I have, quite a few times. I did it a few years ago with a .30-30 Contender at 90 yards using a Nosler 150 BT. Hit about 3" below the spine, only ribs/lungs. Shot was behind the shoulder. That thing went down so fast into the grass he was standing in, I thought I'd missed. He was dead before he hit the ground. I have thought perhaps a chunk of rib hit the spine or something, but I'm betting not. Path of the bullet was sufficiently close to the spine that I'm betting on pressure wave affects to the spinal cord. Whatever was the cause, it was one of the fastest bang/flops I'd seen in a while, not even a twitch when he went down and nothing, but lungs.
This from McGunner.
I shot a rather large 8 pointer on opening day from a rocky perch about 100 - 125 yards from the slow moving, unsuspecting, browsing fellow using my 45-70, loaded with Hornady's (325's?). Hit him right above the left shoulder about an inch from the spine, cracking ribs. It appeared to have exited on the same side below the leg. The heart was intact. Well, this fellow was lifted about a foot or two off the ground and flipped over, lay still and after about 1 minute had a seizure, and was DRT. I waited about 15 minutes before I approached him. From my background, a seizure after trauma is pretty ominous. My post mortem had me thinking that the shockwave must have affected his spinal cord as his heart was intact. I was 4.5 miles in. Took me 6 hours to drag him out.