...regularly, maybe like 1 in 500 or so. I used to multirep 275 but never did 315, however, I have at least 5 friends over the years that would multirep 315+ (one of my scout leaders/teachers quorum advisors growing up would do 405 sets of 5). He was a big dude.

I see people lifting that much on a regular basis when Im at the gym, so it's not that uncommon tbh