Thanks for your answer.
That's exactly what happens sometimes, and sometimes the hole can get plugged by fat, or even a piece of torn muscle. Which is why I made my previous post about magic bullets that are always supposed to leave a blood trail. In my experience there is no bullet that leaves a blood trail all the time, though some will do it most of the the time.
If I really truly think a blood trail is a necessity for deer hunting, I tend to use a rifle in a caliber much bigger than .30, say at least .35, and a bullet that will penetrate all the way through all the time. I have seen too many .30 caliber bullets not leave an immediate blood trail, even though they penetrated all the way through and killed the deer reasonably quickly.
If the terrain and vegetation are such that tracking or retrieving a deer might be a problem, then I also tend to shoot them 2/3 of the way up, through both shoulders and the spine. This will work even with some pretty small bullets; my wife killed a good-sized Montana whitetail with exactly that shot (he was on the edge of some thick woods) a few years ago with a .240 Weatherby and a 100-grain Nosler Partition. It broke both shoulders and the spine and exited, and the buck was down and out right there. But it might not have left a blood trail.
