3 years ago on a hog hunt in south Texas I had the same problem on a sow that thankfully was recovered by by another hunter in our group. I had Four heads that all either bent or curled up. I have taken a number of other animals(with a magnus head) though and not had that happen, so sum it up to shot placement, bone contact er whatever. I still have some but after shooting many different heads I've decided to try a new one again this year, the 145 grain grizzly- we'll see how it goes with them. Wish I knew they were guaranteed I'd have sent them back- oh well. good shooting