"Knockdown Power"

[Slamfire]

This video is full of crap. The bullet went though the eye sockets. There was a bunch of threads on this video on several forums back when if first came out. There is no way a near miss from a 50 BMG is fatal.

I agree. If it was, there would be no need for artillery and high explosive, which, if the war head goes off near by, will kill due to the blast. In spite of Dirty Harry claiming his 44 Magnum "will blow your head clear off", I am of the opinion that no small arm that a human can carry,hold, and shoot, will kill by concussive blast, unless it happens to have a fragmentation warhead. Now based on what I have read, from people who were there, if one of the pictured projectiles hits a human, even though these shells are only going about 2000 fps, the impact will cause a human body to fragment in pieces. If the warhead goes off, the blast will kill, within a radius measured in tens of yards, shell fragments have been known to shred a human body from hundreds of yards. The large eight inch shells are Naval shells, fired by Heavy Cruisers.



The five inch shell was the main armament of a Destroyer. The cannon firing such a weapon is a little too large for a man portable weapon.




The bullets we fire poke holes in objects. If they had enough momentum to knock over the target, they have enough momentum to knock over the shooter.

This topic, started by Hummer70, leads to an outstanding resource on lethality literature:

Why are slow moving heavy bullets considered to be effective?

https://www.thehighroad.org/index.php?threads/why-are-slow-moving-heavy-bullets-considered-to-be-effective.827939/

 

[mcb]

I think the 577 Tyrannosaur and similar cartridge probably do have "Knock Down" power in a way if fired at critters of similar mass to the poor dudes shooting the rifle in the video. Imaging getting hit with an impulse of that level unexpectedly. Sure if you are ready for it you could probably stay upright but if it hit you unexpected I bet most of use would be knocked down. Not to mention the hole it would put in you.

 

[jmr40]

I just can't see a 308 carryng 2684 ft lbs of energy packing more of a punch than a 270 Wby Mag carrying 3300 ft lbs of energy. Or even a 257 Wby carrying 2800 ft lbs of energy. Both smaller bullets (the 257 much smaller) but carrying more energy to release in the

You're using the wrong measuring stick. It is a combination of impact velocity, bullet construction, and shot placement that matter. Too much of any of those can be a negative.

Most bullets work very well if impact speeds are between 2800 fps and about 1800 fps. Assuming you have a bullet with construction that will allow it adequate penetration on the game hunted. I'm shooting a 178 gr bullet from my .308 at 2620 fps. That bullet has enough mass to give adequate penetration on any animal in the lower 48 and it is still moving at over 1800 fps out past 500 yards. Dead is dead. That bullet will kill anything I'll hunt out to 500 yards. Energy numbers aren't important. It is how deep the bullet penetrates and is it still moving fast enough to expand.

When shooting the fast magnums at close range you'll often have over expansion and poor penetration. Out to 500 yards I'm betting my 308 load penetrates deeper, and makes a bigger hole than the 257 or 270 magnum. The magnums will have less bullet drop, but that is easy enough for me to correct with a range finder and scope with multiple aiming points. The magnums will retain the necessary 1800 fps at longer ranges. But they aren't an advantage at closer ranges. We have to be honest and ask this question. How far can I shoot? Inside of 600-700 yards the under 375 caliber magnums don't offer much advantage. When you get to large dangerous game needing 375 and up it starts another discussion.

The old school way of doing things was to shoot lightweight bullets very fast in magnum cases The trajectory was flat, and muzzle energy numbers looked good. But modern high BC bullets and modern scopes are game changers. This is why the 6.5 Creedmoor is so popular. It is a very mild recoiling round. With 140-147 gr bullets it gives enough penetration for elk and moose size game. And the high BC bullets started at 2700 fps still penetrate and maintain the 1800 fps to expand out to about 700 yards. The magnums shoot flatter, but anymore that simply isn't seen as an advantage.

 

[Slamfire]

think the 577 Tyrannosaur and similar cartridge probably do have "Knock Down" power in a way if fired at critters of similar mass to the poor dudes shooting the rifle in the video. Imaging getting hit with an impulse of that level unexpectedly. Sure if you are ready for it you could probably stay upright but if it hit you unexpected I bet most of use would be knocked down. Not to mention the hole it would put in you.

I am not going to fire that!

 

[CraigC]

No such thing as "knockdown power" but we know what they mean. That said, there is no measuring stick. Kinetic energy is just a marketing tool for selling velocity. There is no mathematical formula that will tell us what we want to know. There are too many variables and too many ways to measure success and failure.

 

[Tiro Finale]

Ah, the mythical "stoppn powuh". In my neck of the woods, people practically live by that phrase.

"What gun should I carry?"
".45 because of stopping power."

"Which rifle should I use for hunting?"
".30-06. Anything less doesn't have enough knockdown power."

The truth is that very few (if any) bullets will truly knock a person or animal off their feet. They are simply too small. The bullet would have to be the size and shape of a soup can to do that. Additionally, many bullets are too fast. They tend to punch through the target and retain a good bit of energy afterward.

 

[Tiro Finale]

H

I think the 577 Tyrannosaur and similar cartridge probably do have "Knock Down" power in a way if fired at critters of similar mass to the poor dudes shooting the rifle in the video. Imaging getting hit with an impulse of that level unexpectedly. Sure if you are ready for it you could probably stay upright but if it hit you unexpected I bet most of use would be knocked down. Not to mention the hole it would put in you.

I wonder if I could get that in an Encore. Y'know, for carry.

 

[Bigmike79]

If we are talking about perforating homogeneous steel armor then it become easy. Kinetic Energy will be directly proportional to the thickness of armor a particular weight and caliber AP projectile can perforated. Lethality on living critters is never that simple...

Obviously lethality on living critters has more variables than shooting a piece of armor, but when playing the law of averages, the more powerful the round is, the more lethal it is providing we're comparing apple's to apple's ( bullet size, design, type of animal, shot placement etc)

If you shoot 100 bucks with a 308 and a 300 mag pushing the exact same bullet weight and design, the 300 mag is going to result in faster kills on average. You might be overthinking it.

 

[mcb]

Obviously lethality on living critters has more variables than shooting a piece of armor, but when playing the law of averages, the more powerful the round is, the more lethal it is providing we're comparing apple's to apple's ( bullet size, design, type of animal, shot placement etc)

If you shoot 100 bucks with a 308 and a 300 mag pushing the exact same bullet weight and design, the 300 mag is going to result in faster kills on average. You might be overthinking it.

I was trying to mitigate everyone else from over thinking it, in my rambling way. I agree with you whole heartily. More energy is rarely a bad thing. Unless your bullet can't handle it. There are cases where a fragile bullet actually works better at a lower impact energy since if it hits with to much energy the bullet structurally fails so badly that you end up with a very nasty but shallow wound. But that is rare as most manufactures load the bullets within their capabilities. -rambling again...

 

[readyeddy]

I would go with the opinion of dangerous game hunters. They need to use a cartridge that will reliably anchor animals that are often very large and hard to stop or else end up getting killed.

 

[CraigC]

Ah, the mythical "stoppn powuh". In my neck of the woods, people practically live by that phrase.

"What gun should I carry?"
".45 because of stopping power."

"Which rifle should I use for hunting?"
".30-06. Anything less doesn't have enough knockdown power."

The truth is that very few (if any) bullets will truly knock a person or animal off their feet. They are simply too small. The bullet would have to be the size and shape of a soup can to do that. Additionally, many bullets are too fast. They tend to punch through the target and retain a good bit of energy afterward.

"Knockdown power" is a myth. "Stopping power" is not. Two different things. The former implies that a bullet striking a target will "knock" it down, which is absurd. The target may go down but the bullet didn't "knock" it down. Bullets do indeed "stop" critters, most notably in stopping the charge of dangerous game animals. Where it's generally considered that bigger is better. The trick is figuring out how to accurately quantify it.

But that is rare as most manufactures load the bullets within their capabilities. -rambling again...

I don't consider it rare at all. Far too common, in my opinion. The problem is that most people are killing deer, which requires very little of a bullet and they consider a dead animal to be a success, regardless of what the bullet actually did. In other words, complete and utter bullet failures go unnoticed as long as the critter died shortly after being shot.

 

[hdwhit]

CptnAwesome asked:
Wanted your opinions on what some hunters refer to as "Knockdown power".

No such thing.

No relevant industry or professional organization has posited an objective definition for any metric known as "Knockdown Power" or anything that would be synonymous with it.

We can spend eternity here talking "off the cuff" about what it might mean, how we might want to define it, how we might want to measure it, how we might want to compute it, but until someone comes up with a metric that can be closely correlated to actual "knockdown results" (whatever they may be - we haven't defined them yet) we'd simply be talking a mixture of fantasy and wishful thinking with no test in reality.

 

[CptnAwesome]

You would think that a 50 BMG through the eye sockets would sorta blow the thing's head up like a grapefruit. You never now though. I've seen a pig shot through the eye sockets with a 7.62x39 FMJ bullet, and it was pretty gory. the exit side looked like someone carved the things eye out with a spoon, and there was tissue coming out of the the snout.

Makes me think of a few years ago when I shot a groundhog at about 70yds with a 22-250 with a Rem Core lokt. He was on all fours broadside and I made a head shot, he never moved.

When I got to it I thought it was still alive, looked like it was never shot, still looked perfectly normal except for a very slight drop of blood coming out of the opposite ear. Felt the head and skull was busted inside but other than that looked perfectly normal. I couldn't believe it.
Only think I can come up with is that in entered and excited through the ears, I would have thought it would do more damage though

 

[Bigmike79]

Makes me think of a few years ago when I shot a groundhog at about 70yds with a 22-250 with a Rem Core lokt. He was on all fours broadside and I made a head shot, he never moved.

When I got to it I thought it was still alive, looked like it was never shot, still looked perfectly normal except for a very slight drop of blood coming out of the opposite ear. Felt the head and skull was busted inside but other than that looked perfectly normal. I couldn't believe it.
Only think I can come up with is that in entered and excited through the ears, I would have thought it would do more damage though

We had a rabbit that died from an invisible bullet when I was a kid. I was arguing with my mom and in mid argument she said "go get your 22. That rabbit is back in the garden." I ran downstairs and grabbed my bolt action Steven's 22 and a handful of shells before running around the back of the house so I could get a clear shot at it. Pow, I shot the thing center mass and it jumped in the air before trying to crawl off. By the time I got to the thing it was dead. I grabbed it by the feet to take it into the shop to skin it, and there was no movement. Now this is where it gets strange. I examine the thing to see where I exactly hit it, and I can't find a wound. There wasn't even any blood. It was the weirdest thing. I couldn't even find a hole in the fur after I skinned it.

After all these years, I think you might have just solved the mystery. I wonder if I put one through it's ears and there just wasn't much external bleeding?

 

[Kano383]

When you shoot an animal, the recoil you feel is exactly the “knock down power” exerted on the target - if the bullet stays inside. You’re not going to knock down anything or anyone, unless you use grossly disproportioned calibers (600 NE on a rabbit, anyone?).

Energy figures are a very poor predictor of wounding capacity and lethality: the bullet’s mass, shape, and behaviour in tissues and bone are much more important.

Nobody would seriously tout the .22 Mag as a deer round, yet If you consider that a .22 Win Mag bullet shot at a white-tail is comparatively five times bigger than a .450 Nitro Express bullet shot at a bull elephant, you’ll grasp the futility of the “knock down” expression - and appreciate the wisdom of placing your round where it counts if you want to avoid an altercattion with a pissed-off pachyderm, which is generally not a winning proposition.

As many have said above, the only “down” switch in an animal (or human) is the CNS. Short of a direct CNS hit, a good size bullet will let the oil out of the machine faster than a smaller/slower/lighter one, and do more damage to the cogs, but that’s about it.

 

[entropy]

yet If you consider that a .22 Win Mag bullet shot at a white-tail is comparatively five times bigger than a .450 Nitro Express bullet

Neither in mass or volume is a .22 WMR bullet bigger than a .450 Nitro bullet, and I suspect the velocity need to to equal the KE would cause other problems, like the lead melting from the friction and the subsequent collapse of the jacket. One could, I suppose, if one were equipped to load .22 WRM, load an elongated bullet that would equal the .450 NE bullets' weight, but due to the .22 WMR's case capacity, and relative case weakness, I wouldn't recommend firing it.
I own neither of these calibers, but here's some numbers:
Win. S22RM .22WRM: 2120 MV 339 ME 34 gr. bullet
Kynoch 400 gr. solid 2150 MV 4110 ME
So what i'm getting from this is the MV's are almost identical, the .450 bullet is 11.11 times the weight of the .22WMR bullet, and the 450's ME is 12.12 times the .22 WMR's ME.

 

[CraigC]

Neither in mass or volume is a .22 WMR bullet bigger than a .450 Nitro bullet...

I suspect he's talking about in relation to the size of the critter. Which can also be taken to mean that shooting a squirrel with a .22LR is about like shooting deer with a 105mm.

 

[boom boom]

I think the 577 Tyrannosaur and similar cartridge probably do have "Knock Down" power in a way if fired at critters of similar mass to the poor dudes shooting the rifle in the video. Imaging getting hit with an impulse of that level unexpectedly. Sure if you are ready for it you could probably stay upright but if it hit you unexpected I bet most of use would be knocked down. Not to mention the hole it would put in you.

Reminds me of the old saw that the ___________ cartridge ( fill in the blank), kills at one end and seriously maims at the other. You want a step up, get a recoilless rifle.

 

[entropy]

I suspect he's talking about in relation to the size of the critter. Which can also be taken to mean that shooting a squirrel with a .22LR is about like shooting deer with a 105mm.

Perhaps it could have been worded better. "Relative to the size of the game, the ......." would have clarified that.

 

[Kano383]

Neither in mass or volume is a .22 WMR bullet bigger than a .450 Nitro bullet, and I suspect the velocity need to to equal the KE would cause other problems, like the lead melting from the friction and the subsequent collapse of the jacket. One could, I suppose, if one were equipped to load .22 WRM, load an elongated bullet that would equal the .450 NE bullets' weight, but due to the .22 WMR's case capacity, and relative case weakness, I wouldn't recommend firing it.
I own neither of these calibers, but here's some numbers:
Win. S22RM .22WRM: 2120 MV 339 ME 34 gr. bullet
Kynoch 400 gr. solid 2150 MV 4110 ME
So what i'm getting from this is the MV's are almost identical, the .450 bullet is 11.11 times the weight of the .22WMR bullet, and the 450's ME is 12.12 times the .22 WMR's ME.

Comparatively bigger...

A whitetail is 120-150 lbs, a .22 mag bullet is 30-40 grains. A bull elephant is 10,000-12,000 lbs, a .450 NE bullet is 480-500 gr. Do your math...

All I said was that throwing a 500 grainer at an elephant is sending a much smaller projectile compared to the size and mass of the animal than throwing a 40 grainer at a whitetail. And I guess this puts elephant hunting into perspective...

 

[Klint Beastwood]

When you shoot an animal, the recoil you feel is exactly the “knock down power” exerted on the target - if the bullet stays inside. You’re not going to knock down anything or anyone, unless you use grossly disproportioned calibers (600 NE on a rabbit, anyone?).

Energy figures are a very poor predictor of wounding capacity and lethality: the bullet’s mass, shape, and behaviour in tissues and bone are much more important.

Nobody would seriously tout the .22 Mag as a deer round, yet If you consider that a .22 Win Mag bullet shot at a white-tail is comparatively five times bigger than a .450 Nitro Express bullet shot at a bull elephant, you’ll grasp the futility of the “knock down” expression - and appreciate the wisdom of placing your round where it counts if you want to avoid an altercattion with a pissed-off pachyderm, which is generally not a winning proposition.

As many have said above, the only “down” switch in an animal (or human) is the CNS. Short of a direct CNS hit, a good size bullet will let the oil out of the machine faster than a smaller/slower/lighter one, and do more damage to the cogs, but that’s about it.

No reason to go that high in caliber. I shot this rabbit from 500y with a .300 win mag as it mosied on by the gong I was setting up on, decided to check my cold barrel on a moving target.
I knocked it down. And skinned it in one shot. Hashtag efficiency.

 

[Slamfire]

No reason to go that high in caliber. I shot this rabbit from 500y with a .300 win mag as it mosied on by the gong I was setting up on, decided to check my cold barrel on a moving target.
I knocked it down. And skinned it in one shot. Hashtag efficiency.

Oh my God, you killed the wabbit!

 

[M118LR]

Wanted your opinions on what some hunters refer to as "Knockdown power".

I have a good friend that's very partial to the 308 win. And rightfully so, it' an awesome round especially for whitetail. BUT... anytime I mention a caliber with a smaller bullet he's quick to say "308 got more knockdown power". I assume he believes this cuz it has a bigger bullet.

I stopped using the term a long while ago, I just refer to energy. From my thinking energy = knockdown power. I just can't see a 308 carryng 2684 ft lbs of energy packing more of a punch than a 270 Wby Mag carrying 3300 ft lbs of energy. Or even a 257 Wby carrying 2800 ft lbs of energy. Both smaller bullets (the 257 much smaller) but carrying more energy to release in the animal.

Seems simple to me but but I've been wrong once maybe twice before.

What do y'all think?

I think we need to consider the size of the game animal and the distance that you expect to encounter them at.

A 175 Grain 7.62 x 51 mm might be quite capable of taking out the most dangerous game in the world at 1000 yards with a single properly placed shot, but I might feel a little under armed with the same rifle/cartridge combo if I was experiencing a little White Teddy Bear Charge at 25 Yards. There are rifle/cartridge combo requirements prior to hunting the Big Five, I'd consider these as "Knockdown Power" prerequisites. Now there have been hunters that have dropped elephants with lesser rifle/cartridge combos than you have listed. But the Old joke is: You know what the dark sticky stuff between an Elephants toes is? (Slow natives with under powered rifles.) So the size and tenaciousness of the game animal vice the distance you have before being mauled has allot to do with what the requirements are for knockdown power. JMHO. Do I need to expound on this?

 

[CptnAwesome]

The game animal we always discuss is southern whitetail. I knew this would get some good responses!

 

[Good Ol' Boy]

I haven't read all the replies.

All I will say is that when shooting at my AR500 1/4" thick gong at home a 22 barely moves it. A 9mm moves it quite a bit more and a 45 even more. A 223 moves it even more than that and a 308 rocks it.

Point being, certain rounds seem to have more energy whether by velocity or sheer mass, or a combination of the two.

If you want to refer to that as "knock down power" when talking about an animal or human then more "power" to you.