MH I wager your bear had a number of large blood vessels torn up by the bullet. Being close to the heart they were large volume vessels and dumped a lot of the blood pressure very quickly. Any good bullet in the same place would likely have produced very similar results, regardless the caliber.
I have seen it many times with brown bears, as recently as a week ago. That was a 25-06 with 80gr TTSX on a smallish brown bear, tremendous blood vents and a very short, very wide blood trail.
When guiding I usually carried a 300WM for back-up and used it a number of times. It worked just fine. At the time I even thought better of several different bullets...
Mark Begich, Joaquin Jackson, and Heller resistance... Three huge reasons to worry about the NRA.
