FMJs and ACCs bend. I bought an arrow checker because i have been using ACCs the past two years and always had an arrow or two that would not fly right. Bought a new dozen, checked all, all stratight. Shot a week checked again, two had wobble. After this year I'm going back to straight carbon. Now i'm shooting 78lbs with a heavy arrow, so i can see after a while some getting bent, but not after a week.