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Foot Pounds of Energy/Velocity = "Stopping Power" ??

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31K views 52 replies 20 participants last post by  481  
#1 ·
In recently studying of ballistics between the different commonly used service calibers (9mm, .40, .45 ACP) I have yet to determine what merits more "stopping power" between these rounds.

Now, I know that "stopping power" is a loosely thrown around term. What I am talking about here is, what factor (velocity, FPE, bullet grain weight, ect) differentiates the transfer of energy, from the round into its target, between these cartridges?

Looking at the same load (Speer Gold Dot) lets compare Velocity/FPE.


9mm 124 +P: V(1220), FPE(410)
.40 S&W 180: V(1025), FPE(420)
.45 ACP 230: V(890), FPE(404)
.357 SIG 125: V(1350), FPE(506)

Looking at this data, it appears that the .357 SIG is the clear winner. But, traditionally .40 and .45 ACP are regarded as the "more powerful" calibers. Obviously, the .40 and .45 have a larger bullet, but is the larger bullet the deciding factor in energy transfer?

-556
 
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#2 · (Edited)
All these rounds are essentially equivalent in stopping power... that is, they all basically suck. Other factors (bullet type, shot placement, proficiency, etc) will have a far greater effect on the outcome than any difference between the calibers. A good 9mm JHP is better than a .357 SIG FMJ.

Muzzle energy is a decent indicator of potential effectiveness but don't get too hung up on it.
 
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#3 ·
cowboy1964 said:
All these rounds are essentially equivalent in stopping power. Other factors (bullet type, shot placement, proficiency, etc) will have a far greater effect on the outcome than any difference between the calibers. A good 9mm JHP is better than a .357 SIG FMJ.

Muzzle energy is a decent indicator of potential effectiveness but don't get too hung up on it.
Click to expand...
I agree, bullet design (FMJ vs. JHP) will increase energy transfer. What I'm trying to find out (IF ALL OTHER THINGS ARE EQUAL), what factor gives one round more energy transfer or "stopping power" than another round.
 
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#4 · (Edited)
This has been endlessly debated, the.22 caliber .223 works well also, taking the math out of it and applying common sense big deep holes would probably work best, a .45 caliber hole all the way through should be better than a .357/9mm hole. But there are a lot of dynamics that come into play like striking bone etc. For me, the big deep hole theory works.
 
C
#6 ·
Energy is a function of both bullet weight and velocity. In terms of energy transfer, what's equally important is bullet design (i.e. FMJ, JHP, etc.)

However, penetration depth and permanent cavity size are the most important factors when it comes to stopping humans, and many bullets with less "energy" ratings do better in these departments than those with higher ratings.


Also, I think many would disagree with your statement reagrding the .357 as being less powerful than .40 or .45
 
#8 ·
Captains1911 said:
Energy is a function of both bullet weight and velocity. In terms of energy transfer, what's equally important is bullet design (i.e. FMJ, JHP, etc.)

However, penetration depth and permanent cavity size are the most important factors when it comes to stopping humans, and many bullets with less "energy" ratings do better in these departments than those with higher ratings.


Also, I think many would disagree with your statement reagrding the .357 as being less powerful than .40 or .45
Click to expand...
The 357 sig is clearly more powerful than 40 and 45.
 
#9 ·
Captains1911 said:
Energy is a function of both bullet weight and velocity. In terms of energy transfer, what's equally important is bullet design (i.e. FMJ, JHP, etc.)

However, penetration depth and permanent cavity size are the most important factors when it comes to stopping humans, and many bullets with less "energy" ratings do better in these departments than those with higher ratings.


Also, I think many would disagree with your statement reagrding the .357 as being less powerful than .40 or .45
Click to expand...
Maybe I should rephrase. Going off the data, the 357. is the winner based off of velocity and FPE. But, .40 and .45 seem to be regarded as the more favorable calibers when it comes to energy transfer or "stopping power".

This thread is not meant to be a 9MM vs. 357 vs .40 vs .45 war. We've all seen those and are tired of those. Im looking for the deciding factor in energy transfer whether it be bullet weight, velocity, FPE.
 
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#11 · (Edited)
Terminal ballistics, wound trauma incapacitation, is more complex than looking at bullet kinetic energy charts; in fact, KE is not a function of determining WTI and is an incorrect premise.

Let's use this data from Double Tap Ammunition ballistic gel tests as an example;

Here are official gelatin results for all of the DoubleTap loads!
All of these tests were done using 10% ballistic gelatin provided by Vyse gelatin using all FBI protocols and 4 layers of denim and two layers of light cotton T-shirt in front of the gelatin.

DoubleTap 9mm+P
147gr. Gold Dot JHP @ 1125fps (413 ft/lbs) - 14.00" / .66"

DoubleTap .357 Sig
125gr Gold Dot JHP @ 1450fps (584 ft/lbs) - 14.5" / .66"

DoubleTap .40 S&W Penetration / expansion
180gr Gold Dot JHP @ 1100fps (443 ft/lbs) - 14.75" / .68"

DoubleTap 10mm
180gr Gold Dot JHP @ 1300fps (675 ft/lbs) - 15.25" / .96"

DoubleTap .45ACP
230gr Gold Dot JHP @ 1010fps (521 ft/lbs) - 15.25" / .95"
Click to expand...
In Double Tap's gel tests, the two best performing Gold Dot loads in terms of penetration and crush cavity size were the 10mm and .45auto. If one uses KE in determining bullet penetration and crush cavity size; then how can the 154 ft/lb disparity between these two bullets be explained when both bullets expand and penetrate equally?

According to a KE model, the .357SIG 125gr GD should penetrate deeper and have a larger size crush cavity than the .45auto 230gr GD, but it doesn't.

Here's a technical read from 481 that explains why using a momentum model is better than using KE in a test between a handloaded 10mm 180gr Golden Saber (614fpe) and factory .45auto 230gr Winchester PDX (404fps), both are in the same sectional density grouping;

While sectional density is part of the overall terminal performance picture, that quantity is "redefined" at/during expansion. Penetration depth is inversely proportional to the expanded cross-sectional area of the bullet and directly proportional to the velocity of the bullet at impact. The dimension of the frontal area of the expanded bullet induces drag (effectively behaving as a "brake" within the media) and when this dimension increases (expansion diameter) drag increases by the square of the difference in the expanded radius which is effectively πΔr2


Therefore, while the effect of the difference between the 10mm's and the .45's final expanded diameter might seem small, it isn't.

The sectional density for each respective round drops significantly and the one that expands proportionately less gains an advantage in its 'new' sectional density.

Numerically speaking, the 10mm's sectional density decreases from 0.16071 to 0.05278 (33% of its prior sectional density) and the sectional density of the .45 decreases from 0.16118 to 0.07105 (44% of its prior SD) allowing the .45 load to destroy 6.25% more soft tissue and penetrate 1.33 inches more than the 10mm despite the 10mm load's greater KE (+214 fpe/ +53% more than the .45).

This phenomena clearly demonstrates why a "momentum" model is a better means of quantifying hard terminal ballistic performance than an "energy" model.

10mm 180 gr. Remington Golden Sabre JHP
Impact velocity: 1243 fps/618fpe
Average recovered diameter: 0.698"

Vcav = 389.302 fps
Mw = 58.906 grams (2.078 ounces)
Xcm = 33.361 cm (13.134 inches)

.45ACP Winchester Bonded PDX1 230 gr. JHP
Impact velocity: 889 fps (404fpe)
Average recovered diameter: 0.680"

Vcav = 392.366 fps
Mw = 62.603 grams (2.208 ounces)
Xcm = 36.748 cm (14.468 inches)
Click to expand...
Bob :cowboy:
 
#12 · (Edited)
Energy by itself means little. It's a measure of doing work. A 357sig FMJ will do less work than a 9mm JHP, even though the 357sig produces more paper energy. Using good JHP in all, the diff between worst to first is 90ft#, that is about like getting hit w/ an add'l. 22lr bullet, just isn't going to matter.
energy transfer whether it be bullet weight, velocity, FPE.
Click to expand...
The bullet is the deciding factor. Without the ability to do the work, the energy numbers mean very little. A good JHP will do more work w/ the same energy vs a FMJ, unless bone is struck. SO given a choice of 9mmJHP vs 357sig FMJ, 9mm JHP all day.
 
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#13 · (Edited)
fredj338 said:
Energy by itself means little. It's a measure of doing work. A 357sig FMJ will do less work than a 9mm JHP, even though the 357sig produces more paper energy. Using good JHP in all, the diff between worst to first is 90ft#, that is about like getting hit w/ an add'l. 22lr bullet, just isn't going to matter.

The bullet is the deciding factor. Without the ability to do the work, the energy numbers mean very little. A good JHP will do more work w/ the same energy vs a FMJ, unless bone is struck. SO given a choice of 9mmJHP vs 357sig FMJ, 9mm JHP all day.
Click to expand...
Nevermind, I misread
 
P
#15 ·
Jeff82 said:
http://www.firearmstactical.com/briefs3.htm
Click to expand...
I am not sure I buy this: "When you shoot an attacker in the torso, the goal is to produce fatal hemorrhage by rupturing the heart or a major blood vessel so he will quickly collapse." The goal is to stop the attack. They give instance where the person becomes unconsious with a shot to the shoulder as a mind game. Maybe, but I think it is more complex than what you want is heart shot. About 80% of handgun wounds are survived.

As far as the fat guy and the 357 mag., you can find individual shooting where just about anything can happen. Almost seemed to be indicating the .22 would be better than the 357. The effect bullet transferred energy has in regard to stopping is not well defined. Notice, I said stopping an agression. That is the goal.
 
#16 · (Edited)
10mm 180 gr. Remington Golden Sabre JHP
Impact velocity: 1243 fps/618fpe
Average recovered diameter: 0.698"

Vcav = 389.302 fps
Mw = 58.906 grams (2.078 ounces)
Xcm = 33.361 cm (13.134 inches)

.45ACP Winchester Bonded PDX1 230 gr. JHP
Impact velocity: 889 fps (404fpe)
Average recovered diameter: 0.680"

Vcav = 392.366 fps
Mw = 62.603 grams (2.208 ounces)
Xcm = 36.748 cm (14.468 inches)

Anyone seriously think the difference between 10mm and 45ACP given the above is going to really affect the outcome of a shooting in any measurable way?

Momentum is great but using it in lieu of energy doesn't make sense either. The whole story is way more complicated than that.

I think it was Ayoob that pointed out that if energy is so irrelevant why is it that there is such a strong correlation between energy and effectiveness? (note: I said "strong", not
"perfect") Much more so than momentum. If you don't believe it calculate the momentum of a 230gr 900 fps .45 ACP vs a 3200 fps 55gr .223.
 
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#20 · (Edited)
cowboy1964 said:
Momentum is great but using it in lieu of energy doesn't make sense either. The whole story is way more complicated than that.
Click to expand...
Yes, way more complex than you let on.

That is why we consider not just momentum, but the total frontal area of the expanded round and the resultant cavitation regime threshold velocity of that dimension as well as its coefficient of drag, the retained mass of the recovered projectile, its velocity at impact and final depth of penetration.

Kinetic energy has far less correlation with terminal performance (permanent wound cavity mass, penetration depth) than does momentum.

After that, it is all about placement. (and what is actually hit)


Duncan MacPherson on the relationship of momentum and kinetic energy to terminal performance (taken from pages 6-8 of his book, "Bullet Penetration"):

“. . . 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.”
Click to expand...
 
#21 ·
PghJim said:
I am not sure I buy this: "When you shoot an attacker in the torso, the goal is to produce fatal hemorrhage by rupturing the heart or a major blood vessel so he will quickly collapse." The goal is to stop the attack. They give instance where the person becomes unconsious with a shot to the shoulder as a mind game. Maybe, but I think it is more complex than what you want is heart shot. About 80% of handgun wounds are survived.

As far as the fat guy and the 357 mag., you can find individual shooting where just about anything can happen. Almost seemed to be indicating the .22 would be better than the 357. The effect bullet transferred energy has in regard to stopping is not well defined. Notice, I said stopping an agression. That is the goal.
Click to expand...
The best way to stop the attack is to get either a CNS hit or cause unconsciousness via blood loss from injured organs. We can't rely on the "psychological stop" as we have no control as to when it will or will not appear. Any round used must penetrate far enough to get to the vitals and at that point bigger is better as there is more wounding surface to the bullet.

So the two factors you are looking for are penetration and permanent wound tract size. Temporary stretch is not a factor at handgun velocities. These two factors are unimportant if shot placement isn't good. Nothing else really matters.
 
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#22 · (Edited)
Jeff82 said:
The best way to stop the attack is to get either a CNS hit or cause unconsciousness via blood loss from injured organs. We can't rely on the "psychological stop" as we have no control as to when it will or will not appear. Any round used must penetrate far enough to get to the vitals and at that point bigger is better as there is more wounding surface to the bullet.

So the two factors you are looking for are penetration and permanent wound tract size. Temporary stretch is not a factor at handgun velocities. These two factors are unimportant if shot placement isn't good. Nothing else really matters.
Click to expand...
Quoted because everyone should be required to read Jeff's post at least twice before posting anything in "Caliber Corner". :winkie:
 
#23 ·
Jeff82 said:
The best way to stop the attack is to get either a CNS hit or cause unconsciousness via blood loss from injured organs. We can't rely on the "psychological stop" as we have no control as to when it will or will not appear. Any round used must penetrate far enough to get to the vitals and at that point bigger is better as there is more wounding surface to the bullet.

So the two factors you are looking for are penetration and permanent wound tract size. Temporary stretch is not a factor at handgun velocities. These two factors are unimportant if shot placement isn't good. Nothing else really matters.
Click to expand...
+1 :cheers:

Time to kick back, crank up the volume on some Mo-town tunes, get a cold one out of the fridge and read your post again! :bluesbrothers:

Bob :cowboy:
 
P
#24 · (Edited)
Jeff82 said:
The best way to stop the attack is to get either a CNS hit or cause unconsciousness via blood loss from injured organs. We can't rely on the "psychological stop" as we have no control as to when it will or will not appear. Any round used must penetrate far enough to get to the vitals and at that point bigger is better as there is more wounding surface to the bullet.

So the two factors you are looking for are penetration and permanent wound tract size. Temporary stretch is not a factor at handgun velocities. These two factors are unimportant if shot placement isn't good. Nothing else really matters.
Click to expand...

I do not think anyone doubts that. However, if your chances of a CNS hit or blood loss are the same with either bullet, I would take the one with the higher energy. I do not think I mentioned Temporary Stretch. In my hunting experience, I see more damage with a high energy load. I have shot rabbits with a 357 hard cast bullets moving at 38 special speed and the same bullet moving at 357 magnum speed. Both completely penetrate the animal but the faster bullet does more damage. I only use this as one example.

Why is it that when one advocates a higher energy bullet, people think they are making up for shot placement? I also believe there are other shots that would stop an attack such as a broken pelvic bone, hip, sturctural leg bone, collapsed lungs, etc. The link goes into great length to tell where the 22 bullet went, but does not give a good description as to the paths of the 357 bullets on the fat man. I would not really consider those Silver Tip bullets to be high energy, though much higher than the 22. If the man was shot four times in the center on the chest with the 357 then I would really listen.
 
D
#25 · (Edited)
PghJim said:
I do not think anyone doubts that. However, if your chances of a CNS hit or blood loss are the same with either bullet, I would take the one with the higher energy. I do not think I mentioned Temporary Stretch. In my hunting experience, I see more damage with a high energy load. I have shot rabbits with a 357 hard cast bullets moving at 38 special speed and the same bullet moving at 357 magnum speed. Both completely penetrate the animal but the faster bullet does more damage. I only use this as one example.

Why is it that when one advocates a higher energy bullet, people think they are making up for shot placement? I also believe there are other shots that would stop an attack such as a broken pelvic bone, hip, sturctural leg bone, collapsed lungs, etc. The link goes into great length to tell where the 22 bullet went, but does not give a good description as to the paths of the 357 bullets on the fat man. I would not really consider those Silver Tip bullets to be high energy, though much higher than the 22. If the man was shot four times in the center on the chest with the 357 then I would really listen.
Click to expand...
If the man was shot four times in the center on the chest with the 357 then I would really listen.
Click to expand...
Why? The topic of discussion is high energy impacts. All else equal, chest or belly, the energy absorbed would be the same. The only difference being that the same shots to the chest would have a greater percentage of hitting the vitals. This brings us back to placement and penetration. Trooper Coates was killed due to proper placement and penetration (however lucky/unlucky the shot was), not energy.
 
#26 ·
BTW, WTH is "Vcav"? I was assuming it was cavity volume but why is the units "fps"? Cavity velocity??? Huh?

10mm 180 gr. Remington Golden Sabre JHP
Impact velocity: 1243 fps/618fpe
Average recovered diameter: 0.698"

Vcav = 389.302 fps
Mw = 58.906 grams (2.078 ounces)
Xcm = 33.361 cm (13.134 inches)

.45ACP Winchester Bonded PDX1 230 gr. JHP
Impact velocity: 889 fps (404fpe)
Average recovered diameter: 0.680"

Vcav = 392.366 fps
Mw = 62.603 grams (2.208 ounces)
Xcm = 36.748 cm (14.468 inches)
 
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