The biggest buck I've ever seen was a huge mulie my grandfather shot in CO when I was about 10 which would have been about 1973. On that same trip my father took a run of the mill 3x3 mulie and if you didn't know better when they were hanging side by side you would swear one of them was a cow elk. The buck that my grandfather took had 6 pts on one side and 4 on the other. The outside spread was a little over 40".
He was so big that we actually took it in to be weighed which we had never done before. Field dressed, skinned with the lower legs cut off at the hocks he went 302 lbs on a certified farm scale. If he wasn't 400 on the hoof, he was damn close. I've still got the antlers off that buck in the barn on the old home place in CO. Someday I'll do a proper mount of them on a plaque. I've seen a lot of big mulies in my day but I've never seen on bigger than that buck. Truly a once in a lifetime deer.