Hey Tim64,
if you put 77 against 17 PFR into the equilator you will see you don't have the necessary equity against him and with the fact he's raising UTG tighter than average, you see you have an easy muck with 77.
I also think villain's range will be ~8%, but positional stats are always welcome. However for average adjusted reraises it's best to stick to the charts from the gold section and push according to them, when you don't have big enough sample size.
Your push might get profitable if opponent was folding lots of hands, but no half decent opponent will fold enough to make pushing 77 here profitable.
Regards,
burek2000