Ballistics by the inch

Reprise: Is Muzzle Energy Really a Measure of Handgun Effectiveness?

Prompted by my friends over at the Liberal Gun Club, this is another in an occasional series of revisiting some of my old articles which had been published elsewhere over the years, perhaps lightly edited or updated with my current thoughts on the topic discussed. This is an article I wrote for Guns.com, and it originally ran 2/13/2012. Some additional observations at the end.

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Would you rather be shot with a modern, Jacketed Hollow Point bullet from a .32 ACP or have someone throw a baseball at you? Seems like a silly question, doesn’t it? But did you know that the ‘muzzle energy’ of the two is about the same? Seriously, it is and that’s just one reason why trying to use muzzle energy as a measurement of handgun effectiveness is problematic.

Calculating Muzzle Energy

First off, what is ‘muzzle energy’ (ME)? Wikipedia has a pretty good description and discussion of it. Here’s the simple definition:

Muzzle energy is the kinetic energy of a bullet as it is expelled from the muzzle of a firearm. It is often used as a rough indication of the destructive potential of a given firearm or load. The heavier the bullet and the faster it moves, the higher its muzzle energy and the more damage it will do.

For those who are trying to remember your high school physics, kinetic energy is the energy (or power) of something moving. You can calculate kinetic energy using the classic formula:

E = 1/2mv^2

Which is just mathematic notation for “Energy equals one-half the mass of an object times the square of its velocity.”

Doing the actual calculations can be a bit of a pain, since you have to convert everything into consistent units, but the formula is there on the Wikipedia page (and can be found elsewhere) if you want to give it a go. Fortunately, there are a number of websites out there which will calculate muzzle energy for you – you just plug in the relevant numbers and out comes the result. We also have muzzle energy graphs for all the calibers/ammunition tested at BBTI.

Batter up?

If you go through and check all the muzzle energy numbers for handguns with a 6″ or less barrel which we’ve tested (BBTI that is), in .22, .25. or .32, you’ll see that all except one (and you’ll have to go to the site to see which one it is) comes in under 111 foot-pounds.

Why did I choose that number? Because that would be the kinetic energy of a baseball thrown at 100 mph. Check my numbers: a standard baseball weighs 5.25 ounces, which is about 2,315 grains. 100 mph is about 147 fps. That means the kinetic energy of a baseball thrown at 100 mph is 111 ft-lbs.

Now, we’re not all pro baseball pitchers. And I really wouldn’t want to just stand there and let someone throw a baseball at me. But I would much rather risk a broken bone or a concussion over the damage that even a small caliber handgun would do.

The Trouble with Muzzle Energy

And therein lies the problem with using muzzle energy as the defining standard to measure effectiveness: it doesn’t really tell you anything about penetration. A baseball is large enough that even in the hands of Justin Verlander it’s not going to penetrate my chest and poke a hole in my heart or some other vital organ. If I catch one to the head, it may well break facial bones or even crack my skull, but I’d have a pretty good chance of surviving it.

Now, I think muzzle energy is a useful measure of how much power a given handgun has. That’s why we have it available for all the testing we’ve done on BBTI. But it is just one tool, and has to be taken into consideration with other relevant measures in order to decide the effectiveness of a given gun or caliber/cartridge. Like measures such as depth of penetration. And temporary and permanent wound channels. And accuracy in the hands of the shooter. And ease of follow-up shots. And ease of carry.

I’ve seen any number of schemes people have come up with to try and quantify all the different factors so that you can objectively determine the “best” handgun for self defense. Some are interesting, but I think they all miss the point that it is an inherently subjective matter, where each individual has to weigh their own different needs and abilities.

Sure, muzzle energy is a factor to consider. But I think the old adage of “location (where a bullet hits) is king, and penetration is queen” sums it up nicely.

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In the five years since I wrote that, my thinking has evolved somewhat. Well, perhaps it is better to say that it has ‘expanded’. I still agree with everything above, but I’m now even more inclined to go with a relatively heavy bullet for penetration over impressive ME numbers. I think that comes from shooting a number of different brands of ammo where the manufacturer has chosen to go with a very fast, but very light bullet to get an amazing ME, with the argument that this is more likely to cause some kind of terminal shock, citing tests showing significant ‘temporary wound channels’ and such in ballistic gel.

But you really can’t cheat physics. If you dump a lot of kinetic energy very quickly into creating a temporary wound channel, then you have less energy for other things. Like penetration. Or bullet expansion. And those are factors which are considered important in how well a handgun bullet performs in stopping an attacker. That’s why the seminal FBI research paper on the topic says this:

Kinetic energy does not wound. Temporary cavity does not wound. The much discussed “shock” of bullet impact is a fable and “knock down” power is a myth. The critical element is penetration. The bullet must pass through the large, blood bearing organs and be of sufficient diameter to promote rapid bleeding. Penetration less than 12 inches is too little, and, in the words of two of the participants in the1987 Wound Ballistics Workshop, “too little penetration will get you killed.” Given desirable and reliable penetration, the only way to increase bullet effectiveness is to increase the severity of the wound by increasing the size of hole made by the bullet. Any bullet which will not penetrate through vital organs from less than optimal angles is not acceptable. Of those that will penetrate, the edge is always with the bigger bullet.

 

Now, you can still argue over the relative merits of the size of the bullet, and whether a 9mm or a .45 is more effective. You can argue about trade-offs between recoil & round count. About this or that bullet design. Those are all completely valid factors to consider from everything I have seen and learned about ballistics, and there’s plenty of room for debate.

But me, I want to make sure that at the very minimum, the defensive ammo I carry will 1) penetrate and 2) expand reliably when shot out of my gun. And if you can’t demonstrate that in ballistic gel tests, I don’t care how impressive the velocity of the ammo is or how big the temporary wound cavity is.

So I’ll stick with my ‘standard for caliber’ weight bullets, thanks. Now, if I can drive those faster and still maintain control of my defensive gun, then I will do so. Because, yeah, some Muzzle Energy curves are better than others.

 

Jim Downey

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April 16, 2017 Posted by | .22, .25 ACP, .32 ACP, .45 ACP, .45 Super, 9mm Luger (9x19), Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , , | 1 Comment

Reprise — Storing Ammo Long-term: Because without Rounds, Your Gun Is Just a Poorly Designed Club

Prompted by my friends over at the Liberal Gun Club, this is another in an occasional series of revisiting some of my old articles which had been published elsewhere over the years, perhaps lightly edited or updated with my current thoughts on the topic discussed. This is an article I wrote for Guns.com, and it originally ran 8/17/2011. Some additional observations at the end.

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It’s a classic scene: Mad Max rolling a shotgun shell between his fingers, trying to see whether it is still any good.

Will it crumble? If it doesn’t, will it still fire?

Only his script-writer knows for sure.

But how much does it have to do with reality? How long will ammunition stay good, and under what storage conditions? Talk about classics – that basic question has been a standard of firearm discussions online going back to before there even was an “online”.

Whether you’ve just found an old box of shotgun shells in the back of your closet or you’re planning ahead for the Zombie Apocalypse, it’d be good to know whether you could trust those rounds to go bang when needed.

So, what’s the answer?

Well, it depends.

Chances are, if the ammunition has been made in the last century, and has been stored reasonably well, then it’ll still be good.

OK, let’s qualify, qualify, qualify that statement. Chances are, if it was a quality factory ammunition, made in the last century, and has been stored reasonably well, then it’ll still be good.

Chances are, if it was a quality factory ammunition, made in the last century using modern smokeless powder, and has been stored reasonably well, then it’ll still be good.

Chances are, if it was a quality factory ammunition, made in the last century using modern smokeless powder and with a non-corrosive primer, and has been stored reasonably well, then it’ll still be good.

Chances are, if it was a quality factory ammunition, made in the last century using modern smokeless powder and with a non-corrosive primer, and hasn’t been immersed in water or subject to prolonged sub-freezing temperature, then it’ll still be good.

Hmm. That makes it sound like there’s not a good chance, doesn’t it?

But I don’t mean to say that. The truth is, if you come across a box (or can or pallet) of ammo made after WWII, and the exterior doesn’t show signs of obvious damage or corrosion, it should be fine. I’ve shot plenty of such ammo over the years – stuff that is older than I am. And it’s likely that if the ammunition was made after the shift to non-corrosive primers in the 1920s – which covers most non-military ammunition – it’ll also be fine. In the West, even military ammunition made since WWII has predominantly been made using non-corrosive primers, and is likely very stable. Eastern bloc countries used corrosive primers until much, much later, which meant not only could they present a problem with barrel damage if the firearm wasn’t cleaned properly, but that there was a chance that the primer would become weak with age and wouldn’t completely ignite the gunpowder in the cartridge.

How about storage? I mean of ammo made recently – how should you store it to increase the chances of it staying good?

The biggest thing is to keep it from resting in water. Sounds like a no-brainer but you’d be surprised.

Some ammunition is sealed (tracer rounds, for example) after manufacture. But most of it just relies on the mechanical qualities of manufacturing to keep moisture out. This is actually pretty good, and serves fairly well in the case of metallic cartridges. You don’t have to worry about a brief exposure to water, from rain or dropping a round into a puddle or something. You should avoid allowing non-sealed rounds from sitting in water for a prolonged period, since such exposure could allow water to seep into the cartridge and compromise the gunpowder. It could also lead to case or primer corrosion, which could weaken the structural integrity or loading problems. So, if you want to store ammo for a long time, keep it in some kind of waterproof container. Double-bagging, using a vacuum sealer, and related strategies should all work fine.

Oh – did you notice that I specified “metallic cartridges” above? Yeah. That’s because plastic shotgun shells are not as water-tight. They’re still pretty good, given modern manufacturing tolerances, but you probably want to be a little more careful with them for long-term storage. Just sayin’.

One other thing to be aware of: freezing can cause some gunpowders to “crack” – to make smaller particles. While it may not seem to be a big deal, it can greatly increase the surface area of each small particle of the propellent. Which can cause it to burn faster. Which can cause over-pressure. Which can cause case rupture or even potentially the dreaded “ka-boom.”

So, there you have it, whether you’re wanting to have a rainy-day stash, just stockpile ammo when you find a good sale, or are wanting to be accurate for your next screenplay – take these things into consideration and you should be fine. Modern ammunition is generally of very high quality, and very reliable. A little planning ahead on your part should maintain that reliability for as long as you want.

Because it’s better to have a gun than a club.

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There’s isn’t a lot that I would add to this piece regarding old ammo. But since I wrote this we’ve tested something like an additional 20,000 rounds of new commercial ammo from the biggest manufacturers to boutique ammo from small shops. And I continue to be impressed with just how uniform the quality has been — it’s easily in the 99%+ range. It’s to the point where if commercial ammo fails to fire reliably, I would always first inspect the gun to see what the problems was, because it’s much more likely that the gun has some kind of problem than the ammo.

Which isn’t to say that all ammo will work reliably in all guns. I still advocate that for self-defense firearms in particular, you should always run at least a couple of boxes of a given type/brand of ammo through the gun before considering it sufficiently reliable enough to depend on to save your life. YMMV, of course.

Jim Downey

April 9, 2017 Posted by | Anecdotes, Data, Discussion., Shotgun ballistics | , , , , , , , , , , , , , , , , | Leave a comment

Reprise: Levering the Playing Field: a Magnum Opus

Prompted by my friends over at the Liberal Gun Club, this is another in an occasional series of revisiting some of my old articles which had been published elsewhere over the years, perhaps lightly edited or updated with my current thoughts on the topic discussed. This is an article I wrote for Guns.com, and it originally ran 3/26/2011. Some additional observations at the end.

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In an earlier article, when I said you’d get about a 15% increase in bullet velocity when using a pistol caliber carbine over a handgun, I lied.

Or, rather, I was neglecting one particular class of pistol ammunition which can develop upwards of a 50% increase in velocity/power in a carbine over a handgun: the “magnums,” usually shot out of a lever-action gun. This would include .327 Federal Magnum, .357 Magnum, .41 Magnum, and .44 Magnum.

These cartridges are rimmed, initially developed as powerful handgun rounds, and have their origins in black powder cartridges. This history is important for understanding why they are different than most of the other pistol cartridges and the carbines that use them.

We’ll start with the .357 Magnum, the first of these cartridges developed.

Back in the 1930s a number of people, Elmer Keith most notable among them, were looking to improve the ballistic performance of the .38 Special cartridge. This had been a cartridge originally loaded with black powder. Black powder takes up a lot of space – typically two to four times as much space as smokeless powder of a similar power. Meaning that when people started loading .38 Special cartridges with smokeless powder, the cartridge was mostly empty.

Now, if you were looking to get more power out of a .38 Special, and you saw all that unused space in the cartridge, what would be the obvious thing to do? Right – add more smokeless powder.

The problem is, many of the handguns chambered for the .38 Special using black powder were not strong enough to handle .38 Special cartridges over-charged with smokeless powder. And having handguns blowing up is rough on the customers. Heavier-framed guns could handle the extra power, but how to distinguish between the different power levels and what cartridge was appropriate for which guns?

The solution was to come up with a cartridge, which was almost the same as the .38 Special, but would not chamber in the older guns because it was just a little bit longer. This was the .357 Magnum.

There are two important aspects of the cartridge as far as it applies to lever guns. One is just simply the ability to use more gunpowder (a typical gunpowder load for a .357 magnum uses about half again as much as used in a .38 Special.) And the other is that you can get more complete combustion of the gunpowder used, perhaps even use a much slower burning gunpowder. This means that the acceleration of the bullet continues for a longer period of time.

How much of a difference does this make? Well, from the BBTI data for the .357 Magnum, the Cor Bon 125gr JHP out of a 4″ barrel gives 1,496 fps – and 2,113 fps out of an 18″ barrel. Compare that to the .38 Special Cor Bon 125gr JHP out of a 4″ barrel at 996 fps and 1,190 fps out of an 18″ barrel. That’s a gain of 617 fps for the .357 Magnum and just 194 fps for the .38 Special. Put another way, you get over a 41% improvement with the Magnum and just 19% with the Special using the longer barrel.

Similar improvements can be seen with other loads in the .357 Magnum. And with the other magnum cartridges. And when you start getting any of these bullets up in the range of 1,500 – 2,000 fps, you’re hitting rifle cartridge velocity and power. The low end of rifle cartridge velocity and power, but nonetheless still very impressive.

There’s another advantage to these pistol caliber lever guns: flexibility. Let’s take that .357 again. On the high end of the power band, you can use it as a reliable deer-hunting gun without concern. But if you put some down-loaded .38 Special rounds in it, you can also use it to hunt rabbit or squirrel. I suppose you could even use snake/rat shot loads, though most folks don’t recommend those loads due to concerns over barrel damage. Shooting mild .38 Special loads makes for a great day just plinking at the range.

One thing that I consider a real shame: you can get good quality lever guns for the .357, the .41, and the .44 magnums. But to the best of my knowledge, no one yet makes a .327 Magnum lever gun. I would think that such a gun would meet with a lot of popularity – properly designed, it should be able to handle the .327 Federal Magnum cartridge, the .32 H&R cartridge, even the .32 S&W Long. Again, with the right powder loads, this would give the gun a great deal of flexibility for target shooting and hunting small to medium sized game/varmits.

So, if you like the idea of having a carbine in the same cartridge as your handgun, but want to be able to maximize the power available to you, think about a good lever gun. It was a good idea in the 19th century, and one that still makes a lot of sense today.

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Some additional thoughts …

I’m still a little surprised that no manufacturer has come out with a production .327 mag lever gun, though occasionally you hear rumors that this company or that company is going to do so. But I must admit that as time has gone on I’ve grown less interested in the .327 cartridge, since firearms options are so limited — definitely a chicken & egg problem.

One very notable absence from the above discussion is the .22 WMR (.22 Magnum), for the simple reason that we hadn’t tested it yet when I wrote the article. You can find a later article about it here.

Something I didn’t address when I wrote the article initially was ammunition which was formulated to take greater advantage of the longer barrel of a lever gun. Several manufacturers produce such ammo, perhaps most notably Hornady and Buffalo Bore. A blog post which includes the latter ammo out of my 94 Winchester AE can be found here, with subsequent posts here and here.

And lastly, there’s another cartridge we tested which really should be included in the “magnum” category, because it sees the same increasing power levels out to at least 18″ of barrel: .45 Super. This proved to be more than a little surprising, since it is based on the .45 ACP cartridge.  Most semi-auto firearms which shoot the .45 ACP should be able to handle a limited amount of .45 Super, but if you want a lever gun set up to handle the cartridge you’ll have to get it from a gunsmith.

 

Jim Downey

April 2, 2017 Posted by | .22WMR, .32 H&R, .327 Federal Magnum, .357 Magnum, .38 Special, .41 Magnum, .44 Magnum, .45 ACP, .45 Super, .450 SMC, Data, Discussion. | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 3 Comments