A true 16 bore ball weighs 1 oz., 437.5gr.

A 17 bore ball, common THEN for loading in a 16 bore rifle or smoothbore, will run 411gr. in pure lead and Forsyth notes 16 is the minimum for dangerous Indian game, which includes tiger, buffalo and elephant.

Hardened, the ball's weight will be less than presented, by a little less than 20gr. This was "his" minimum.

Personally I would not hesitate to use a hardened 17 bore ball for Taylor's new Joseph Lang rifle, for bear hunting - grizzly or black bear.

I would however, prefer my 14 bore, or my buddy's 11 bore - all loaded with one 'bore' size smaller, hardened balls.

As to the 12 bore Brenneke's use on bears, it is, in my opinion much more suitable for that use, than the use of sub calibre sabot rounds that are loaded with .45 or .50 calibre pistol bullets.

The full sized (close to) hardened round ball will out-penetrate the Brenneke's most likely - I have not tested them, however the large flat nose of the Bren's and riveting due to soft lead will reduce penetration considerably.

If the Brenneke slugs are soft lead as I suspect, the the RB will be much better, however, if driven at similar speeds capable of the round balls with handloads 1,500fps to 1,700fps with smokeless), the factory Brenneke slugs will likely kill black bears more quickly, however that may only be subjective as DRT is DRT.

Lewis and Clark shot patched pure lead round balls and 60gr. of powder (issue ctg.) in their 1803 rifles. The ball weight for them was approximately 210gr. to 220gr. depending on exact size. The military usually used grossly undersized balls.

That is not even close to a suitable load for plains or wooodland grizzlies, in my opinion and is why THEY had trouble killing those bears with them.

The velocity for their issue load for the .54's was approximately 1,050fps.

I would much prefer a hardened 390gr. ball of .65" running some 1,500fps, thanks. That one will likely exit on a broad-size chest shot, and a shot into the chest of a standing bear, would certainly 'chink' the spine.

Now, if you want to talk about BIG grizzlies/browns, like Phil S. runs into in his chosen line of work, I would think 14 bore might be my minimum, but buddy Keith's l1 bore would be a more comfortable carry. A backup wheel-gun like a .460 or .500 S&W would also lend some comfort to that venture.