The Lehigh bullets do see
I have yet to shoot the Lehigh-type bullets but the data that is out there is very compelling. It really does seem to work as advertised.
For me, your suggested uses of FMJ is about spot on. In the end, a non-expanding HP will still act as a FMJ, theoretically. I believe that under penetration is the biggest deterrent to me. I do not live with North America's large Brown and Grizzly bears, but I do live with cougars, wolves, feral dogs, black bear and other vicious if smaller animals like badger. 12-18 months ago I shot a badger at under 15 yards with a .45 FMJ and it did not exit that little animals body. It died, but it did not pass through and to this day I have wondered if somehow I missed the exit hole, but I didn't. That bullet stayed inside and it made me rethink everything. I used to carry a Ruger LCP .22lr in my jacket pocket as something of a "backup". Not only is it too unreliable of a backup as it is a semi-auto and a rimfire(a centerfire revolver is the true belly gun), but then of course there is the underwhelming performance of .22lr out of 2" barrels.
For me, the use of FMJ/hardcast is for a few reasons. I believe that reliability of course is tops with RN bullets. I also believe that cast will shoot better than lead in 90%+ barrels. I love the 200gr. SWC in the .45 as it is accurate and effective, but reliability drops with the SWC profile. The .45 is in my opinion the "perfect" cartridge for defense because the diameter, weight and slow speed are an ideal combination for bipedal animals that are under 24" deep at the juicy bits. My only concern with HP's in the .45 for my personal situation is that they could underpenetrate on a wolf or cougar, but though they live right outside my door Oregon has neither a cougar nor wolf attack of a human in the record, ever.
