I have shot the 70gr Speer semi spitzer bullet in my 1 in 12" Ruger 77 mk2 and the same load in my Browning (1 in 12") Micro Medallion up to 200 yards and never seen a keyhole with neither one of them. I used 25gr of H4895, WSR, and 70gr SMPZ speer. Right about 2900 fps or so.
I have used the 60gr Nozler, 64gr win PP, 65gr boat tail gameking, and other, including cast and not one time have I seen a keyhole in both of those rifle.
I have a Rossi single shot that when I shoot any cast bullets, I get for sure at least one keyhole per group of 5-shot.
Camba