Anyway, back to the bear threads … my interest is in handgun defense. This article (BULLET "ENERGY" (ft-lbs) VERSUS "TKO" EFFECTIVENESS ON BIG GAME) introduced new terminology (to me) called Taylor KnockOut (TKO). TKO calculations put bullet diameter, weight and velocity on equal ground, i.e. velocity is not squared as it is in calculating muzzle energy. Therefore, Muzzle Energy vs. Taylor KnockOut (TKO) basically concludes:
“Kinetic energy (muzzle energy) calculation is more meaningful with the small mammals, than with giant mammals.”
“…the TKO formula will generate a number that I believe is far more meaningful on big game, than ft-lbs of energy.”
So, I now think I finally have a better understanding the choice of hard cast heavy for caliber ammo selection for big game defense.
I updated my chart to include TKO numbers for 357, 10mm, and 44 with lighter, faster solid copper bullets, vs. heavier, slower bullets:
Even when I reloaded in AK, I never followed the TKO formula.
I figured a 500 gr cast out of a 458Lott doing around 1700fps (quite accurate, I may add) would work or even a 400 grain cast out of my co_pilot (take down 45/70) will also suffice. Never felt undergunned for bears or moose.
That’s 55.61 in TKO! I’d say you figured pretty good
I am a numbers guy by back ground, but I have learned shot placement and other variables are more important. However, I can’t help myself to cut and paste this from one of the links that shows how far down in TKO power the 22-250 is from your 45-70 and a 30-06:
Per physics, I find it hilarious to put bullet diameter on equal grounds to velocity, or to call velocity “energy” without squaring it…
Kinetic energy squares with velocity, this is physics. 0.5(mass) * (velocity^2). Kinetic energy is critical to determining terminal effect of a projectile
Although I don’t know John Taylor, I’ve met hunters that have traveled to Africa. The benefits of big game hunters in Africa versus the destructive wake of poachers is a world of difference.
That being said, it’s my understanding that the TKO formula was specifically developed for estimating how relatively long an elephant would remain down if a head shot failed to penetrate the skull before a hunter could approach for the final shot. Reusing an equation with that specificity of purpose might be problematic at estimating effectiveness for your scenario.
Instead, maybe read up on bear guides and hunters and what calibers they use. If I remember correctly, many years ago I came across an old government research paper for government surveyors in bear country that suggested a 44 Magnum carbine should be considered the very least powerful option for Bear defense.
True that their is a suggested minimum in caliber but I feel you carry what you can handle. If you cant fo quick follow up shots with a 44mag its useless.
Alot of folks can’t. I seen it at the range all the time (when I used to go to the range, some people are scary).
The 45/70 is popular in AK for good reason. Seen folks shoot it once and then have to take a breather before the next shot. That’s not gonna fly when a bear is coming at you. Give that same person a 357 carbine and he could crank out rounds accurately.
Heres a 300 gr hard cast 44mag I used to use out of our super black hawk in AK.
Dont remember the speed of the round but I was only good for 3 rapid fire shots out of the single action pistol. In a real charge, trust me you won’t get time for more.
Id let guys at the range shoot one if they wanted. Most are used to the standard 240gr. Few could crank off rounds rapidly.
When I look at those flat nose bullets I think about aerodynamics and how much harder they must hit than a round nose since they are non expanding. In other words, the round nose seems like it would pass thru much easier.
I used to do tests on what would penatrate the farthest. I would put water jugs in front of a log roughly 12” in diameter, sometimes bigger.
Obviously my lott and even the 45/70 would get complete pass through.
Pistol rounds were harder to figure out. I never shot 300 gr JHP’s to compare the cast. So apples to oranges. The 240gr’s couldn’t even touch the 300 even though they were going faster.
Rudimentary test but gives an idea. Id take a hard cast FP any day of the week for penitration. They dont clog or come apart. Dealing with a bear, with its thick skin, fat and hard bone, I want an exit. 2 holes bleed more than 1.
Of course, its all shooter preference.
Not worried about aerodynamics with a self defense round. Not shooting 100yards with this type of ammo. I have better ammo for that. These and similar were for hiking, etc where its gonna be 15 yards or so or less
Honestly I’m reading this thread and wondering what the actual F?
Kinetics are kinetics, 1/2 mass times velocity squared…. Nothing changes.
Of course the shape of a bullet will make a difference in how hard it “seems” to impact the target…
Why exactly do we carry hollow points instead of ball ammo in our carry guns?
Because the hollow point or flat tip “hard cast” round expands more within the target and transfers more blunt force energy into it, rather than piercing through at speed causing deeper expansion cavities and possibly passing through.
