Does velocity matter?

[JohnKSa]

I thought the temporary stretch cavity in a handgun round was really irrelevant.

The best way to understand this is to think of examples of both wound channels and temporary cavities that don't involve bullets and then relate them back to terminal performance.

A slash or stab from a very sharp thin-bladed knife creates a wound channel without creating any significant temporary cavity. You could bleed to death as a result of the cut or it might disrupt an important organ enough to cause death. It's pretty reliable--a deep cut or slash is probably going to result in a very serious injury and significant bleeding no matter where it happens.

A baseball bat strike creates a temporary cavity without a wound channel. Taking a hit on a large muscle or a very fatty part of your anatomy might result in nothing other than some pain and bruising. But in certain circumstances--perhaps a strike to your liver area--it could cause a lethal injury due to internal bleeding. It's not very reliable--it could cause anything from pain and bruising to a fatal injury. But it's not irrelevant by any means.

 

[biohazurd]

I got my .45 running under 1000 fps just like everyone else, and i dont see anyone in a line to get shot by it. However with a smaller projectile like a 9mm velocity is key to its effectiveness, as well as a JHP

 

[Nnobby45]

I thought the temporary stretch cavity in a handgun round was really irrelevant.

Not exactly. The higher the velocity, the more of a factor velocity becomes.

It's already been pointed out that the stretch cavity can't always be relied on in pistol ammo, but in some calibers it's significant.

What did the .357 Mag. have going for it.?

125 gr JHP for optimum velocity higher than most pistol rds.

A bullet that tended to shed it's jacket

A stretch cavity greater than most pistol rds.

The ability to stop fights better than anything (commonly carried).

Still, we have opinions today that denounce the value of the stretch cavity, shun bullets that shed their jackets, and claim that velocity isn't really an issue.

 

[tipoc]

Velocity matters because energy matters.

Bullet construction also matters though. The well constructed bullet from a 9mm or a 40S&W or a 45acp will all penetrate barriers as well as any .357 Sig round or .357 Magnum.

There is marketing hype that the .357 Sig penetrates better than many other rounds. It does not. It is also a myth that the ,357 Magnum with a 125 gr. bullet is the hands down best "stopper". No evidence to prove that.

If you look at the brass fletcher, the box o truth and other sites and books, etc. you can learn a good deal about what penetrates and expands best and how. Bullet construction and type, plays more of a role than many like to think or are aware of I think.

tipoc

 

[Braintrain]

yes, it does

 

[ClydeFrog]

Speed's fine but accuracy's final...

Speed or vel is related to the size/wt of the projectile or expanding bullet.
100 or 200 fps(ft per second) may not be that big an issue but if you compared a pistol round vel of 900 fps to 1200 fps, like a .45acp & a .357sig, then it would mean more.

I read a long time ago that US Army R&D found that any projectile going faster than 300 fps could be lethal.
In duty/protection handgun rounds, I think most smart procurement or ordanance officers/staff choose loads that can go 12-14" in test mediums, travel about 1200fps(9mm-.40-.357sig), and retain 100% of the wt(or close to it).

Rounds like the Speer Gold Dot, Corbon DPX, Remington Golden Saber, and Winchester Ranger T sell so much in the US for these reasons.

 

[LordTio3]

THANK YOU JOHNKSa!!!

This is nearly the exact same example I use to explain the ridiculous idea of "Stopping Power" as many people understand it. A gunshot wound consists of two things: a temporary wound cavity, and a permanent wound cavity.
You can also think of them as the "felt physical impact" and "actual tissue destroyed/displaced" respectively.

I use the exact same examples of being hit with something heavy to simulate "felt physical impact" and a singular puncture wound from being stabbed to simulate the permanent wound cavity of actual destroyed tissue.

You aren't going to be knocked down by a bullet. It just won't happen. Unless it's fired from something other than a person; ship/platform/turret. Physics tells us that for every force/action there is an equal and oposite force/action (Newton's 3rd). If a round had the ability to knock down a person, the shooter would be knocked down as well. So we know that the temporary wound cavity or FPI has very limited potential to wound as it is being fired from the hands of another person and is thus limited in it's potential, but it is not in any way irrelevant. Do not underestimate the power of hitting someone with a heavy object in a fight. It causes physical/psychological shock, can "knock the wind" out of someone, can re-direct a charging attacker, or cause enough internal "trauma" (not damage) to disrupt one or several bodily processes (respiration in particular).
However, this makes your true stopper penetration or ATD. And for this, velocity is your very best friend.

We all know that handgun calibers are under-powered. So any velocity you can get is your friend. It will help expanding ammunition expand sooner, creating a more fierce FPI while still providing adequate penetration, if not greater penetration, to cause enough damage DEEP ENOUGH to stop stop major processes (respiration, circulation, nerve conduction) to end the encounter.

Personally, I'll take all the velocity I can get out of my handgun.

~LT

 

[LordTio3]

Speed or vel is related to the size/wt of the projectile or expanding bullet.
100 or 200 fps(ft per second) may not be that big an issue but if you compared a pistol round vel of 900 fps to 1200 fps, like a .45acp & a .357sig, then it would mean more.

What you are refering to here is the difference between Velocity and Force. Velocity is simply acceleration in a given direction. When you add mass of the object/projectile, you are speaking about Force; and in this you are exactly right. The heavier the object, the bigger difference velocity makes.

I read a long time ago that US Army R&D found that any projectile going faster than 300 fps could be lethal.

The average person sneezes residue out at around 293ft/s. These projectiles aren't in any way shape or form lethal. However, this just serves to reinforce your previous point about Force provided the relativity of the projectiles mass to the equation. Sinewy snot isn't exactly a 124grain bullet.

Bottom line, velocity wins. More = better, generally when using handguns. And it does make a difference.

~LT

 

[ClydeFrog]

germ warfare...

Now come on LT, I highly doubt the US Army or DoD would weaponize human cold germs, but don't give them any ideas!

Really I agree force is made by size/mass but to me, higher vel helps push a expanded bullet/projectile deeper.

 

[Webleymkv]

I think many may have velocity confused with energy. It is true that high-velocity rounds tend to have the most energy, but this is not a universal truth. Because the formula for energy is mass times velocity squared, a change in velocity will have a much greater impact on energy than a change in mass would. However, given a light enough projectile, it is possible to have a very high velocity projectile that still has relatively little energy. For example, Buffalo Bore's heaviest .44 Magnum loading has roughly the same energy as a 55grn .223 round from a 20" rifle barrel. While the .223 has roughly twice the velocity of the .44 Magnum, the .44 is nearly seven times heavier.

It is actually energy and how it is transferred to the target that causes temporary cavitation and its associated effects, high velocity is just the most efficient means to achieve high energy.

 

[TailGator]

Excellent explanation and analogy by John KSa.

With my apologies to those who have had to endure a similar post from me in the past, an aspect of ballistic gel that should be considered is that it is intended to simulate the body tissues that are composed primarily of water. When we shoot at the chest, we are shooting at a water-density organ (heart and great vessels) surrounded by two air-filled organs. Lungs in life have a consistency similar to flexible packing foam. Since the air component of living lung tissue is far more easily compressed than is water, it absorbs and cushions the pressure waves resulting from a bullet impact; for the same reason, diagnostic ultrasound is of very limited value in examining lung tissue and cardiac ultrasounds are done through a small window where the heart is in contact with the body wall. The result of that cushioning in ballistics is that lung tissue suffers far less damage radiating out from the actual path of the bullet than does fluid-density tissue.

Fat, too, is much more deformable than fluid-dense tissues, and therefore dampens the effects of bullets (and does not ultrasound well).

For similar reasons, I would not expect JHPs to expand nearly as well in lung tissue as in fluid-dense tissue. I am not aware of any studies specifically addressing this issue; however, I would expect them to maintain velocity to a greater extent and expand to a lesser extent due to the difference in tissue density. Neither would I expect the lung tissue to transmit damaging force to the heart in any but the closest of "near misses."

Blood loss from lung shots, unless a large vessel is directly hit, can be expected to be much less significant than that resulting from a shot to the heart with the same ammo, and the probability of immediate incapacitation is considerably lessened, as is the risk of mortality.

 

[LordTio3]

Really I agree force is made by size/mass but to me, higher vel helps push a expanded bullet/projectile deeper.

I agree wholeheartedly.

@Webley- Yes Energy is another moniker often interchangeably used with force when discussing physics, and you are dead on with your assessment of it's ballistic implications between calibers.

@TailGator- Nice.

~LT

 

[Nnobby45]

Velocity increases the ability of a bullet do do it's job. The bullet, of course, must be constructed to match the velocity so that optimum expansion and penetration can be achieved. Match extra velocity with the wrong bullet, and much of it's potential is wasted.

The higher the velocity, the wider the parameters in which a properly designed bullet can operate.

 

[DBAR]

It is actually energy and how it is transferred to the target that causes temporary cavitation and its associated effects, high velocity is just the most efficient means to achieve high energy.

I agree....

If the velocity of a 125-grain projectile is 1400 fps, then it's going to drop more energy on the target than the same projectile traveling at 1200 fps. It's a simple fact that cannot be denied. So is the fact that I wouldn't want to get hit by either of them.

With that said, I really like the 357 Sig round, and I think that it's worthy of anyone’s consideration. It works, and it does what it was designed to do.

If you really don't believe that velocity matters, then you should do some research on the subject. I'm just saying....


DBAR

 

[briandg]

a gun is a kinetic energy projectile weapon. Its purpose is to make a hole in a target and make it bleed. The bigger the hole, the more chances you have of tearing capillaries and increasing bleeding. Deep, wide, both count. The temporary cavity counts too, as you will still tear capillaries and tissues just by pulling.

A bullet on the end of an arrow is not a lethal projectile. A hollow point at 1,500 fps is. The faster they go, the better they work, unless you are using the wrong bullet.

You could load a 125 grain bonded bullet into a .35 Whelen, push it past 3,000 fps, and your wound would be catastrophic.

Every bit of energy/velocity you add gives a greater POTENTIAL for a killing/disabling wound. But, there are no guarantees, and something as simple as a rib can mess up all of the nice neat equations.

 

[Cosmik de Bris]

Speed or vel is related to the size/wt of the projectile or expanding bullet.
100 or 200 fps(ft per second) may not be that big an issue but if you compared a pistol round vel of 900 fps to 1200 fps, like a .45acp & a .357sig, then it would mean more.
What you are refering to here is the difference between Velocity and Force. Velocity is simply acceleration in a given direction. When you add mass of the object/projectile, you are speaking about Force; and in this you are exactly right. The heavier the object, the bigger difference velocity makes.

You seem quite confused about the terms you are using. Velocity is not acceleration in a given direction, velocity is speed in a given direction. Acceleration is the rate of change of velocity.

When you combine velocity and mass you get momentum or energy depending on how you combine them. Force is the rate of change of momentum, or mass times acceleration.

Cheers

 

[WESHOOT2]

insertion

Bullets used in the 357 SIG cartridge are specific to the cartridge.

Yes, velocity matters. On humans......



FWIW, myths are always based on fact: The 357 SIG displays unusual prowess at penetration; the 357 Anything (or 9mm Anything) high-speed 124/125g JHP is the most effective stopper; the internet is not normally noted for its veracity.

 

[LordTio3]

Velocity:
2. In physics, velocity is the rate of change of position. It is a vector physical quantity; both magnitude and direction are required to define it.

Rate of Change/time = acceleration
Thus,
Velocity = acceleration with respect to a defined vector or direction.

Secondly, you can use Momentum in this instance, but you shouldn't because it is too specific of a measure in an incredibly variable system.

While I do realize that Google lists "Momentum = mass X velocity" or "p=mv", when you actually study physics, you realize that this isn't all there is to the equation. There is a reason that you never hear the term "momentum" when refering to ballistics calculations. It just does not fit.

Thus the rate of transfer of momentum, i.e., the number of kg·m/s absorbed per second, is simply the external force.

In physics, the term Force simply describes any physical influence which can impose a change of velocity on a material; which pertains to both the time the bullet is accelerating in the barrel and decelerating in human tissue (i.e. the force exerted on the projectile by the concentrated chemical reaction, and the potential force exerted on the tissue by the projectile.)

Without defining the Lorentz Factor or distinguishing between the two any further, momentum does not fit very well in this example as the frame provides too much variance to utilize a closed-system measurement like momentum. Therefore the general moniker Force is much more applicaple to speaking of transfer of energy from one object in flight to another of greater mass at rest.

Please... don't argue about physics if Googling or 10th grade are your only reference for it. And let's not make a point to simply attempt to correct each other beyond a simple clarification without offering anything else to the discussion.

Every bit of energy/velocity you add gives a greater POTENTIAL for a killing/disabling wound. But, there are no guarantees, and something as simple as a rib can mess up all of the nice neat equations.

This is exactly the right way to think about projectile velocity and "Potential Effectiveness". Adding any bit of velocity really does help this cause, and I will take every bit I can get. .357 Sig is a very hot load when using the correct materials. And if you have any questions about it's effectiveness...

...ask the Secret Service about it.


~LT

 

[ScottRiqui]

Velocity is simply acceleration in a given direction

LT,

Maybe this isn't what you meant to say, but it's dead wrong and Cosmik was right to correct you.

And p=mv is a fine expression for momentum when talking about bullets. There's no need to bring the Lorentz factor into the discussion, because we're talking about decidedly non-relativistic situations here. At the masses and speeds we're dealing with, the Lorentz factor is so close to 1 that even if you use the full "correct" relativistic equations, they all collapse to the classic Newtonian equations anyway - at least to one part in a hundred billion or so.

 

[LordTio3]

Maybe this isn't what you meant to say, but it's dead wrong and Cosmik was right to correct you.

You're right. The way that sounds I did mean for. I do not mean to use Acceleration as a definitional sense as much as a verb in this sense and perhaps that is what is causing the confusion. I speak of an objects velocity, in this example a bullet, as being the end result of it's 'having been accelerated with reference to a particular vector'; which in hindsight was rather misleading after this phrase...

Velocity = acceleration with respect to a defined vector or direction.

... being in the literal definitive tense, which should have read

Velocity = result of acceleration with respect to a defined vector or direction.

And as I re-read more carefully, Cosmik ends his correction and just goes on to define momentum, which is a fine measurement when dealing with colliding objects, just not the one I would tend to use in this sense- which is why I attempted to mention the Lorentz Factor with intended satirical overtones as my own way of mentioning, before things got out of hand, that we should, "keep it simple"; which is a jest I'm sure you'll understand.

After re-reading I appologize to Cosmik. Didn't mean to "fly-off-the-handle" about physics; just spent all day yesterday arguing Newton and Euclid, and I guess I'm still in debate mode.

Back to Briandg:

Every bit of energy/velocity you add gives a greater POTENTIAL for a killing/disabling wound. But, there are no guarantees, and something as simple as a rib can mess up all of the nice neat equations.

Not only do you worry about getting through ribs, but think about layered clothing, hard bone, jackets from leather to down, denim, pacemakers, midieval chestplates, etc... THEN if they happen to get a limb between themselves and the round, you have an extra 2-6 inches of flesh to get through, probably another large bone, plus jacket/shirt/pant material on both sides and space between the limb and torso before you even start in towards the vitals.

In conclusion, velocity and penetration depth are very important, if not THE MOST important factors regarding handgun ammunition. You need to be able to get to the vitals to stop an encounter, unless you happen to hit CNS. Either will do the trick... but the torso is much larger and moves around a lot less. And it's usually not shrouded by a piece of steel firing bullets back at you like the head is.

~LT