bigfoot

First post!!; hi guys and gals :-) Any one know why a 22-250 60gn soft point would put a 3mm deep dent and bulge the back on a bit of ar500 ( hasten to add not one of yours!!!) Shot it at 120 yards, 50gn vmax did nothing but chip the powder coat, as did the 243 100gn soft point. Didn't try it with the 270 after that!!!!