Yeah 500 is a good estimate for the max bench that one could get without gear. I bet most never get to 400 even with hard work, due to injuries, size limitations, burnout, getting pissed at being stuck on the same weight forever when you hit the mid/upper 300s.
500 seems pretty stout without gear. That guy was the kid in school who benched 365 for reps sophomore year. I just couldn't imagine being able to push that kind of weight. I can't even get to 405!
my best is 315 at 230 and on gear! i suck at benching haha. dumbbells are a different story and better for bodybuilding in my opinion but then again im not a powerlifter or concerned about the poundage i move