnation.com/topic/stuck-at-home/