I shoot a couple of .62-caliber (20-bore) muzzleloadering rifles and consider them suitable for anything in North America. I know that 8-bores and larger were considered suitable for elephant. I am curious as to what size game the smaller than 8-bore (10-bore, 12-bore, etc.) bore rifles (muzzleloader and black powder cartridge) were considered generally suitable for.

You will read in history of gents who used an 8-bore for general purpose. I have shot two American bison with a 4-bore double that dates from 1890. I had a moose called in a few years ago with my 8-bore but it was not legal size.
They are great fun!
Cal

Thanks Cal. What about the smaller bore sizes? Were 10-bore or 12-bore considered adequate for cape buffalo for instance, or was the 20-bore considered a general use rifle? Inquiring minds need to know!

Both 10s and 12s were loaded to buffalo levels and white tail levels. Many of the 12s and 20s were used for deer. Have you seen my book on the bore rifles? 416 glossy pages of 28 up to 4 bores.
They will do the same today with either black or smokeless. Fairly easy to calculate loads for bore rifles with Blue Dot powder.
Cal

Thanks Cal. I have now that you mentioned it. Looks like I need a copy.

I have seen a 12 dram Holland Double 12 bore which weighed almost 14 pounds. That was built as an elephant rifle. Balls were alloyed and heat treated which were very functional.
I once shot a whitetail with an 8 bore through the front chest. The bullet exited his hind quarter with a huge hole and lodged in a cherry tree. The deer flipped completely backward.

If the rifle was built big enough to handle the charge, almost any could be used for large game.

Back in the late 1970's I owned a Holland 12 Bore double rifle that weighed 16 lbs and was cased in its original case with bullet mold that took a 4 1/4" brass case. It was in almost new condition and was made for the Nawab of Bhopol. The original charge card in the case stated 10 drams. Could not afford to keep it and traded it off, I did talk to the guy who bought it and after he shot it he said the 10 dram loads had very little velocity increase from 7 or 8 drams. Thats probably why Holland and Holland has record of only one made (along with a single shot). The double rifle was an underlever hammer.

loud-n-boomer:
PM me for information on my bore rifle book or look on my website <calpappas.com> and Books by Cal on the navigation bar.

Also, I have a 12-bore double rifle if you're interested. PM for details.
Cheers,
Cal