There are a lot of potential choices available. You might want to choose a good single action gun, like a good 1911 with adjustable sights, or maybe a Beretta 92 type weapon.
However, I don't get many chances at ground hogs, but have killed a lot of armadillos with whatever I had on me at the time. I have shot a bunch of them with one of my Glock 22's in 40cal but that particular gun has an aftermarket trigger and aftermarket sights, and is surprisingly accurate for a Glock.
A Browning Hi-Power could possibly be another choice, with a trigger job and good sights. My son in law has a Glock 19X that shoots lights out, perfectly capable of 50yd ground hogs. Another sleeper, is the old Taurus 92; I had one that I still mentally kick myself in the butt for trading off as it shot dead on at extended ranges with the fixed factory sights and had a great single action trigger.
You might have to go through a few guns to find one that really preforms well at 50 yds as two just alike might vary in performance. A decent trigger would be a good starting point, as well as adjustable sights, although I have had very good luck with fixed sights on some guns.