You are putting people on wayy too tight ranges, especially someone unknown like this guy. J7 and 73 were definitely possibilities, and don't assume someone is overplaying a hand. even if his range was JJ,77, and J7 only you'd still call because you are getting 2:1 (there are more combos of J7 than 77 and JJ). I think his range is more like AJ and KJ (less likely), JJ, 77, 33, J7, 73 and then a few weird crap hands/bluffs.