I just don't see the issue here. Self healing rubber targets are not 100%, and you are not getting penetration. At the end of the day you are just shooting at a chunk of metal. As I understand, AR500 is a treatment to the steel. perhaps therein lies the issue. I'm not a metalurgist, hower, I remember in 4x4ing a kit of chassis builders had lots to say about the manufacturing process of steels and proficiency of welds. Perhaps the AR500 in this case isn't perfect. but it's just a steel square...shoot it til it's destroyed.