I realize that many animals have been killed with a .45 patched roundball and with .36 and smaller, but I am not impressed by that caliber roundball. I've shot mule deer with .45 PRB and did everything that I was supposed to do, shooting the animal broadside through the lungs while it was unaware of my presence at only 25yds and I waited over 30 minutes before quietly and carefully tracking it to where it lay. It was still alive so I finished it off. Field dressing it was where the disappointment came in - there just wasn't a lot of damage, compared to later .54 caliber kills and kills with highpower rifles. I was convinced that a bad hit elsewhere in that animal would have been very bad - not the clean kill that I absolutely demand of myself.
So, if I am going to be a careful and responsible hunter, I have to keep harking back to Robert Ruark's addage: "Use enough gun," and that means the fifties or larger with patched roundball. Of course, I live in Colorado where we have large animals. Mule deer can be pretty big. Elk are large animals and black bears can also get pretty big. These animals who live in the mountains have to really work for a living. Just moving around on the mountainsides is work, as many of you know from hunting out here and that makes the animal tough. Tougher, I would say, than crop fed deer in farm lands so bigger patched balls are required.
We supposedly don't have grizzlies and I'm really not interested in hunting them with patched roundballs until I'm diagnosed with a very bad terminal illness.
If you are looking for lots of internal damage use a 270. When the ranges are somewhat extended the damage gets even less. Even my 16 bore rifle with 140 gr of FF does not produce a lot of damage at range past 80 yards or so. But it kills stuff.
Shooting a mule deer with a 45 RB at 100 is not nearly as bad as shooting one with some modern rifle at 800-900 yards or more. This is the current fad in the west with some hunters BTW.
It goes back to WHERE ITS PLACED.
I like using a 50 for deer and figure its pretty light for Elk. But I would not pass up a shot on that account. Animals are not bullet proof. The trouble comes from misplaced shots and a bad shot with a ML or a BPCR or a modern HP can all be equally bad.
I once shot a deer with a BP loaded 38-40. 180 gr FP copy of the old factory bullet. Shot Mule Deer buck at about 40 yards, maybe less, deer ran the normal distance and piled up. Little bitty wound channels. Load was almost identical to the old factory loading. On average the deer would have run just as far had I made the same shot with a 45-70-350 or a 54 RB with 100 gr of powder. In fact I shot A mule deer doe at about 40 yards with my 16 bore rifle and it ran FARTHER even with the FAR, FAR greater internal damage. She was facing me and the shot made a huge hole where the top of the heart was. Massive instantaneous blood loss, easy blood trail (open grass land so I watched her fall) deer still turned 90 degrees and made 55 long steps.
The caliber needs to be ADEQUATE for the game. For deer a 45 has proven adequate. If the shot is placed right the deer will die in a few seconds. How far it travels in those few seconds? Thats up to the deer.
I have had them go 200 plus-minus shot with50 and 54 Rbs and pretty darned potent BPCRs, heavy hits, well placed. Deer can cover a lot of ground before the brain winks out due to lack of oxygen.
Most people that drop deer in their tracks with MLs are shocking the spine. Few modern rifles, unless they really mess up a lot of meat, will drop a deer with the bullet only striking minor bones, muscle and organs like liver, lungs or heart.
So use an ADEQUATE caliber and PLACE the shot. This is by far the best advice.
Dan