Why JHP over FMJ?

Shawn Dodson said:

Extracts from “The Wound Profile & The Human Body: Damage Pattern Correlation.” (Martin L Fackler, MD, Wound Ballistics Review, 1(4): 1994; 12-19)

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Quoting an MD is rather a moot point because they can be very wrong. Like this one

The lightweight .223 bullets travel at a velocity of about 3,000 feet per second, and after they enter their target, they explode throughout the tissue. As the medical examiner H. Wayne Carver II put it at a news conference Saturday, the bullets’ “energy stays in the body.”

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http://www.washingtonpost.com/natio...fcd1a4-4702-11e2-9648-a2c323a991d6_story.html

Just because they write something, doesn't make them a knowledgeable source.

I'm not doubting these conclusions...because they've apparently been proven out...BUT...Why did the 5.7x28 rds. that were fired at Ft.Hood go through and through sooo many people instead of acting more like the .556...or did I misunderstand something?

Quoting an MD is rather a moot point because they can be very wrong. Like this one

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It appears you're unfamiliar with Dr. Fackler's work.

Shawn,

He was quoting medical examiner H. Wayne Carver II ... not Dr. Fackler.

Understood.

herrwalther is implying that verified and validated wound ballistics information presented by an MD is "moot" because of what H.Wayne Carver II, MD said.

Ironically, the observations documented in Fackler's 1994 paper supports herrwalther's claims in post #44. But I reckon that's "moot" too.

Point is that in the last 20 years terminal performance/wounding effects observed in properly prepared and calibrated 10% ordnance gelatin accurately reflects terminal performance/wounding effects observed in actual shootings. We know that variations in soft tissue densities have negligible effect. We know that bone has greater effect - it is entirely dependent on the exact circumstances of any given shooting (what bone is hit, where it is hit, its location along the wound track, angle of impact, etc.), therefore effects cannot be predicted. (But the results of any given shooting involving bone can be accurately reproduced in ordnance gelatin when the exact circumstances are reconstructed.)

Back in the '70's when I bought my first of many Colt 1911 45's, the only round I would carry was 230gr FMJ 'hardball'. It's a large diameter, heavy, slow-moving round and if you ever find a .45 ACP that has trouble feeding it reliably, then you've got a much bigger problem on your hands. I've tried many of the engineered SD rounds through the intervening years but in order to ensure the lowest probability of semi-auto weapon failure, and a significant potential for penetration and lethality, I have returned to regular carry of the 230 hardball. YMMV....

To each his own. Better to carry a 5.56 carbine with you, in that case...

hedrok said:

I'm not doubting these conclusions...because they've apparently been proven out...BUT...Why did the 5.7x28 rds. that were fired at Ft.Hood go through and through sooo many people instead of acting more like the .556...or did I misunderstand something?

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One factor is that 5.7x28mm has significantly lower velocity (out of a Five-seveN), which in combination with its identical cross-sectional area means that it transfers its energy and momentum much more slowly, allowing it to penetrate more deeply. The same thing happens with 5.56x45mm/.223 when bullet velocity drops by a certain amount due to range (also varies with barrel length). There were many other potential factors in this case, of course, but this was likely one of them, at least.

OK...Then following that line of thought...a 5.7x28 out of a conversion bbl upper on an AR would raise the velocity enough to have a similar effect as the .556 on soft tissue...correct?

I am impressed with the weight of a single 230gr bullet as it rolls about in the palm of my hand. I am impressed with the thought of having it travel in the neighborhood of 580 miles per hour at social distances. Further, I am impressed with the thought that that heavy metal lump, if it has a divot in it, can open up in the dangerous miscreant's flesh to wreak havoc in it, aiding me in my efforts to stop him/her/it, more so than without the divot, I'm all in.

Noise, flash, and punctures are pretty good as long as these are factors on my side, but having bullet expansion too is icing on the cake.

If I must defend myself with a handgun against hardened enemies like berserker hard drives, fmj may be the best way to go, but if flesh is accessible, it's jhp for me.

JHP are the way to go for SD. And the reasons are posted by the previous members expansion is what you want. And hopefully the bullet stays inside the suspect

hedrok said:

OK...Then following that line of thought...a 5.7x28 out of a conversion bbl upper on an AR would raise the velocity enough to have a similar effect as the .556 on soft tissue...correct?

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A 5.7x28mm round would behave more like a 5.56x45mm round in some respects when its velocity is similar, but in that case the latter would have about three times the bullet mass of the former, and therefore three times the energy and momentum, so it would not be fair to say that their effects are comparable. 5.56x45mm (basically equivalent to .223 Remington, for the most part) is a significantly more powerful cartridge that naturally should, at least in theory according to the numbers, cause more damage and be more effective (when the velocity is sufficient to make full use of the energy).

Sorry about the size of the attachments and length of post. This is a 38spl +P+ 110 gr jacketed hollow cavity slug that I put into a rapist as he was trying to escape the scene through me with a knife. Note: Never take a knife to a gun fight.

Almost on cue, Richard Mann sums it up nicely in American Rifleman:

Admittedly, 10 percent ordnance gelatin, as often as it is used and referenced, is not the same as a bad guy. It is simply a ballistic test medium which is thought to offer the same resistance to a bullet as would muscle tissue. It does not replicate skin, ribs, cartilage or fat and, in fact, very often the way a bullet performs in living tissue is quite different than how it performs in gelatin

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FBI standard and often the "ideal" penetration depth for self defense cartridges (in gelatin) is 12 or 13 inches. Depending on which publication you read and caliber. Now I am a rather scrawny guy and my front to back chest cavity distance is just under 10 inches. The 12 to 13 inch standard is a good benchmark to account for how bullets will travel through different media.

Many of us never get beyond shooting at two dimensional targets, unless we're hunters after larger game animals. When we have to shoot defensively, it's best to keep in mind that we only use the surface of the target to locate landmarks that will help us place shots so that the path of our projectiles intersects critical structures within the body. It is my own studied conclusion (and no one has to agree with me) that we only have two factors we can count on as wounding mechanisms - PLACEMENT and PENETRATION. Placement is mostly up to us, penetration is mostly a factor of caliber, bullet design, velocity etc.

IMHO a smaller hole in critical structure is better than a bigger hole in noncritical structure. IIRC Tom Gives phrases it a bit differently, to the effect that 'A good hit with a marginal bullet is better than a marginal hit with a good bullet.' Of course, YMMV.

ETA - some ancient history worth reviewing: http://www.firearmstactical.com/pdf/fbi-hwfe.pdf

And from the late Dave McCracken, originally posted at http://www.thehighroad.org/showpost.php?p=1279935&postcount=42

Here's the Ladder of Effectiveness that we worked out a decade ago on the old Prodigy Net.Effectiveness goes down as the ladder does.

Big holes,center mass.

Small holes, center mass.

Big holes elsewhere.

Small holes elsewhere.

Scare them with the noise.

"Holes", in this context, mean wound channels, both temporary and permanent.

IMHO a smaller hole in critical structure is better than a bigger hole in noncritical structure. IIRC Tom Gives phrases it a bit differently, to the effect that 'A good hit with a marginal bullet is better than a marginal hit with a good bullet.' Of course, YMMV.

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I agree. I have seen too many comments in various places saying bigger holes (from expansion) bleed more or more holes (from thru-and-thru penetration) bleed faster as if the human body was just a bag of blood. It's not. But it does contain organs that resemble bags of blood and those are what you have to put the holes in. When you hit one, expansion may do the most damage, but penetration is still more likely to get you there.

herrwalther writes: "Almost on cue, Richard Mann sums it up nicely in American Rifleman:"

Admittedly, 10 percent ordnance gelatin, as often as it is used and referenced, is not the same as a bad guy. It is simply a ballistic test medium which is thought to offer the same resistance to a bullet as would muscle tissue. It does not replicate skin, ribs, cartilage or fat and, in fact, very often the way a bullet performs in living tissue is quite different than how it performs in gelatin

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Unfortunately, although Richard Mann has tested hundreds of bullets using ballistic gelatin, he doesn't know what he's talking about. And it's sad the NRA is publishing his malarkey in American Rifleman.

Richard Mann promotes, among other things, Marshall/Sanow, the Strasbourg Tests, and bullet selection based on the likelihood of how much "pain" it could produce.

herrwalther writes:

Now I am a rather scrawny guy and my front to back chest cavity distance is just under 10 inches.

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Arms are commonly hit during a gunfight, and if the bullet encounters only soft tissues as it passes through an arm it can reduce a bullet's total penetration potential by as much as 30 percent. That means a bullet that normally penetrates 12-13" may penetrate about 8.5-9" TOTAL. If an arm uses up 3-4" of that total penetration potential then the bullet may penetrate about 5" in the torso.

The best test event for determining general terminal performance, when no intervening barrier material is encountered, is the IWBA four layer denim (4LD) test.

The best test event for determining bullet terminal performance when solid bone is encountered is the FBI automotive windshield test.

Rib bone produces negligible effect on terminal performance in handgun cartridges .38 Special/9mm and larger. Smaller cartridges may be deflected by rib bone due to less bullet mass, less bullet velocity, bullet shape and construction.

Shawn Dodson said:

Richard Mann promotes, among other things, Marshall/Sanow, the Strasbourg Tests, and bullet selection based on the likelihood of how much "pain" it could produce.

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I did not agree with his "pain stops fights." I am sure that pain from a gunshot wound is a reason why bad guy leaves a fight, but there is no measurable pain because it is different for every person. The closest you can really get to pain measuring is "on a scale of 1-10, how much does this hurt?" Not a good basis for comparison. However it is reasonable to imagine that ruptured organs, torn muscles, broken or cracked bones etc do cause pain that would end the fight. But he should have used temporary stretch cavities in ballistic gelatin as a basis for damage potential rather than discussing pain. Since temporary stretch cavities displace internals to cause damage, they are just harder to analyze because they need a very high speed camera to measure.

Since temporary stretch cavities displace internals to cause damage, they are just harder to analyze because they need a very high speed camera to measure.

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Common practice is to measure the radius of the two largest radial cracks produced by the temporary cavity in properly prepared and calibrated ordnance gelatin. The cracks depict the diameter of the temporary cavity within 8% accuracy of the temporary cavity as measured with flash radiography and high-speed cinemaphotography.

"Gelatin is the only tissue simulant reported from which both permanent and temporary cavities can be measured. It is sufficiently elastic to allow the edges of the permanent cavity to return to their original position after being stretched by temporary cavitation, but the limits of elasticity are overcome during the stretch so that the gelatin is fractured. The resultant radially oriented cracks correlate well with temporary cavity diameter."

-- The Wound Profile: A Visual Method for Quantifying Gunshot Wound Components (Martin L. Fackler, MD, and John A. Malinoski, BS; Journal of Trauma, 28(1) Suppl: S21-S29, 1988)

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A Quantum hard drive. Wow, now that's a blast from the past. Quantum was eaten by Maxtor in 2000, which was, in turn, eaten by Seagate in 2006. Those old hard drives were tanks, not at all like the flimsy unreliable crap put out by Seagate nowadays.

The hard drive's age and build quality is probably why it was able to absorb bullets so well. A modern Seagate hard drive wouldn't likely stop it. A Western Digital would, because they still use full-strength cover plates, but not a cheapened Seagate.

Ultimately, though, a hard drive consists of multiple layers of metal, particularly if you strike the platters. It does a good job of stopping a lower-powered bullet. It has nothing on a Mosin Nagant, though.