45 Colt is one of my favorite calibers to load, shoot and hunt with. It has been getting the job done for over 130 years now. With modern propellants and projectiles it looks like it has plenty of life left in it. Here are a few posts I've gleaned from the various forums I haunt.
Count Zer0 wrote in the THR 1894 club;
"1894 Big 5 "edition" in 45 Colt. it goes well with my RBH in same caliber, except its chamber is larger than the RBH, so it works the brass more than I'd like.
Undisclosed load gets a 265WFN gas-checked lead bullet to 1450fps from said weapon, which was enough to pass thru about 30" of elk only a 2 weeks ago. My first elk, so you might say I like this rifle. This is one of those 45 Colt loads one should not attempt in Colts or replicas thereof, but it's good for 2" groups on average at 100yds with said bullets ( optics used ). The jacketed fodder will do better, but lever guns are inherently innacurate right? My hunting setup uses a Skinner peep sight, I pulled the glass after load development was done.
Anyway, I can't think of a better "brush gun" right now since mine is still all aglow!
My hunting buddy has the CB in the same caliber and got his elk with his using the same load. No bullets were recovered despite one going through both upper foreleg bones and the ribs twice. Those foreleg bones are the size of a quarter folks. Less meat damage than on the third elk in our party which fell to the classic 180gr 30-06.
From the Cast Boolits forum:
Stubshaft wrote -"I use the 300 in my Blackhawk w/4 5/8" barrel. I drive it about 750fps and although I have never shot a deer with it, it is death and destruction on hogs. I do try to stalk to within 25yds and have not needed a followup shot to drop one. The biggest hog to date with this bullet was 195lbs dressed."
Leadman wrote: "I shot an elk with the very similar Lee 310gr. RFN, muzzle velocity just over 1,100 fps in the front shoulders. Went all the way thru both shoulders, elk ran maybe 50 yards. Hole was the same size coming out as going in and that was with AC WW. These big heavy for caliber bolits don't need a tremendous amont of velocity. "
Old Vic wrote: "A couple years back I shot a muley doe with a .45 Colt out of a Ruger 4 5/8 barrel. It was a broadside shot at about 50 yards. At the shot, the doe fliinched, then trotted off a few yards before toppling over. The hit was through both lungs, with a thumb size hole going in and coming out. The bullet was a 300 grainer with a moderate meplate. I didn't know what the velocity was at the time of the shot, but when I chrono'ed them later, they were going 730 fps."
Veral Smith has a formula that seems to work in the real world, not just on paper.
He writes: "My displacement velocity formula is: Velocity times meplat width in thousandths of an inch divided by 4. Ideal DV range for big game is 100 to 125, 130 at the very max for fastest kills. At 100, wound diameter will average about 1 inch, at 125 it will be around 1 1/4 inch. If the wound diameter is 1 1/2 inch or larger in diameter the animal will normally run like it's tail is afire for 50 to 150 yards before expiring, though the shot is centered in the vitals. Yes even with a 4 inch diameter exit wound on a deer. Many will drop instantly with large wounds, if nerve shock anchors them, but many will run violently because blood flow is slowed by too large a wound. If wound diameter is 3/4 inch, about 85 DV, kills can be instant if well placed but some run can be expected. With a 70 DV, wounds will be about 1/2 to 5/8 inch. VERY deadly if well placed in the vitals, but some run is quite certain."
In another post he writes:
"First understand that it is NOT a theory. I would have let you call it a concept 15 years ago, but it is now a fact, proven over and over by thousands, and no one who has tried it has questioned it's accuracy since I published it in 1990.
The easy calculation is meplat diameter in thousandths of an inch X Velocity divided by 4.
Ignore the range you'll expect to be shooting at. Just calculate it off muzzle velocity and it will be close out to as far as most can hit with a revolver or rifles which thrive on 'Pumpkin ball' type bullets.
Get the DV up to 80 minimum, for quick kills on deer and larger game, best with 100 to 125. Don't go over that very much or kill speed will go down.
If using a small caliber gun which doesn't have the omph to get the 80 minimum desired DV, you'll get good clean kills at DV's down to 60 if the bullets are placed into good vital areas of the chest. i.e. If they cut major blood vessels, heart, or the thicker parts of the lungs.
Expect approximate wound diameters straight through the muscle and organ parts of game as follows:
60 to 70 DV 1/2 inch diameter
75 to 90 DV 3/4 inch +
100 DV 1 inch +
125 DV 1 1/4 inch +
If wound diameter goes up to 1 3/8 inch or greater kill speed drops off rapidly, which means game runs quite a way before expiring. With a DV of 100 to 125, game up to elk moose and bison almost always fold in their tracks or take a few steps at most."