Let's jump back to ammunition for 9mm.
I've seen recommended any quality barrier blind ammunition.
What about grain? I think federal has some that are only 124gr.
Obviously, bullet shape matters. I wouldn't want a rounded bullet bouncing off the bear skull. Flat, maybe wadcutter type.
I see speer gold dot, g2, and federal hst and federal punch. Not sure about other options... Those are the most common I see that are referenced as barrier blind
First, to clarify, my focus is on grizzlies, not black bears. Incidents between those two tend to be very different. Generally black bear incidents don't happen nearly as quickly or abruptly as grizzly incidents do, and incident for incident, aren't as difficult to deal with. For black bears, I'd be fine enough with whatever my normal carry ammo is. Maybe not the best choice, but not something I'd personally be concerned with. Since I live with both though, I focus on the former, as that's the most likely incident for me, where I live.
For the last year, I've been carrying Federal FMJ FP which seems to penetrate as well or even better than my hardcast loads. That said,
@Formidilosus has mentioned that the FMJ might tend to deflect off bone more easily than hardcast, which I did not test, but it makes sense. I have no illusion that I'd be able to count on a CNS hit, so that's not my primary concern, but it would be better IMO to reduce that possibility.
As an aside to planning on a CNS hit: Looking at the grizzzly skulls I have, the brain of the largest bear skull I have, about an 8' boar, is the size of my fist. Planning to hit that target in the time and speed these incidents typically happen, is unrealistic, IMO. Bonus if it happens, but it's very likely it won't, so also IMO, a good idea to have something that has shown itself to work well in the far more common scenario of COM hits, which is obviously a larger target by, literally, orders of magnitude and is hit far, far more often in actual incidents.
Given all that, IMO, something like the Buffalo Bore or Underwood 147 hardcast might be the best all-around choices. I don't remember where it was, but there was a bunch of penetration testing of Underwood hardcast ammo, from 9mm to 45 Super and everything in between. Surprisingly, to me, the 147 9mm and 250ish 45 Super out penetrated everything else, including 10mm. My thoughts are based on the premise that a deep, straight-line penetrating bullet is optimum, which really hasn't been tested, but regardless, has been show to work very well when used.
