Stopping Power - Knock Down Power

[Ziggy2525]

Momentum vs KE

Quick analogy first. When they evaluate a football player for the pros, they measure their 40 yard sprint time, vertical jump, bench press, etc. One player, but different measures to evaluate potential success.

Similarly, Momentum and Kinetic Energy are two measures of the same bullet performance to evaluate potential success.

Momentum is how much wallop the bullet has. All other things being equal (they never are), a bullet with more momentum will hit harder and penetrate deeper than the same bullet with less momentum. The deeper the penetration in living things, the more likely to hit vital organs. The harder the wallop, the more likely to knock something down. Since all things aren't equal and are hard to calculate, they do gel tests to compare penetration.

Kinetic Energy doesn't do anything by its self. When a bullet hits something the KE gets converted into other forms of energy as the bullet travels along the wound track. In a living thing, pretty sure that's heat and a pressure pulse that moves the surrounding tissue. The more Kinetic Energy a bullet has, the more damage along the wound track from the converted heat and pressure pulse. Except.. even though service caliber pistol rounds have KE and create heat/pressure along the wound track, from what I've read, the amount isn't enough to damage the tissue around the wound track like it would with a high power rifle round.

IMO,
The concept of Knockdown Power is sort of related to momentum.

The concept of Physical Stopping Power (as opposed to psychological stopping power) is more related to KE. So much damage was done along the wound track, the person goes into immediate shock.

I don't think normal pistol rounds have enough Momentum or KE to have either.

 

[Ribwizzard]

Not really. it is a measure of bullet momentum & dwell time on the target. All the service rounds have about the same ME, +/- 50ft#. Depending on the bullet though, momentum, is vastly diff. So no, doesn't tell you anything really about a bullets ability to stop a man.
Its about the bullet & what it does to the target. A 9mm jhp w/ slightly less ME than a 45 solid, I am taking the 9mm jhp all day because it will crush more tissue & do more damage to the target. Yet the 45 will knock still over with more authority,


????????not really what,,?,??????????
Your comments do not relate to my statement in any way, did you even read it?

 

[fredj338]

It's simple, forget about human targets. Line up a dozen empty scuba tanks and shoot them from 7 yards with .22, .380, 9m, .45, 357, .44 mag, .50.
You will see that some will knock down the tank and some will not. That is real and measurable performance of knock down power.
Do the same using ballistic gelatin, that is real measurable performance for potential stopping power.
It doesn't matter if it will always stop a man, but it is still measurable and real.
Two ton jack wont lift 10 tons, but doesn't mean it doesn't have two tons lifting power.

Yeah did read it, maybe you forgot what you wrote, my comment still applies & is correct. Shooting metal targets doesn't relate to shooting large animate targets. I am pretty sure you are not understanding terminal ballistics at all. You fall into the trap that many do by shooting inanimate objects & trying to correlate their affect on living targets. Even ballistic gel is not a living target. it is homogenous, no bones, it only give an idea what the bullet might do, but it is not definitive.

 

[Ribwizzard]

Yeah did read it, maybe you forgot what you wrote, my comment still applies & is correct. Shooting metal targets doesn't relate to shooting large animate targets. I am pretty sure you are not understanding terminal ballistics at all. You fall into the trap that many do by shooting inanimate objects & trying to correlate their affect on living targets. Even ballistic gel is not a living target. it is homogenous, no bones, it only give an idea what the bullet might do, but it is not definitive.

Becouse that is how you measure the potential. You have to set a base line= identical targets. Especially a hard , heavy target that will deflect the energy the least.
How can you possibly get consistent results shooting live tissue? It's just like you said. One time you hit bone, next time you dont.
Your comment is irrelevant and your next is insulting, keep it up and I will report. This should be a fun , interesting topic, not a argument like those above keep trying to turn it into. I do not have the time or desire to make sure everyone of my posts is troll proof, so If arguing is your game, please take it elsewhere. If having an intellectual , mature, conversation about measuring the potential energy of different cartridges, then I welcome you to continue.

 

[Ribwizzard]

Now, moving forward, all I care about is measuring knock down power. The ability of one caliber to knock down an object over another.
I dont care about penetration, I want none.
I dont care about deformation, I want none.
I want my projectile to transfer its energy into the target in the fastest most efficient way possible. Becouse all I want to measure is its ability to knock a particular target over.I.E. = KNOCK DOWN POWER

 

[Gamecock]

I love Larry Potterfield's fist pump when describing "knock down power."

[ame]https://www.youtube.com/watch?v=7KQrfhQcaLA[/ame]

 

[Kanewpadle]

Time to lock this thread. It’s getting way too complicated.

 

[shouldazagged]

I agree. Good night, all.

 

[fredj338]

Now, moving forward, all I care about is measuring knock down power. The ability of one caliber to knock down an object over another.
I dont care about penetration, I want none.
I dont care about deformation, I want none.
I want my projectile to transfer its energy into the target in the fastest most efficient way possible. Becouse all I want to measure is its ability to knock a particular target over.I.E. = KNOCK DOWN POWER

Except little energy is transfered to the target. How much of the say 400ft# of muzzle energy from a service rd is transfered to any solid target? How is 400ft# delivered by a 90gr 9mm at high vel not transmitting that to steel target like a slow 230gr 45, same ME.. Most of the ME of a bullet hitting the target is used up deforming the bullet. Why this mythical knockdown power cant really be measured or quantified.
Btw, You can run & cry foul if your feelings are hurt, but that is on you. Pretty sure this is not a safe zone like college??? Put out questionable statements, its gonna get questioned??

 

[Kanewpadle]

Gentlemen, I asked for another term we could use instead of stopping power or knock down power. Not a lesson on what you think it means. The preaching and posturing is really getting old.

Mods, please lock this thread. Thanks.

 

[Ribwizzard]

Except little energy is transfered to the target. How much of the say 400ft# of muzzle energy from a service rd is transfered to any solid target? How is 400ft# delivered by a 90gr 9mm at high vel not transmitting that to steel target like a slow 230gr 45, same ME.. Most of the ME of a bullet hitting the target is used up deforming the bullet. Why this mythical knockdown power cant really be measured or quantified.
Btw, You can run & cry foul if your feelings are hurt, but that is on you. Pretty sure this is not a safe zone like college??? Put out questionable statements, its gonna get questioned??

It's just getting ridiculous with these responses. If I set up a test bench with identical targets and similar projectiles , but in different caliber, I can clearly see the different effects each have on the target. This is not mythical. Anyone with any experience shooting other than paper targets should know this. Give it up already. Your .380 does not send a bowling pin flying as well as a .45acp becouse of obvious reasons.

To the rest, my point is :
Stopping power is very debatable, with so many variables as shot placement, bullet expansion, density of target (clothing, armor) etc. To many variables.
BUT, knock down power is real and measurable by ways mentioned above. And we can use that value, along with other values we test, like penetration, bullet expansion, etc. And then we can create a formula that would give us the "POTENTIAL " stopping power of each caliber per "X" kind of target.

Nothing mythical about it. If you set the proper benchmarks for each kind of test, each is very much measurable. And of course, the formula wont be perfect, but would give us a guideline of what each caliber potential would be with each kind of target.

I think it would be a fun project to put together we could all work on as a group, at least I did before the attack of the trolls just completely wore me out on the subject. Seriously, Its comparable to asking the difference between horsepower and torque at the local bar at 2am.

 

[forrestinmathews]

From another angle: When staying at a hotel, I am concerned about innocents that may be staying in rooms across the hall or around me. I think I would rather be killed myself than to kill a child.

What say you about that?

If you don't like this line of thinking, just remember; I am a frog. What do we know?

Are you a quiet and professional sort of frog? You must be really bored then to hang out here. Usually frogs hang out with other frogs and tell frog stories in ribbits to confuse other creatures.

 

[forrestinmathews]

Gentlemen, I asked for another term we could use instead of stopping power or knock down power. Not a lesson on what you think it means. The preaching and posturing is really getting old.

Mods, please lock this thread. Thanks.

You had to have a reasonable expectation that this.would open a can of worms and that all the usual suspects would emerge to do battle in epic fashion each feeling smarter than before and pontificating better than ever to finally lay this matter to rest.

I submit that we use the term Ballistic Usage Resolution Potential or BURP. It would cleanly cover the subjective and objective angles.
For example: Is your BURP greater than my BURP? It is difficult to say, however your BURP has sound, smell and penetration qualities which I find less than ideal...
Or...
Your BURP while lacking the powerful qualities of my BURP might still be sufficient in most situations. I'm certain that your BURP would be more comfortable to carry around in social settings and easier to use without drawing unwanted attention and criticism...

 

[Gamecock]

If you insist, Kanewpadle.

If the only sure stopper is a supersonic telephone pole, each caliber could be rated in SSTP units.

E.g., a .45 ACP would be rated .08 SSTP.

But I'm a bit skeptical of your complaint. You declared something non-existent, then asked for a name for it. The responses are therefore appropriate.

It’s been stated everywhere that there is no such thing as Stopping Power or Knock Down Power.

So that being the case, what DO you call it?

 

[Kanewpadle]

If you insist, Kanewpadle.

If the only sure stopper is a supersonic telephone pole, each caliber could be rated in SSTP units.

E.g., a .45 ACP would be rated .08 SSTP.

But I'm a bit skeptical of your complaint. You declared something non-existent, then asked for a name for it. The responses are therefore appropriate.

I did not declare anything non-existent. It’s a well known fact that stopping power is considered a myth. Some of the responses are nothing more than conjecture.