My Krieghoff .470 shoots 2" 4-shot 50 yd groups (2 x right & left in quick succession) repeatedly with both Hornady factory DGS / DGX and Federal Premium Sledgehammer and open sights.
Here is a quick 1.5 second right & left at 50 yd off hand: typical 1.75" group center to center. Plenty good for a .470 especially considering I can barely see the front bead anymore ;-)
I am pretty sure that off the sticks and with younger eyes behind it the gun can do much better ;-)