Why is jacket loss generally considered a bad thing. Wouldn’t that equate into another piece of metal doing some internal damage, even considering the assumed faster velocity loss from the much lighter part of the projectile?

I guess I can see it possibly having no real additional benefit but I don’t necessarily understand how it can be a marked detriment.

As you said, the jacket by itself doesn't go very far or add much to the wound channel. Once that's gone, the remaining lead core comes apart much more easily. Bottom line: Less penetration in general

quote:

Once that's gone, the remaining lead core comes apart much more easily

Fair enough but in all the examples I have seen with jacket loss the lead core seems to stay intact. (You know with my super deep knowledge and personal experience with this COUGHBOOKSANDVIDEOCOUGH . ).

So that said assuming the core does stay intact isn’t that still, for example, 215 or whatever a 230 grain .45 minus the jacket weight would weigh still barreling through. (Assuming no projectile break up.). When I say assuming no breakup that is not me insinuating you are incorrect I am just saying in a case where it doesn’t happen to break up.

Thank you this is interesting stuff and good morning food for thought for me.

Chris

Yours is a good question, but whenever we start asking about wound ballistics (a subset of terminal ballistics), the answers become very murky very quickly, not least because of huge emotional investment many shooters have in their opinions.

Because of the complexity of human or animal bodies, converting models and even things like tests in gelatin to expected real world results is extremely difficult. Even if someone like Nazi concentration camp Dr. Mengele had decided to conduct ballistics experiments with live subjects, it would have taken literally thousands of trials to begin to evaluate all the variables, and even then, how would the reactions of a sick and starved concentration camp inmate equate to those of an aggressive healthy attacker? Or, “Okay, you’ve tested a hundred loads; what about this new one?”

Years ago a couple of researchers, Marshall and Sanow, attempted to answer the question of which handgun cartridge bullets and loads were most effective for self-defense purposes by analyzing actual shootings. Although to my knowledge nothing similar was ever attempted before or since, their results were vigorously attacked. A few of the criticisms were obviously valid, such as sample sizes, but others seemed to have been motivated primarily by the emotional investment the critics had in their own beliefs (did I mention emotional investment?).

And what does all that have to do with your question? The answer is that we don’t—and really can’t—know what effect secondary projectiles might have on stopping an aggressor’s deadly assault in a particular incident.

In general much of what we know (and believe) about wound ballistics effects on “stopping power” comes from the experience of big game hunters. One factor that has been a strong belief for as long as I’ve read about the subject (six+ decades) is that a hunting bullet should ideally completely pass through the body of an animal like a deer or elk, and that is in addition to its expanding and causing maximum (or at least a lot of) internal damage. It was evidently found that bullets that tended to break up and shed their jackets didn’t have enough penetration to completely perforate the animals’ bodies. Lack of penetration could result in two things: the bullet didn’t cause enough internal damage to result in a quick kill, and less external bleeding through an exit wound meant that it was harder to track a wounded animal.

Many hunting bullets over the years have been designed to ensure they don’t break up for those reasons. The Nosler Partition was an early one, but other designs have relied on bonding between jacket and core or even bullets made of a single solid metal.

But does all that matter for handgun bullets intended for self-defense? I won’t get into all the things that people believe matter, but to reiterate: we don’t know in general, and we certainly aren’t going to know in a specific incident. Even the articles of faith surrounding how far a handgun bullet should penetrate in gelatin (or shouldn’t penetrate) are mostly arbitrary based on things like one not-immediately-incapacitating shot in the infamous 1986 Miami incident.

One other thing I’ll mention about bullets’ breaking up and shedding their jackets is a claim I read long ago that bullets that break up in gelatin almost always expand in human targets—and is another reminder of one of the differences between test medium and reality.

Handgun rounds rely on sufficient penetration (12-18 inches) for their effectiveness.

Penetration is a balancing act between the mass of the projectile and its velocity.

Slower velocity requires a heavier bullet to achieve sufficient penetration. Lighter projectiles rely on faster velocity to achieve sufficient penetration.

So if you launch a projectile that's a certain mass and a certain velocity that's sufficient for effective penetration, but then split the projectile's mass in two once it hits a target, neither of those resulting lighter weight projectiles will then have sufficient mass to continue to penetrate effectively at its current velocity.

And once these projectiles have left the barrel and are in flight, there is no way to add additional velocity to make up for the lost mass.


Therefore, you want your projectile to retain all of its original mass, even once it has struck the target. This is why things like fragmentary/frangible defensive rounds are not considered effective for defensive use, because of the reduced penetration that necessarily results, and why modern defensive handgun rounds have cores that are either chemically or mechanically bonded to their jackets so that they retain their mass.

I would normally say caliber doesn’t matter assuming duty caliber handguns and premium ammo.

For this question it certainly does. A 230g .45 is going to make for a pretty effective load even with jacket separation vs say a 115g 9mm.

Appreciate all the insights. My example was of a 230 grain .45 was just a caliber and weight that came off the top of my head not specific to the question. But you do raise a good point about it being a heavier projectile all around.