Those beautiful, sharp edged holes were made by Hornady 300 gr round nose bullets shot with a muzzle velocity of about 2375 fps. If you look closely at the picture, you'll see little tears around the periphery of the holes.
I flattened out the torn edges of the holes so as to better measure the group. Actually, in the closeup that John Peterson provided, the holes don't show up so clean.
I wish the rifle and I shot that well all the time. All in all though, we do quite well most of the time. Ruger/H&H - it doesn't matter. There's basically no difference in performance. But the Ruger is a better fit in a Mauser 98 action.
And I don't tire of showing it.