Which is more important in ballistics?

[IMTHDUKE]

In a defensive rd for a handgun which is more important to consider....muzzle velocity or muzzle energy?

 

[481]

Momentum at impact (mass times impact velocity) and what the bullet hits. So...velocity.

 

[Doc3402]

If you mean the ratings on the box of ammo, neither one. Too many things can affect the actual MV and ME. Barrel length and handgun condition are the two most obvious.

481 makes a very good point, but I think it's slightly misstated. Energy at impact is what I think he meant. Cross-sectional design is also important. More energy will be transmitted to the target if you use a flat nosed bullet than if you use something pointy.

Since you did state handgun in your post I think it's important to understand that shot placement is probably your most important consideration. For all intents and purposes hydrostatic shock is not a factor in most handgun calibers. The velocities are too slow.

 

[481]

481 makes a very good point, but I think it's slightly misstated. Energy at impact is what I think he meant.

Nope, I meant momentum.

Newton's laws of motion dictates how a bullet will behave as it penetrates soft tissue. The forces acting on the bullet arise from a decrease in momentum brought about by a change in its velocity (deceleration, in this case) are expressed as F = ma, so momentum is indeed what I meant.

 

[Rexster]

If it can make a hole, reliably, deep into the important bits, that is what is most important.

Velocity IS a component of energy. Muzzle velocity IS a component of muzzle energy. If all else stays the same, as velocity goes up, so does energy.

 

[481]

Velocity is also a component of momentum, hence p = mv. Penetration is a direct function of momentum and the best way to look at events of this type.

 

[Zak Smith]

Check the FBI protocol for testing terminal ballistics. It uses neither.

 

[btg3]

Muzzle velocity IS a component of muzzle energy

^^^This.
Velocity is just velocity.
Energy includes mass and velocity -- making it more significant than velocity alone.

In a defensive rd for a handgun which is more important to consider...

The question is flawed. As noted by other posters, there are more significant factors to consider.

 

[1911Tuner]

Velocity...Energy...Momentum. All part of the equation, and all variable. Mass is the only constant. The British worked it out two and a half centuries ago. "Heavy ball/Light charge."

 

[scaatylobo]

Neither

In my not so humble opinion.

Its accuracy and YOUR ability to hit a small moving target with ANY caliber.

After that,my vote goes to ability to penetrate soft tissue to a depth of 10 or 12 inches.

 

[Kleanbore]

Neither. Given the same mass, energy is determined by velocity.

Energy, or work, is one of the several things that determine penetration. Penetration and diameter determine effectiveness, along with point and direction of impact.

There are people on the wonderful world wide web who contend that momentum is the determinant of penetration, usually in the context of archery. They could use a physics course. Momentum will define two things: recoil, and how fast the target with the bullet in it will move after impact. The latter is very insignificant.

Consider that braking distance of an automobile varies with the square of the velocity. Same thing.

 

[481]

There are people on the wonderful world wide web who contend that momentum is the determinant of penetration, usually in the context of archery. They could use a physics course.

Duncan MacPherson, an MIT educated Aerospace Engineer, seems to believe otherwise and argues below that momentum is a valid way to model terminal ballistic behavior to include penetration. His momentum-based model predicts penetration and I doubt that anyone could argue that he is in need of a physics course.

Excerpt from "Bullet Penetration" by Duncan MacPherson:

“. . . every now and then someone wants to analyze or think about a problem involving energy, and when they attempt to do this without really understanding energy or other thermodynamic concepts the result is unfortunate. One such problem is the analysis of any of the various aspects of terminal ballistics; some individuals with inadequate technical training and experience have unwisely and unproductively attempted to use energy concepts in the analysis of bullet impact and penetration in soft tissue. (Many others have simply assumed that energy is the dominant effect in Wound Trauma Incapacitation; this assumption is even more simplistic than the attempt to actually analyze the dynamics problem with energy relationships, and is no more successful).

Any attempt to derive the effect of bullet impact in tissue using energy relationships is ill advised and wrong because the problem cannot be analyzed that way and only someone without the requisite technical background would try. Many individuals who have not had technical training have nonetheless heard of Newton’s laws of motion, but most of them aren’t really familiar with these laws and would be surprised to learn Newton’s laws describe forces and momentum transfer, not energy relationships. The dynamic variable that is conserved in collisions is momentum; kinetic energy is not only not conserved in real collisions, but is transferred into thermal energy in a way that usually cannot be practically modeled. The energy in collisions can be traced, but usually only by solving the dynamics by other means and then determining the energy flow.

Understanding energy and how it relates to bullet terminal ballistics is useful even though energy is not a useful parameter in most small arms ballistics work.”

 

[2zulu1]

^^^^^^

 

[MachIVshooter]

Muzzle energy is the easiest/quickest way to compare the relative capability of cartridges, but it's certainly not the only thing to consider, and you have to keep it in the same ballpark (for example, a .223 from a rifle and a .44 mag from a handgun have similar energy, but very different wounding mechanisms).

KE does largely determine a cartridge's ability to do work, work being bullet expansion & penetration. But it's not universal; The weight and construction of the bullet have to be appropriately matched to the power to achieve the desired performance. You can push a 90 gr. bullet out of a 9mm to velocities that will rival the energy of moderate .357 mag loads, but that .357 will be using a 125, 140 or 158 gr. bullet that is designed to hold together and acheive penetration, whereas that 90 gr. .355" pill is meant for the 900-1,100 FPS velocities of a .380, and will literally blow up in the medium when driven to 1,600+ in a 9x19mm +P load. So even though both that 9mm 90 gr. load and .357 mag 158 gr. load will generate around 550 FPE, the .357 load will be far more effective.

My personal feeling for defensive handguns is that more energy is better up to the level of full house 10mm, but it should be achieved using mid to heavy weight bullets for the caliber. Heavy bullet loads will have lower energies than the lighter bullets in a given cartridge, but almost universally achieve deeper penetration. I'd rather have a 124 gr. 9x19mm load making 375 FPE than the aforementioned 90 gr. load at 550 FPE.

 

[R.W.Dale]

I'm gonna give the same answer as I dis on the other forum Whee you asked this

The only thing that matters is what you put a bullet hole in.

Velocity and energy don't stop bad guys or kill game in the field. Bullet holes on the otherhand do.


You need shot placement, penatration, reliability and then energy-expansion

 

[MachIVshooter]

The only thing that matters is what you put a bullet hole in.

That's kinda the whole point of considering energy and momentum. A perfectly placed shot that dos not achieve adequate penetration is no better than a poorly placed shot that gets through but misses the structure. And a big hole is better than a small hole. To achieve that adequate penetration and large hole, you need energy and momentum.

No one is arguing that shot placement isn't top priority, but it would be asinine to imply that a 3mm Kolibri can be as effective as a .45 ACP with a hole in the same place. Stopping an attacker isn't popping a balloon. Ballistics matter.

 

[R.W.Dale]

Its no less asinine to imply that massive amounts of energy or velocity (at handgun levels) in any way make up for inferior shot placement.

Folks watch slow motion gel tests of modern jhp's in service handguns and get this false impression that the human body cannot cope with what they're seeing in the gel. This is a false assumption bourne out by the fact that over 80% of handgun gunshot victims survive

 

[WardenWolf]

From what I've seen in ballistics tests on Brass Fetcher, velocity matters a lot more than bullet size or weight. For example, comparing 7.62x25 (a .31 caliber projectile) to 9mm (a .357 caliber projectile), both using Speer Gold Dot hollowpoints, the Tokarev round is noticeably more destructive, inducing greater hydrostatic shock that is also much more violent (it produces a VERY pronounced cyclonic effect). Note that the Tokarev round is moving around 1400 FPS, whereas the 9mm round is moving around 1200 FPS. Bullet weight was 115 grains versus 124 grains.

Another example of this is exhibited with .45 ACP ammo. The heavier 230-grain bullet was very unimpressive, exhibiting worse performance than the 9mm round. However, the 203-grain bullet, with its higher velocity, proved devastating, far more so than 9mm. Again, both bullets were Speer Gold Dots. Velocity once again shows itself to be the key factor.

Of course, velocity also translates directly to muzzle energy. Because of the way energy is calculated, a lighter bullet traveling at a higher velocity often carries more energy than a heavier bullet traveling slower. Comparing from 124 grains at 1200 FPS in 9mm to 115 grains at 1400 FPS in 7.62x25, you lose approximately 8% of your weight, but gain more than 28% velocity, making for a substantial increase in overall energy.

 

[MachIVshooter]

Its no less asinine to imply that massive amounts of energy or velocity (at handgun levels) in any way make up for inferior shot placement.

Are you just wanting to argue for the sake of arguing? I have to assume so, since I made it clear that:

No one is arguing that shot placement isn't top priority

inducing greater hydrostatic shock that is also much more violent

Hydrostatic shock is not a reliable wounding mechanism at handgun velocities. Bullets moving slower than ~2,000 FPS do damage by crushing and tearing tissue directly contacted by the bullet. Yes, there is often some peripheral damage done by the temporary cavity, but again, that is not a reliable component with handgun rounds. Unless you're a Michael Courtney deciple, in which case reality isn't relevant...........

 

[WardenWolf]

Well, it depends. The Tokarev's hydrostatic shock was actually cyclonic. It was twisting, not just expanding. That would cause a lot more damage with regards to tearing tissues apart.

 

[R.W.Dale]

Its my observation that handgun cartridges seem to fall into groups it tiers of similar effectiveness when loaded with top tier defense loads for each.

Sub service or "pocket" pistol calibers

32-380-38spl ect

Not terribly effective, IMO best used with the deepest penatration loads for each expansion severely hampers penatration


Service calibers

9-40-357sig-mag-45 ect

Can drive modern expanding ammo hard enough to provide adequate penatration.

Hunting calibers or magnums

44mag-hot colt-10mm-some357-ect

Can drive bullets too hard if careful selection isn't made. Doesn't seem to bring anything to the anti 2 legged defense role compared to service calibers.

Then IMO you have a fourth set of big bore calibers that retain a satisfactory level of effectiveness sans expansion starting with 44spl +


Within these tiers terminal performance is so similar that factors of accuracy, recoil, platform and capacity become the primary considerations. With a few cartridges like 38spl, 10mm, 357mag and even 45acp having the ability to bridge the gaps in between depending on the platform and exact loading

 

[btg3]

True or false... Selection of handgun caliber will make the greater difference as compared to selection of a particular self-defense load within a given cailber.

 

[Frank Ettin]

Been through this before, but let's do it again.

There are four ways in which shooting someone stops him:

1. psychological -- "I'm shot, it hurts, I don't want to get shot any more."
2. massive blood loss depriving the muscles and brain of oxygen and thus significantly impairing their ability to function
3. breaking major skeletal support structures
4. damaging the central nervous system.

Depending on someone just giving up because he's been shot is iffy. Probably most fights are stopped that way, but some aren't; and there are no guarantees.

Breaking major skeletal structures can quickly impair mobility. But if the assailant has a gun, he can still shoot. And it will take a reasonably powerful round to reliably penetrate and break a large bone, like the pelvis.

Hits to the central nervous system are sure and quick, but the CNS presents a small and uncertain target. And sometimes significant penetration will be needed to reach it.

The most common and sure physiological way in which shooting someone stops him is blood loss -- depriving the brain and muscles of oxygen and nutrients, thus impairing the ability of the brain and muscles to function. Blood loss is facilitated by (1) large holes causing tissue damage; (2) getting the holes in the right places to damage major blood vessels or blood bearing organs; and (3) adequate penetration to get those holes into the blood vessels and organs which are fairly deep in the body. The problem is that blood loss takes time. People have continued to fight effectively when gravely, even mortally, wounded. So things that can speed up blood loss, more holes, bigger holes, better placed holes, etc., help.

So as a rule of thumb --

• More holes are better than fewer holes.
• Larger holes are better than smaller holes.
• Holes in the right places are better than holes in the wrong places.
• Holes that are deep enough are better than holes that aren't.
• There are no magic bullets.

And sometimes a 9mm might not be enough because sometimes even a .357 Magnum isn't necessarily enough. LAPD Officer Stacy Lim was shot in the chest with a .357 Magnum and still ran down her attacker, returned fire, killed him, survived, and ultimately was able to return to duty.

 

[MachIVshooter]

True or false... Selection of handgun caliber will make the greater difference as compared to selection of a particular self-defense load within a given cailber.

That's not a question so easily answered. The absolute, top-dawg premium load in a .32 ACP is still not going to be as effective as a .44 Spl. cowboy load.

On the other hand, a good, modern JHP 9x19mm load will likely outperform a .45 ACP FMJ.

Best answer: Choose a capable cartridge, find a platform that suits your needs, choose a quality load that performs well, then practice, practice, practice.

My absolute minimum for a defensive round is 200 FPE with a good bullet, whether it's a .380 or a .32 H&R magnum. Anything less than that, you're either making too small a hole or not getting enough penetration (or both). Whenever possible, I carry 10mm. It's got the power to drive a heavy bullet deep and expand it wide in any 2-legged threat.

 

[MikePGS]

"Placement is power." Stephen A. Camp