Petals thru bone

Odd Job · Aug 14, 2011

Also, when you see luceny on an Xray, is that indicative of more of a complete fracture held in place by the surrounding structure(s)/tissues or more likely a fissure that might be a partial/incomplete fracture that hasn't progressed fully through the bone? Are these common at the impact site of a projectile perforation through bone (radially extending from the perforation)?
I am just trying to get an idea of the fracture mechanics involved here so that when I see test results I have at least a simple, if not improved, understanding of what I am seeing.

This requires a long answer with some images. I don't want to mess up the OP's thread so I'll make another one. Stay tuned.

481 · Aug 14, 2011

Odd Job said:
This requires a long answer with some images. I don't want to mess up the OP's thread so I'll make another one. Stay tuned.

I will, count on it.

2zulu1 · Aug 15, 2011

Odd Job said:
This requires a long answer with some images. I don't want to mess up the OP's thread so I'll make another one. Stay tuned.

OP is flexible, Hi-Power test in the morning.

Bob

newbuckeye · Aug 15, 2011

Great thread! I am glad to see my choice of rounds fairing well in your tests!

2zulu1 · Aug 15, 2011

9mm 124gr+P GD bone

Slight rain delay this AM, Browning Hi-Power was used in today's test, bullet would cut into right edge of bone; but more on that later:

Bullet retained 124.4grs;

Asymetrical expansion was 0.642", 1.81x caliber;

On my mind for today's test was the deflection of the handloaded 10mm/180gr Nosler JHP that also cut through the edge of a cow bone. I don't have an explanation as to why the lighter 9mm JHP stayed true to course and the heavier, faster moving 10mm bullet didn't.

Going back and reconstructing this test, we can observe why the Gold Dot expanded in an asymetrical manner. I was fortunate enough to cut into the bone about 1/2 caliber; the result:

What I interpet in the above picture is a snapshot in time, bullet rotation during a ~0.5" travel distance and the reason why 2 petals did not fold back as the remaining 4 did. The hole in the plastic bottle was also elongated as displayed by the bullet placed in the hole.

Given the very wide expansion, penetration for this GD will be much less than the 4 layer denim baseline test.

9mm 124 gr. +P Gold Dot JHP @ 1220 fps v. four layers of denimVi = 1220 feet per second
Mr = 124 grains
Dr = 0.587 inch

Vcav = 408.327 feet per second
Mw = 39.374 grams (1.389 ounce)
Xcm = 31.695 centimeters (12.478 inches)

Today's test data;
MV 1220fps
Mr 124.4grs
Dr 0.642"

Bob

481 · Aug 15, 2011

2zulu1 said:
Slight rain delay this AM, Browning Hi-Power was used in today's test, bullet would cut into right edge of bone; but more on that later:

Bullet retained 124.4grs;

Asymetrical expansion was 0.642", 1.81x caliber;

On my mind for today's test was the deflection of the handloaded 10mm/180gr Nosler JHP that also cut through the edge of a cow bone. I don't have an explanation as to why the lighter 9mm JHP stayed true to course and the heavier, faster moving 10mm bullet didn't.

Going back and reconstructing this test, we can observe why the Gold Dot expanded in an asymetrical manner. I was fortunate enough to cut into the bone about 1/2 caliber; the result:

What I interpet in the above picture is a snapshot in time, bullet rotation during a ~0.5" travel distance and the reason why 2 petals did not fold back as the remaining 4 did. The hole in the plastic bottle was also elongated as displayed by the bullet placed in the hole.

Given the very wide expansion, penetration for this GD will be much less than the 4 layer denim baseline test.

9mm 124 gr. +P Gold Dot JHP @ 1220 fps v. four layers of denim
Vi = 1220 feet per second
Mr = 124 grains
Dr = 0.587 inch

Vcav = 408.327 feet per second
Mw = 39.374 grams (1.389 ounce)
Xcm = 31.695 centimeters (12.478 inches)

Today's test data;
MV 1220fps
Mr 124.4grs
Dr 0.642"

Bob

Nice reconstruction, Bob.

Man, I don't care who you are- the HP is one helluva sexy gun. Something about those lines. Intangible, but definitely a classic design.

The Gold Dot design is an exceptional design IMO. This one really let loose despite the barrier placed before it.

Here is the MacPherson predictive analysis for this test:

Speer 9mm 124 gr. +P Gold Dot JHP (53617) v. heavy bone
Recovered Projectile Data:
Average Recovered Diameter: 0.642 inch (1.812x caliber)
Retained Mass: 124.4 grains
Impact Velocity: 1220 feet per second

Predicted Performance:
Cavitation Regime Boundary (Vc) = 394.836 feet per second
Permanent Wound Cavity Mass (Mw) = 40.468 grams (1.428 ounces)
Penetration Depth (Xcm) = 27.802 cm (10.946 inches)

As you suspected, due to significantly greater expansion, this one went a little shallower than the baseline but the reduction in predicted penetration was about 1.5 inches (that's a penetration loss of a little more than 12%), not that bad considering what the JHP had to go through to get there.

Thanks, Bob.

JTQ · Aug 15, 2011

Thanks for the hard work and expense of doing these tests. I find them fascinating.

I always hope to see a "control" round in tests like these. Set up a baseline for performance such as 230 gr. ball ammo, or 200 gr. semi-wadcutter rounds in .45ACP. These are probably the most shot rounds in .45ACP, yet both are virtually absent from tests done by law enforcement or ammo makers.

I realize both would most likely penetrate more and expand less than their hollow point brethren, but the comparison would be nice to see.

481 · Aug 15, 2011

JTQ said:
Thanks for the hard work and expense of doing these tests. I find them fascinating.

I always hope to see a "control" round in tests like these. Set up a baseline for performance such as 230 gr. ball ammo, or 200 gr. semi-wadcutter rounds in .45ACP. These are probably the most shot rounds in .45ACP, yet both are virtually absent from tests done by law enforcement or ammo makers.

I realize both would most likely penetrate more and expand less than their hollow point brethren, but the comparison would be nice to see.

JT,

Because the .45ACP 230 gr. FMJRN @ 850 +/- 25 fps fps and other similar "un/less likely to-expand" designs are unlikely to expand in such tests (using either calibrated ordnance gelatin or water test medium), it is easier to just "plug the parameters in" to MacPherson's predictive equations (empirically researched in his book by firing over 400 rounds into over a ton of calibrated gelatin) and "skip" the test since it would take an awful lot of water to stop such a projectile. (somewhere between 60 and 75 inches of "water column" depending upon impact velocity)

For the sake of comparison, here are a few predicted penetration depths using ρ set to 1.030 grams/cubic centimeter for soft tissue/calibrated gelatin:

9mm 115 gr. FMJRN @ 1155 fps: 28.0"

9mm 124 gr. FMJRN @ 1120 fps: 29.7"

9mm 147 gr. FMJTC @ 975 fps: 34.7"

.40 155 gr. FMJTC @ 1160 fps: 32.4"

.40 165 gr. FMJTC @ 1125 fps: 33.9"

.40 180 gr. FMJTC @ 950 fps: 33.5"

.45 185 gr. FMJTC @ 975 fps: 28.1"

.45 230 gr. FMJRN @ 850 fps: 29.7"

That help?

Usertag · Aug 15, 2011

What an expansion! That was a perfectly executed round. Every HP I see usually expands and goes into one-billion pieces. The Federal and the Winchester did great. But I would expect that from Federal.

Rail Driver · Aug 16, 2011

I'd like to see the tests with FMJ, though I know expansion won't be nearly as drastic, would there be any at all? The numbers don't really tell a lot of us less technical folks a whole lot.

2zulu1 · Aug 16, 2011

481 said:
JT,

Because the .45ACP 230 gr. FMJRN @ 850 +/- 25 fps fps and other similar "un/less likely to-expand" designs are unlikely to expand in such tests (using either calibrated ordnance gelatin or water test medium), it is easier to just "plug the parameters in" to MacPherson's predictive equations (empirically researched in his book by firing over 400 rounds into over a ton of calibrated gelatin) and "skip" the test since it would take an awful lot of water to stop such a projectile. (somewhere between 60 and 75 inches of "water column" depending upon impact velocity)

For the sake of comparison, here are a few predicted penetration depths using ρ set to 1.030 grams/cubic centimeter for soft tissue/calibrated gelatin:

9mm 115 gr. FMJRN @ 1155 fps: 28.0"

9mm 124 gr. FMJRN @ 1120 fps: 29.7"

9mm 147 gr. FMJTC @ 975 fps: 34.7"

.40 155 gr. FMJTC @ 1160 fps: 32.4"

.40 165 gr. FMJTC @ 1125 fps: 33.9"

.40 180 gr. FMJTC @ 950 fps: 33.5"

.45 185 gr. FMJTC @ 975 fps: 28.1"

.45 230 gr. FMJRN @ 850 fps: 29.7"

That help?

So, how did the original 130gr FMJ in .38Super/1300fps do?

Also in .38Super, handloaded 147gr FMJ at 1288fps?

Bob

481 · Aug 16, 2011

Rail Driver said:
I'd like to see the tests with FMJ, though I know expansion won't be nearly as drastic, would there be any at all? The numbers don't really tell a lot of us less technical folks a whole lot.

Rail Driver,

Unless they strike something hard and strong enough to deform them, FMJs typically show no expansion after penetration through only soft tissue.

The numbers provided above in my prior post to JTQ are nothing more than maximum potential depths of penetration expressed in inches for each weight and FMJ configuration impacting at the specified velocity if it were fired into test media long enough to contain it until it came to a stop and could go no further. (imagine shooting into a very long test block of ordnance gelatin)

Not very technical at all- just maximum penetration in inches.

I hope this clears it up for you.

481 · Aug 16, 2011

2zulu1 said:
So, how did the original 130gr FMJ in .38Super/1300fps do?

Also in .38Super, handloaded 147gr FMJ at 1288fps?

Bob

Sure.

.38 Super 130 gr. FMJRN @ 1300 fps: 33.99"

.38 Super 147 gr. FMJFP @ 1288 fps: 40.86"

If you want penetration against soft tissue, either load would provide a lot of it.

JTQ · Aug 16, 2011

In reference to why not FMJ,

481 wrote,
Unless they strike something hard and strong enough to deform them, FMJs typically show no expansion after penetration through only soft tissue.

From the very first post in this thread

2zulu1 wrote,
see how bullets (ammunition) perform against some big, tough, bleached out range (as in open range) cow bones.

I think that is what is happing with, the "big, tough, bleached out range cow bones". I would think they would be hard enough and strong enough to deform them.

The ballistic gelatin test has been around for so long all the maker's top bullets pretty much perform the same. Penetration is within a couple of inches of each other (within the same caliber and bullet weight), weight retention within a few grains, and expansion within hundredths of an inch. There really isn't much of a measurable difference until you get to different style of bullet.

I think ball or semi-wadcutters would be interesting to test simply because they are different, but it isn't my test and I'm not doing the work or spending the cash. I do appreciate the testing and hard work expended, though. Keep up good work it is very interesting to follow.

481 · Aug 16, 2011

JTQ said:
I think ball or semi-wadcutters would be interesting to test simply because they are different, but it isn't my test and I'm not doing the work or spending the cash. I do appreciate the testing and hard work expended, though. Keep up good work it is very interesting to follow.

I am not sure, but Bob may've shot such a test in the past. I know for a fact that I haven't done so, but he may be able to post something that will satisfy your curiosity about such designs.

481 · Aug 16, 2011

As I promised earlier in this thread, here are the results for the test of the WinchesterUSA 9mm 147 gr. JHP-

Here is the MacPherson predictive analysis for this test:

WinchesterUSA 9mm 147 gr. JHP (USA9JHP2) v. four layers of 2 ounce cotton fabric

Recovered Projectile Data:
Average Recovered Diameter: 0.583 inch (1.645x caliber)
Retained Mass: 147.6 grains
Impact Velocity: 979.2 feet per second

Predicted Performance:
Cavitation Regime Boundary (Vc) = 410.367 feet per second
Permanent Wound Cavity Mass (Mw) = 41.523 grams (1.465 ounces)
Penetration Depth (Xcm) = 33.628 cm (13.240 inches)

Rail Driver · Aug 16, 2011

I think ball or semi-wadcutters would be interesting to test simply because they are different

I actually like this idea... I use lead SWC in my carry 1911 Commander, and would love to see what these do to "fresh" bone (I wish I had a hog torso to donate. fair approximation to human). Maybe I'll have to go hunting and subsequently conduct my own test...

481 · Aug 17, 2011

Another test of the WinchesterUSA 9mm 147 gr. JHP with different and very interesting results-

Here is the MacPherson predictive analysis for this test:

WinchesterUSA 9mm 147 gr. JHP (USA9JHP2) v. four layers of 2 ounce cotton fabric

Recovered Projectile Data:
Average Recovered Diameter: 0.515 inch (1.453x caliber)
Retained Mass: 122.2 grains, jacket separation occurred
Impact Velocity: 978.3 feet per second

Predicted Performance:
Cavitation Regime Boundary (Vc) = 425.923 feet per second
Permanent Wound Cavity Mass (Mw) = 33.718 grams (1.189 ounces)
Penetration Depth (Xcm) = 34.786 centimeters (13.695 inches)

Conventional (unbonded "cup and core" construction) Winchester JHPs regardless of caliber have a jacket that comprises about 17% of total projectile weight so when jacket separation occurs (all brands of unbonded JHPs are subject to this), momentum (ρ = mass x velocity) is reduced and performance suffers. Although penetration depth is similar, Mw is significantly less than the prior test of the same ammunition under the same conditions due to a smaller expanded diameter.

As much as I like to see a "perfect" test, the "failures" are what I find most illuminating.

bergmen · Aug 17, 2011

481 said:

This is really good to know, this is all I've carried for years.

Good, reliable, accurate, perfect feeding, easily affordable, readily available (Wally World).

Dan

Elm Creek Smith · Aug 17, 2011

Could you test the Remington .357 Magnum 125 grain JHP?

Thanks.

ECS

2zulu1 · Aug 18, 2011

Elm Creek Smith said:
Could you test the Remington .357 Magnum 125 grain JHP?

Thanks.

ECS

I have some baseline numbers for .357mag/125gr JHPS.

M686+/6"

.357 Magnum Remington 125 gr. SJHP (L357M1B) v. four layers of denim
Vi = 1627 feet per second
Mr = 122.2 grains
Dr = 0.641 inch

Vc = 397.688 feet per second
Mw = 44.922 grams (1.585 ounces)
Xcm = 30.545 cm (12.025 inches)

Dan Wesson/4"

.357 Magnum Remington 125 gr. SJHP v. four layers of denim from a 4 inch barrel
Vi = 1456 feet per second
Mr = 111.9 grains
Dr = 0.622 inch

Vc = 401.294 feet per second
Mw = 38.992 grams (1.375 ounces)
Xcm = 28.555 cm (11.242 inches)

M686+/6" handload

.357 Magnum Remington Golden Sabre 125 gr. JHP v. four layers of denim
Vi = 1621 feet per second
Mr = 125.2 grains
Dr = 0.613 inch

Vcav = 403.052 feet per second
Mw = 45.641 grams (1.610 ounces)
Xcm = 33.371 centimeters (13.138 inches)

M686+/6" handload

Speer .357 Magnum 125 gr. Gold Dot v. four layers of denim
Vi = 1626 feet per second
Mr = 118.6 grains
Dr = 0.534 inch

Vcav = 420.085 feet per second
Mw = 42.668 grams (1.505 ounce)
Xcm = 39.931 centimeters (15.721 inches)

Bob

2zulu1 · Aug 18, 2011

JTQ said:
Thanks for the hard work and expense of doing these tests. I find them fascinating.

I always hope to see a "control" round in tests like these. Set up a baseline for performance such as 230 gr. ball ammo, or 200 gr. semi-wadcutter rounds in .45ACP. These are probably the most shot rounds in .45ACP, yet both are virtually absent from tests done by law enforcement or ammo makers.

I realize both would most likely penetrate more and expand less than their hollow point brethren, but the comparison would be nice to see.

I can test both the .45auto/200gr SWC and 230gr FMJ-WWB. I'll attempt to deform both types of bullets against thick bone.

Bob

JTQ · Aug 18, 2011

2zulu1 wrote,
I can test both the .45auto/200gr SWC and 230gr FMJ-WWB. I'll attempt to deform both types of bullets against thick bone.

Thanks.

You don't have to try and deform them, whatever happens, happens.

I've found this article to be an interesting one concerning bullet shape and penetration.
http://www.gsgroup.co.za/articlepvdw.html

I have seen several gelatin tests with ball ammo (rifle and pistol) where the round did yaw and ended up exiting the media along the side rather than penetrate straight through as you more often see with wadcutter/semi-wadcutter and hollow point bullets.

481 · Aug 18, 2011

Thanks for the link, JT.

That article offers by far the best explanation I've seen in a long while of the phenomena of (super)cavitation and how it facilitates the deep penetration produced by flatnose and truncated cone nose projectiles. The effect is counter-intuitive to most not familiar with the discipline of fluid dynamics, but once the mechanics are understood, it is really amazing to see how simple it really is.

When a body moves through a fluid at high speed and the fluid has to move around it at a rapid pace, the pressure in the flow area drops in terms of Bernoulli’s law. In the case of a bullet traveling through a medium such as water (or animal tissue containing huge percentages of water), the water or tissue has to flow around the bullet.
The faster the bullet travels through the water, the more the pressure in the flow decreases and a point can be reached where the flow pressure equals the vapour pressure of water (or any other medium it is traveling through). When that occurs, the water converts to gas and bubbles or cavities appear and that constitutes cavitation. The sharper the edge across which the flow occurs (such as a semi-wadcutter leading edge), the easier it happens. The more the cavitation due to faster flow (higher velocities) the more rapid the extent of cavitation, until a point is reached where all the small vapour bubbles fuse into a large, stable bubble around the bullet. The single large bubble enveloping the bullet constitutes supercavitation. The effect of which is that only the meplat on the bullet nose remains in contact with the terminal medium. The rest of the bullet travels in a capsule of low-pressure tissue vapour, much more comparable to air than water or flesh.
While encapsulated in this low pressure cavity, penetration reducing drag on the bullet as well as its tendency to tumble is reduced because it travels in a virtual atmospheric medium – not the 30-40 times denser water or body tissue.

JTQ · Aug 18, 2011

Most likely the reason Jeff Cooper favored the truncated cone bullet as a replacement for ball ammo.

Petals thru bone

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