Stopping power - expansion vs ft/lbs, velocity

[weeple2000]

Reading Ingot to Target and learning about casting has me wondering about the relationship between stopping power, velocity, and expansion. I recently picked up a chronograph which has my curiosity piqued. Here are chronograph results of 4 loads. There are 3 bullet varieties. I shot these out of a snub nose revolver. I believe that trail boss load was 3.18 grains. The 3 bullets are:

Factory Winchester PDX1 Defender 38 special +P 130 Grain Bonded Jacketed Hollow Point
Speer Swaged LSWCHP
Lee TL358-148-WC cast with range lead, I think these dropped about 152 grains.

I used trail boss to load the Speers before I had the data for the bullet. So I just err'd on the side of caution. I have 2 examples for the DEWC with different charge weights. I want to bump that up to 3.2 grains of Red Dot to see how many more fps I can squeeze out of it. My Lyman #4 cast handbook lists 3.3 or 3.2 for their two DEWC's that are in that weight range.

I want to shoot these four examples into a phone book or wet newspaper to see how they expand. Winchester listed 946 as the velocity for 5 yard for the factory ammo. I realize that is most likely not from a snubbie though. The gun in question is a Ruger LCR. They were average 844 fps out of my gun.

Looking at Lyman's data, I would expect their load to be about 839/878 out of their gun for my two loads. Out of my gun they were 712/747. So the Red Dot loads are about 130 fps slower. Compared to factory which was closer to 100 fps slower. The Speer example interests me because it is very soft lead as it is swaged.

To tie this back to the thought in the initial paragraph. What dictates stopping power? The factory +P ammo is only 130 grains. Here is ft/lbs for each load:

factory +P: 206 ft/lbs
Red Dot #1: 171 ft/lbs
Red Dot #2: 188 ft/lbs
Speer: 142 ft/lbs

What is most important? Is it expansion? Penetration would be relevant, but if it penetrates through the entire target, any more is irrelevant. How much of a factor does the impact the bullet makes have?

I suspect any bullet will need a certain velocity to expand in a given media. So it's possible the shorter barrel would hinder the factory ammo's ability to expand at the reduced velocity. I am not positive but I suspect lead might not have the same problem jacketed does with regard to velocity and expansion.

Created Description Notes1 Notes2 Distance Coeff Weight Temp BP Altitude
03-24-2019 1:34:14 PM speer 158 grain swaged trail boss s&b spp 0 1 0 N/A N/A 0
# FPS FT-LBS PF
5 635 0 0
4 647 0 0
3 626 0 0
2 643 0 0
1 ERROR 3
AVG StdDev Min Max Spread TrueMV Shots/Sec Group Size
637.75 9.29 626 647 21 637.75 0.08 0

Created Description Notes1 Notes2 Distance Coeff Weight Temp BP Altitude
03-24-2019 1:34:14 PM speer 158 grain swaged trail boss s&b spp 0 1 0 N/A N/A 0
# FPS FT-LBS PF
5 635 0 0
4 647 0 0
3 626 0 0
2 643 0 0
1 ERROR 3
AVG StdDev Min Max Spread TrueMV Shots/Sec Group Size
637.75 9.29 626 647 21 637.75 0.08 0

Created Description Notes1 Notes2 Distance Coeff Weight Temp BP Altitude
03-24-2019 1:39:54 PM lee 148 grain tl dewc red dot 2.86 grains smoke pc s&b spp 0 1 0 N/A N/A 0
# FPS FT-LBS PF
5 673 0 0
4 720 0 0
3 734 0 0
2 ERROR 3
1 723 0 0
AVG StdDev Min Max Spread TrueMV Shots/Sec Group Size
712.5 27.01 673 734 61 712.5 0.07 0

Created Description Notes1 Notes2 Distance Coeff Weight Temp BP Altitude
03-24-2019 1:44:33 PM lee 148 grain tl dewc red dot 3.06 grains smoke pc s&b spp 0 1 0 N/A N/A 0
# FPS FT-LBS PF
7 770 0 0
6 712 0 0
5 790 0 0
4 746 0 0
3 720 0 0
2 737 0 0
1 754 0 0
AVG StdDev Min Max Spread TrueMV Shots/Sec Group Size
747 27.33 712 790 78 747 0.04 0

Created Description Notes1 Notes2 Distance Coeff Weight Temp BP Altitude
03-24-2019 1:49:36 PM carry 38 +p 0 1 0 N/A N/A 0
# FPS FT-LBS PF
5 876 0 0
4 848 0 0
3 859 0 0
2 807 0 0
1 833 0 0
AVG StdDev Min Max Spread TrueMV Shots/Sec Group Size
844.6 26.24 807 876 69 844.6 0.07 0

[Winger Ed.]

Like everything else-- expansion and penetration is a compromise.

The intended target is a prime governing factor.
How deep a boolit needs to go into it to do what ya want it to do?
Are you shooting a 120 pound deer, a empty soda pop can, or a cape buffalo?

What are the problems with one going all the way through, and beyond?
This may be a consideration for a Police Officer in the bar district.

How accurate at what range does it need to be?
Then, what does it have to do when it gets there?

It easy to over think this stuff, but its not a simple, one size fits all sort of question either.

[weeple2000]

No, I completely agree with you. I was thinking of defensive purposes in this example as it's a snub nose revolver. But I mention Ingot to Target because the author describes different loads that have characteristics specific to their intended target as you describe. As far as going through the target, I think it might be better for a defensive round to dump its energy into the target. I think if the boolit passed straight through it probably missed an opportunity to expand and cause more damage. I think if you shot quenched linotype vs the swaged boolit, the linotype wouldn't be good because it wouldn't expand and probably have more energy after it passed through the target, if it was able to go that far.

[Harter66]

Oh good lord ! Now you've opened and shaken a Texas sized refinery tank can of snakes .

Tissue disruption is the ticket to kill power .
It doesn't matter how you get there as long as the damage is sufficient and where it need to be .
The TD is the result of energy exchange in loss of momentum . The wider the flat and sharper the corners the more effective it is .
So a bore dia flat or cupped nose WC is the maximum effect while a spire/spitzer is the lowest effect . Anything in between is aerodynamic trade-off .
To get some of the trade off back we manipulate alloy , coating , paper patch , powder speeds , primers and maybe even HP , dual alloy or added hardened noses . Expansion only works if it happens after or during the first 1-2" of penetration and will still penetrate to the important parts . Some use CNS others prefer cardio pulmonary damage either way you have to expect to need to break bones and go 12" or more doing it . Through hog parts a 45 Colts at 1000 fps with a 454424 goes 3'+ via 5 ribs and/or will exit through the soft part of the scapula . Expansion I'm told wastes a lot of energy , the math to support that is way over my head but I can see it .

That's about all I have .

[bmortell]

anymore I just think whatever is the fattest and heaviest and goes out the other side is best. its not enough sample size to mean anything, but deer I seen shot with berger bullets in 30-06 (which are very destructive) completely turned lungs and liver to soup and blew baseball size hole out the other side painting the trees but it still just runs as if you threw a pebble at it, not too far but still.

on the other hand .50 muzzleloader hits seem to drop deer more. I hit one with a 250gr at 1350fps which probably impacted at less than 1,000 ft/lbs almost 3 times less energy than 30-06 but it dropped, my family members seem to say the same from deer they got before.

self defense loads I think over penetration is something important to worry about, depending where you are of course, but that changes things a bit.

[BigAlofPa.]

My theory is if a bad guy sees you have a gun. 99.9% of the time he will run away. But if that time comes when you must shoot. I load my defence rounds light to prevent over penetration. I hopes of not injuring an innocent by stander. I like hornady XTP. For in the woods for bears or cougars i carry a hotter load. Everyone will have there opinions on what is best. Hope we never have to test them.

[Rcmaveric]

I can mentally see all points and trade offs. I doubt I have the ability to verbalize it but i will try. There are three ways to kill: central nervous system disruption, exangination (didnt spell that correctly but it means to blead out), and hydraulic shock (disrupts the central nervous system but i separate it).

Doesnt matter what kind of bullet hits the head or neck as long as the bullet breaks what it hits. All animals go DRT when the brain cant talk to the body.

Expansion is more for creating a wound channel in smaller calibers. So expansion is good but it will use energy to expand. Bullets are not very good at transfering their energy into live animals. Think of a pencil passing through something. If the animal is large enough it might not even notice. The wound channel would close and it will take a while for it to bleed out and die. Pluss with a through and through there was very little energy transfer. A lot of hunters talk of anchoring an animal. It takes a large caliber, or enough energy to mushroom a bullet enough to have maximum transfer of energy. This is where flat points, round ballss and wad cutters are soo good. Any thing else is feeding issues and long range aerodynamics. The long nose flat points are the best balance of both worlds. A meplate of about 2/3 diameter of the bullet is what i hear tell is the rule of thumb. No real world experience.

Round balls, flat points and wad cutters have the most surface area on impact. Make them just hard enough to penetrate as far as needed for the game animal. This surface area all ready being there, so expansion isnt as critical or necessary. So energy waste on expansion isnt as needed. So thats more energy to he transfered into the animal or man. You get a nice wound channel for bleeding out. You also get a secondary hydraulic shock. Thats the shock wave of impact that rebounds in the water of the creature. Make the shock wave good enough and it will disrupt the cenetral nevouse system.

Leads into why arrows are so deadly. They have the most efficient energy transfer. Create impressive wound channels. Their hydraulic shock is nuts. There is a video on you tube of a lady. She shoots a bucket of sand in slow mo. It compares a 308 to a 60lb bow (i think. Its been a while). Arrow was more devastating.

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[weeple2000]

I can mentally see all points and trade offs. I doubt I have the ability to verbalize it but i will try. There are three ways to kill: central nervous system disruption, exangination (didnt spell that correctly but it means to blead out), and hydraulic shock (disrupts the central nervous system but i separate it).

...

Believe you mean hydrostatic shock. Here is an excerpt from Ingot to Target describing it. It would have to be above 2600 fps.

http://www.lasc.us/Fryxell_Book_textonly2.pdf

pg 139

Hydrostatic shock
Let’s deal with a couple ill-defined and over-used buzz-words.
“Hydrostatic shock” is held in almost mystical regard by some shooters. What is
hydrostatic shock? High velocity bullets tend to have a larger diameter wound
channel than just the tissue crushed by the bow wave of the bullet as it passes
through (the bullet is generally less than 1” in diameter and the bow wave that
sets up in front of the bullet will usually crush 2-3” of tissue, hydrostatic shock
can rupture blood vessels in a foot or more of soft tissue). The British military
performed extensive ballistic and forensic studies after World War I (back in the
days when "high velocity" was all new and shiny and exciting and different) and
found that “hydrostatic shock” became a significant issue when the bullet's
impact velocity was greater than about 2600 fps.
OK, let’s do some simple analysis. The speed of sound in air is roughly
1000 fps, the speed of sound in water is roughly 4000 fps. If we assume that
the vital zone of a typical game animal is approximately equal parts air (the
volume of the lungs) and water (the primary component of the surrounding soft
tissue), and further approximate that the speed of sound in mixed media is
simply a weighted average of that of its components, then the prediction is that
the “speed of sound” in the vital zone of yon critter is going to be roughly 2500
fps, quite similar to the point that the Brits started to note the presence of this
mysterious phenomenon they called “hydrostatic shock”. Hydrostatic shock is
the result of a high speed pressure wave that ruptures blood vessels, greatly
increasing the amount of hemorrhaging in the wound channel. In a nutshell, it’s
a sonic boom traveling through living tissue. As the bullet passes through the
vitals of an animal going faster than the speed of sound (that is, the speed of
sound in that particular tissue), the “sonic boom” helps to rupture blood vessels
and crush tissue. As the bullet slows down to below the speed of sound (again,
the speed of sound in that particular tissue) this pressure wave collapses, and
the wound channel beyond this point becomes the traditional (sub-sonic) wound
channel. This behavior is obvious when one observes wound channels in
homogenous media like ballistic gelatin, especially with rapidly expanding
bullets (i.e. those that tend to slow down rapidly) that retain significant mass,
like the Nosler Partition. Inspecting the ballistic gelatin wound channels of these
bullets; one sees a large cantaloupe-sized cavity just beneath the surface,
which later collapses to a long, narrow channel. This collapse takes place when
the bullet slows down below the speed of sound in that particular medium. It is
important to recognize that ballistic gelatin has a different density (and hence a
different speed of sound) than does the vital zone of your typical buck, so the
size of each of these features and the point where the bullet slows to below the
speed of sound will be very different in the buck’s vital tissues than in the
denser ballistic gelatin.
140
It is also important to recognize that hydrostatic shock is only delivered
very early in the bullet’s impact, while it is still moving very fast. This mode of
tissue destruction drops off very quickly as the bullet slows down. So, if you
have a large muscular beast with lots of hide, muscle and bone between the
entry point and the vitals (e.g. Cape buffalo, grizzly bear), hydrostatic shock
isn’t likely to play any role at all because the bullet has slowed down to below
the speed of sound (in soft tissue) by the time it reaches the vital organs. But a
smaller animal with relatively little meat between the outer skin and the vitals
(e.g. pronghorn antelope) is more prone to fall over as if electrocuted when
shot with the latest hyper-velocity Eargesplittenloudge-boomer. The reason is
simple, the bullet is still traveling at supersonic (soft tissue supersonic) speeds
as it traverses the vital organs.
A point that is commonly ignored is that hydrostatic shock causes
bloodshot meat (although it's not the only mechanism that causes meat to
become bloodshot), which helps to explain why moderate velocity rounds like
the .30-30 Winchester, .35 Remington, .444 Marlin and .45-70 are so popular
with “meat hunters”.
Since the focus of this book is on cast bullets and since cast bullets are
almost always used at velocities below 2600 fps, hydrostatic shock can be
largely ignored. This 2600 fps is not a fixed number because each species is
built differently, and each animal has a different amount of breath in its lungs
when the bullet hits, and each shot presentation involves different tissues of
different densities. This number undoubtedly varies several hundred fps,
depending on the prey species, shot presentation, elevation, etc. However, the
concept of supersonic impact and its relationship to the nature of the wound
channel is nonetheless important for higher velocity jacketed bullet loads. The
bottom line is that hydrostatic shock can play a significant role in how the .25-
06 kills, it’s probably not much of a contributor for the .44 Magnum.

[Rcmaveric]

Yup thats what i ment. Thanks.

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[fredj338]

Yes the impact vel has a lot to do with whether a bullet expands or not. This is also dependent on the design of the HP & alloy. You an see in this test even 50fps can make a huge diff. Perfect expansion @ about 850fps but below 800fps, uh no.
https://img.photobucket.com/albums/v703/fredj338/45-215gr.jpg (https://smg.photobucket.com/user/fredj338/media/45-215gr.jpg.html)

[weeple2000]

Were those lead? What was the alloy and bhn? What were they shot into?

[Petrol & Powder]

Like everything else-- expansion and penetration is a compromise.

The intended target is a prime governing factor.
How deep a boolit needs to go into it to do what ya want it to do?
Are you shooting a 120 pound deer, a empty soda pop can, or a cape buffalo?

What are the problems with one going all the way through, and beyond?
This may be a consideration for a Police Officer in the bar district.

How accurate at what range does it need to be?
Then, what does it have to do when it gets there?

It easy to over think this stuff, but its not a simple, one size fits all sort of question either.

/\ ALL very true and relevant /\

Between the two factors of penetration and expansion, penetration is the first concern. The bullet MUST reach deep enough to damage something important enough to stop the fight. Expansion is the icing on the cake and it's nice to have good bullet expansion as long as it doesn't hinder the needed penetration. Expansion can make a small bullet more effective as long as it doesn't limit the needed penetration.

I COMPLETELY agree that it is easy to over-think this stuff.

I've also never been attacked by a block of gelatin and I doubt that I ever will be.
Beautifully mushroomed bullets mean very little to the survivors of deadly encounters. Either the bullet stopped the threat in time or it didn't. No one that survived a deadly encounter ever gave a **** what the recovered bullet looked like.

Some people get really hung up on velocity. Others want perfectly mushroomed bullets, Some folks want two holes (entrance & exit), Some like a complete energy dump (bullet doesn't exit). Some people like big holes that extend deep into the target. ......There are nearly endless theories.

In a self defense scenario against human attackers, the only thing that matters is that the bullet stops the attack before the attacker can cause harm or maybe more harm.
In a hunting situation an ethical hunter wants a quick and clean kill.

[pettypace]

Here's a formula that will give a good prediction of bullet penetration in calibrated ballistic gelatin.

Let's take your 152 grain wadcutters at 844 ft/s as an example. Just type this into a google search:

844 ** 0.685 * 152 / 7000 / 0.18 / 0.18 / 3.14

If you don't get an answer of about 21.5, keep trying until you do.

This means that you could expect about 21.5 inches of penetration if you fired your 152 grain wadcutters at a velocity of 844 ft/s into a brick of calibrated ballistic gelatin. The FBI would call that "over-penetration." They want no more than 18". But I wouldn't worry about 21". I'd worry about less than 12" which the FBI considers a minimum.

OK, but what's up with the numbers?

Obviously, the 844 is the velocity in feet/second. The double asterisk means "raised to the power" (an exponent is coming).

So the velocity gets raised to this weird decimal exponent of 0.685. That exponent only works for wadcutters. Different bullet shapes get different exponents.

Next comes multiply by (single asterisk) the bullet weight in grains, in this case it's 152.

Then divide by (the slash /) 7000. That's the number of grains in a pound and it will always be the same.

Then divide by 0.18 (which is the radius of the bullet in inches) twice.

And finally, divide by 3.14 which is that magic "pi" number. (The last three steps -- /.18/.18/3.14 is really just dividing by the cross-sectional area of the bullet.)

I'd better give credit where credit is due. I didn't dream up the formula. It comes from the book Quantitative Ammunition Selection by Charles Schwartz which, despite some annoying shortcomings, is well worth the price and highly recommended.

On the question about "stopping power" the best advice might be that there's no such thing as "stopping power." Any bullet that hits a central nervous system target will instantly stop a badguy. But hitting that target requires good shot placement, good penetration, and good luck. Given those three, a .22 LR might have "stopping power." And absent any one of the three, a .44 Magnum might not.

Finally, I'd suggest to the OP that he keep that Lee wadcutter mould hot and practice, practice, practice. Don't worry about bullet energy. It has nothing to do with the problem. The wadcutter is the best non-expanding bullet shape and with good shot placement and good luck, 21" of penetration is more than enough.

[weeple2000]

Thanks petty. I knew someone would come deliver the goods.

[dverna]

I do not have an answer.

My common sense tells me the best bullet performance would have the bullet expend most of its energy into the target, but still have enough energy to blow a hole out the other side. Expending that energy into the gut or rear end of the target will not be as effective as hitting the heart lungs, and CNS.

I do not want a bullet like fredj338 posted. It needs to perform over a range of velocity.

[Petrol & Powder]

Going back to the first post, getting away from theory and getting into the real world:

The snubnose 38 Special is an outstanding real world fighting tool.

In the mathematical world the snubnose 38 doesn't look very strong but in the real world it has performed far beyond the numbers on paper. However, in the real world two loads have a significant history of success in the short barreled 38 Special;

The "FBI Load" [+P, 158 grain, soft lead semi-wadcutter. hollow point]
and
The Speer Gold Dot HP 135 grain "short barrel" load.

I'm sure other loads may equal the performance of those two but I doubt any new load has a longer track record of success in short barreled revolvers.


I LIKE LONG TRACK RECORDS.

New, improved, cutting edge, sophisticated designed, super duper engineering, blah, blah, blah.......does not beat proven performance. Track records are not absolute but they are the best indicators we have.

In a snubnose you only get 2" of barrel to accelerate the projectile. That projectile then must penetrate at least 12" from any profile presented (front, back, side, up, down, etc.) and it would be nice if it expands a little near the end of that 12"+ of penetration after passing through clothing or other barriers.
There just aren't a lot of magic bullets that will reliably accomplish that task within those limits.

The FBI Load and the Speer Gold Dot at least have a significant body of data to show that they can perform the needed task.

The full charge, solid soft lead wadcutter may be the third cartridge that can meet the above listed criteria with some regularity.

[JBinMN]

I am not going to quote, but I wanted to say that the post by pettypace was extremely helpful to me & well written, IMO.

Can't speak for others, but that was easily understandable by me.

Now I want to find out where to get the
"Different bullet shapes get different exponents." info.
;)

Thanks for posting that formula!
:)

[Dieselhorses]

Impressive posts, and no I am no expert. All I know is that "one bullet does not fit all". "Joe Blow" who sat on a couch for 5 years eating Twinkies and Sara Lee donuts compared to "Johnny Handsome" who's worked out at the gym for 10 years. If both of the latter perps put themselves in a position to get justifiably "popped", I guarantee there'll be different results at center mass. So we can shoot all the bullet gelatin, hams, turkeys, phone books etc. we want. God forbid we ever find ourselves in that position.

I'm sure everyone knows the formula for ft. lbs. (muzzle energy). You can achieve "more energy" with less velocity but with a heavier bullet, but by the same token you can achieve reasonable energy with a lighter bullet with more velocity hence more penetration though.

(velocity x velocity x bullet weight) / 450,437=ft. lbs.

Hey correct me if I'm wrong on anything!

[rking22]

More velocity does not always equate to more penetration. In general, expanding bullets, more velocity will be less penetration. I once tried to finish a deer, literally stuck in a front end, with a 125gr +p 38 Federal self defense load jhp. 2 shots to the neck just below the skull, point blank and neither broke the neck or exited. The 150 gr full charge wad cutter did both. Light for caliber bullets will not penetrate like a std weight or heavy bullet going slower. They are intended to not “over penetrate”, for my needs that does not exist. I am in the 2 hole per shot camp.
To my way of thinking trying to get expansion in a 38 snub is asking for inadequate penetration “on occasion”, and that occasion will be at the worst possible time! +p 158 fbi load has the history to do both, lighter jpgs , no thanks. A solid cast wc on 3.5 of bullseye will penetrate and I don’t expect or hope for expansion. The only instant stop is going to be CNS , and any bullet there will get it done, but it has to get there. That’s on the nut behing the trigger and the bullet construction, in that order!

[Michael J. Spangler]

I’ll leave this here.

https://drive.google.com/drive/mobile/folders/0B_PmkwLd1hmbd3pWYVVJeGlGaFE

[pettypace]

I am not going to quote, but I wanted to say that the post by pettypace was extremely helpful to me & well written, IMO.

Can't speak for others, but that was easily understandable by me.

Now I want to find out where to get the info.
;)

Thanks for posting that formula!
:)

Here are some of the exponents for that penetration formula:

Wadcutters: 0.685
Round Nose: 0.720
Truncated Cone: 0.735
Round Ball: 0.745

There are a few more exponents in Quantitative Ammunition Selection and I highly recommend the book. I bought the Kindle version and it was only a few bucks. But the hard copy is cheap enough and it might make sense to buy one before it goes out of print and folks start asking outrageous prices for used copies.

I also highly recommend Duncan MacPherson's Bullet Penetration which is out of print. The Kindle version is available but a little over-priced. In my opinion, the MacPherson book is better written and has more useful information. But the Schwartz formula and the MacPherson penetration graphs are in surprisingly close agreement.

[weeple2000]

...

Finally, I'd suggest to the OP that he keep that Lee wadcutter mould hot and practice, practice, practice. Don't worry about bullet energy. It has nothing to do with the problem. The wadcutter is the best non-expanding bullet shape and with good shot placement and good luck, 21" of penetration is more than enough.

I have been thinking I should have just gotten the 6 cavity. Reading this thread and other info on the subject makes me appreciate the profile on the bullet nose. The Lee TL358-148-WC is completely flat. So that should be best for creating an optimal wound. A lot of other WC designs have buttons which would be a slight sacrifice.

[bmortell]

and for what its worth id make the double ended wadcutters hard, if anything they would round over when softer instead of expand which would be detrimental to performance. my testing with them in snubs show they grab the rifling better when hard anyway.

[pettypace]

I’ll leave this here.

https://drive.google.com/drive/mobile/folders/0B_PmkwLd1hmbd3pWYVVJeGlGaFE

Thanks for posting that link, Mike. Those International Wound Ballistic Association magazines are a gold mine of good information.