I wasn't comparing an arrow to any bullet, but noting that bowhunters take large bears inside 20 yards using a single shot weapon that has no "knock down power" and requires a lot longer to kill the animal.
In the past, I have posted the US Forest Service study on rifles for defensive use against bears, which ranked the .444 at the top. Another study I posted was a survey of bear guides and records of client kills. Interestingly, the .270 Win was at the top for one-shot kills, probably due to hunter skill and patience in shot selection.
If you read my post again, you will see that I said I would choose a my .375 H&H for intentional bear stalking. The fact remains that the .444 is, in the opinion of experts who have used it, superior to the .30-06 and .300 H&H. Its penetration through almost 3 feet of tight, wet magazines indicates to me that it would probably shoot through any bear at the angle one should be shooting. It is certainly capable of much faster 2nd and 3rd shots than a bolt action.
Here is an example of a .375 JDJ (necked down.444 Marlin )taking cape buffalo from a handgun:
http://www.americanshooting.com/American%20Shooting%20nine%20l.html
