Ballistics by the inch

2016 in the rear-view mirror.

Happy New Year!

A quick recap of the last year: surprisingly active.

It’s interesting to see how things have evolved with BBTI over time. The last test sequence we did was the .45 Super /.450 SMC tests, with the data published in October 2015. So without new test results last year, we didn’t have the usual big spike in site visits. But we still saw a total of 447,203 visitors last year, which ain’t too shabby.

And last year we saw an evolution in who were our biggest referrers, as well. Excluding search engines, here they are in order:

  1. DefensiveCarry.com
  2. Guns.com
  3. MechTech Systems
  4. Wikipedia
  5. The Firearm Blog
  6. reddit
  7. Active Response Training
  8. Survivalist Boards
  9. The Firing Line
  10. AR15.com

All but four (Guns.com, MechTech Systems, Wikipedia, and The Firearm Blog) are discussion forums, and of those four The Firearm Blog also has a very active discussion community. MechTech Systems sells conversion kits for pistols, allowing you to turn your pistol into a carbine, so it makes perfect sense that they would link to us showing the advantage you can gain with a longer barrel.

In other words, most of the referrers are places where BBTI is being cited as a reference to help people make decisions about their firearm choices. That just makes sense, and corresponds to the email we get, thanking us for our site or asking for clarification/recommending new ammo to test. After 8 years, and with no new tests, there’s not much reason for the ‘news’ sites to mention us — but there’s still plenty of interest in the firearms community in the data we provide.

So thanks to all who share our site with others! You’re the real reason our site is a success!

 

Jim Downey

 

January 1, 2017 Posted by | .45 Super, .450 SMC, Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Effective shotgun ranges.

One of the questions we get regularly is asking whether we’re going to do some velocity/chop tests on shotguns. For a variety of reasons (both logistical & legal) we’ve decided that such tests are beyond the scope of what we want to tackle.

But that doesn’t mean that it’s not something of interest to us, collectively and individually. I’ve previously posted about tests which John Ervin at Brassfetcher has conducted showing the effectiveness of buckshot at 50 yards. And from personal experience, I knew that slugs from a 12 gauge are effective for hunting (or self defense) out to 100 yards, depending on the skill of the shooter.

But how about slugs at 200 yards? And how about DIY ‘cut shells’, which mimic slugs? And, say, if you did happen to hit a target at 100 yards with buckshot, would it be lethal?

Via The Firearm Blog, this video explores all these questions, and provides some VERY interesting answers:

It’s well worth the time to watch the whole thing. But the bottom line is that 00 Buckshot pellets would still be lethal at 100 yards, if you could connect with your target. And slugs? Easily to 200 yards, with a fair amount of control on hitting your target. At 300 yards, they’re still effective, but the trajectory is such that it’s much more difficult to reliably hit the target. And at 400 yards … well, watch to video to see for yourself.

Kudos to Iraqveteran8888 for conducting some really solid and informative tests, and sharing that information with the public.

 

Jim Downey

July 16, 2016 Posted by | Anecdotes, Data, Discussion., Links, Shotgun ballistics | , , , , , , , , , , , , , , , , , , , | Leave a comment

Velocity is great, but mass penetrates.

OK, kiddies, it’s time for SCIENCE!

Ballistic science, specifically. I promise to keep the math to a minimum, because I don’t like it much, either. Jim Kasper is the one who thinks in terms of equations, not me.

If you look at any of the various pages for test results on BBTI you will see that each caliber/cartridge also has a link for a Muzzle Energy (the kinetic energy of a bullet as it leaves the muzzle of a gun) graph for that set of results. That’s because Muzzle Energy can also give an idea of the effectiveness of a given ammo, since it is a calculation of both the weight of a bullet as well as the velocity it is traveling. This calculation, specifically:

E_\text{k} =\tfrac{1}{2} mv^2

Here’s what that says in English, taken from the explanation that goes with that image on Wikipedia:

The kinetic energy is equal to 1/2 the product of the mass and the square of the speed.

In other words, you multiply the weight of the bullet times the square of the velocity, then take half of whatever number you get. And that gives you the Muzzle Energy, usually (as on our site) expressed in foot-pounds of energy.

So there are two ways you can change the result: change the amount of weight, or change the amount of velocity.

But since it is the square of the velocity (the velocity times itself), changes to the velocity have a larger impact on the final amount of Muzzle Energy. That’s the reason why how the velocity changes due to barrel length is such a big deal, and why we’ve done all the research that we’ve done over the last seven years.

But while Muzzle Energy gives you a good way to compare the power and potential effectiveness of a given cartridge as a self-defense round, there are a couple of other factors to consider. A couple of VERY important factors.

One is the shape and composition of the bullet itself. There’s a very good (surprisingly good, in fact — I heartily recommend you read the whole thing) discussion of the basic shapes and how they interact with the human body in this online teaching tool intended for medical students. The relevant excerpt:

Designing a bullet for efficient transfer of energy to a particular target is not straightforward, for targets differ. To penetrate the thick hide and tough bone of an elephant, the bullet must be pointed, of small diameter, and durable enough to resist disintegration. However, such a bullet would penetrate most human tissues like a spear, doing little more damage than a knife wound. A bullet designed to damage human tissues would need some sort of “brakes” so that all the KE was transmitted to the target.

It is easier to design features that aid deceleration of a larger, slower moving bullet in tissues than a small, high velocity bullet. Such measures include shape modifications like round (round nose), flattened (wadcutter), or cupped (hollowpoint) bullet nose. Round nose bullets provide the least braking, are usually jacketed, and are useful mostly in low velocity handguns. The wadcutter design provides the most braking from shape alone, is not jacketed, and is used in low velocity handguns (often for target practice). A semi-wadcutter design is intermediate between the round nose and wadcutter and is useful at medium velocity. Hollowpoint bullet design facilitates turning the bullet “inside out” and flattening the front, referred to as “expansion.” Expansion reliably occurs only at velocities exceeding 1200 fps, so is suited only to the highest velocity handguns.

Now, while that last bit about needing to exceed 1200 fps may have been true, or a ‘good enough’ approximation a few years ago, it isn’t entirely true today. There has been a significant improvement in bullet design in the last two decades (and these innovations continue at a rapid pace), so that there are now plenty of handgun loads available which will reliably expand as intended in the velocity range expected from the round.

The other REALLY important consideration in bullet effectiveness is penetration. This is so important, in fact, that it is the major criteria used by the FBI and others in assessing performance. From Wikipedia:

According to Dr. Martin Fackler and the International Wound Ballistics Association (IWBA), between 12.5 and 14 inches (318 and 356 mm) of penetration in calibrated tissue simulant is optimal performance for a bullet which is meant to be used defensively, against a human adversary. They also believe that penetration is one of the most important factors when choosing a bullet (and that the number one factor is shot placement). If the bullet penetrates less than their guidelines, it is inadequate, and if it penetrates more, it is still satisfactory though not optimal. The FBI’s penetration requirement is very similar at 12 to 18 inches (305 to 457 mm).

A penetration depth of 12.5 to 14 inches (318 and 356 mm) may seem excessive, but a bullet sheds velocity—and crushes a narrower hole—as it penetrates deeper, while losing velocity, so the bullet might be crushing a very small amount of tissue (simulating an “ice pick” injury) during its last two or three inches of travel, giving only between 9.5 and 12 inches of effective wide-area penetration.

As noted above, the design of the bullet can have a substantial effect on how well it penetrates. But another big factor is the weight, or mass, of the bullet relative to its cross-section — this is called ‘sectional density‘. Simply put, a bullet with a large cross-section and high mass will penetrate more than a bullet with the same cross-section but low mass moving at the same speed. It isn’t penetration, but think of how hard a baseball hits versus a whiffleball moving at the same speed. They’re basically the same size, but the mass is what makes a big difference. (See also ‘ballistic coefficient‘).

With me so far?

OK, let’s go all the way back up to the top where I discussed Muzzle Energy. See the equation? Right. Let’s use the baseball/whiffleball analogy again. Let’s say that the baseball weighs 5.0 ounces, which is 2,187.5 grains. And the whiffleball weighs 2/3 of an ounce, or 291.8 grains. A pitcher can throw either ball at say 60 mph, which is 88 fps. That means (using this calculator) that the Kinetic Energy of a baseball when it leaves the pitcher’s hand is  37 foot-pounds, and the whiffleball is just 5 foot-pounds. Got that?

But let’s say that because it is so light, the pitcher can throw the wiffleball twice as fast as he can throw a baseball. That now boosts the Kinetic Energy of the whiffleball to 20 foot-pounds.

And if you triple the velocity of the whiffleball? That gives it a Kinetic Energy of 45 foot-pounds. Yeah, more than the baseball traveling at 88 fps.

OK then.

Now let’s go look at our most recent .45 ACP tests. And in particular, the Muzzle Energy graph for those tests:

What is the top line on that graph? Yeah, Liberty Civil Defense +P 78 gr JHP.  It has almost 861 foot-pounds of energy, which is more than any other round included in those tests. By the Muzzle Energy measure, this is clearly the superior round.

But would it penetrate enough?

Maybe. Brass Fetcher doesn’t list the Liberty Civil Defense +P 78 gr JHP. But they did test a 90 gr RBCD round, which penetrated to 12.0″ and only expanded by 0.269 square inch. Compare that to the other bullets listed on his page, and you’ll see that while the depth of penetration isn’t too bad when compared to other, heavier, bullets, that round is tied with one other for the least amount of expansion.

Driving a lightweight bullet much, much faster makes the Muzzle Energy look very impressive. Just the velocity of the Liberty Civil Defense +P 78 gr JHP is impressive — 1865 fps out of a 5″ barrel is at least 50% faster than any other round on our test results page, and almost 400 fps faster than even the hottest of the .45 Super loads tested.

But how well would it actually penetrate? Without formally testing it, we can’t say for sure. But I am skeptical. I’m not going to volunteer to getting shot with one of the things (or even hit with a whiffleball traveling 180 mph), but I’m also not going to rely on it to work as it has to in the real world, where deep penetration is critical. I want a bullet with enough punch to get through a light barrier, if necessary. Like this video from Hickok45, via The Firearm Blog:

Personally, I prefer a heavier bullet. Ideally, I want one which is also going to have a fair amount of velocity behind it (which is why I have adapted my .45s to handle the .45 Super). All things being equal (sectional density, bullet configuration and composition), velocity is great, but mass is what penetrates.

Jim Downey

November 8, 2015 Posted by | .45 ACP, Data, Discussion. | , , , , , , , , , , , , , , , , , , , , , , , , , , , | 3 Comments

No matter which way you look …

…whether back over 2014, or forward into 2015, things are pretty good vis-a-vis BBTI.

Yeah, 2014 was pretty good. We didn’t do any formal testing, though I did some informal testing and a fair number of reviews of new guns or guns which were just new to me.  Having the chance to do those now and again is enjoyable, without having the same deadline pressures I had when I was doing regular columns and reviews for Guns.com.

The numbers also look pretty good for 2014. This blog went from about 12,000 visits in 2013 to 22,000 last year – nearly double. And the BBTI site itself jumped from 243,230 visitors in 2013 to 318,304 visitors in 2014 — an increase of about a third. Visits have also continued to climb pretty steadily from day-to-day, with typically about 1,250 or so daily by the end of the year. Given that we didn’t do any new testing, that’s pretty impressive.

And of course, we’d like to thank all who linked to us over the past year. Here’s the top ten referring sites for 2014, excluding search engines and Wikipedia:

  1. thefiringline.com
  2. defensivecarry.com
  3. guns.com
  4. thefirearmblog.com
  5. ar15.com
  6. gunsamerica.com
  7. reddit.com
  8. thetruthaboutguns.com
  9. rimfirecentral.com
  10. survivalistboards.com

How about the year to come, then?

Well, we’re planning on doing one largish series of tests, to cover .45 Super, .450 SMC, and a number of additional .45 ACP loadings. We haven’t yet set a date for this sequence, but I will post a note about it here and on our Facebook page once plans solidify.

And behind the scenes, improvements continue at the BBTI website. We recently upgraded our hosting set-up, to shift over to more modern software technology. We’ve started discussing how we can do better presentations of our graphs and spreadsheets. I would still very much like to work with someone to develop a mobile app — if you have the necessary skill set to do that, please drop me a note. And whenever someone finds a glitch in our data or how the site renders for them, we try and make the corrections. None of this is very obvious, but it is all a lot of work, and I’d like to once again thank our web guru (and my lovely wife) at Coeurbois Graphic Design for her efforts.

Lastly, thanks to all who use the site regularly, who cite us in online discussions, who help to spread the word. And especially, I would like to thank all who have donated to BBTI in the last year — your tangible contributions make a difference, and help to offset our ongoing costs.

Happy New Year!

 

Jim Downey

January 2, 2015 Posted by | .45 ACP, .45 Super, .450 SMC, Boberg Arms, Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment

Wait … it’s 2014?? How did THAT happen?

2013 was a busy year for BBTI.

We did the .22Mag tests. We did the 9mm Glock Tests. I got my .460 Rowland conversion up and running. And I found some really fun .44Mag +P+ loads, then figured out a simple hack so that they would feed reliably in my lever gun. Like I said, a busy year.

And we couldn’t have done it without help. Of several types. To see the list of those donors who have helped offset some of our operating costs, pop over to the BBTI site. And here’s a list of the top-10 referring sites (excluding search engines and Wikipedia):

  1. thefiringline.com
  2. defensivecarry.com
  3. guns.com
  4. thefirearmblog.com
  5. ar15.com
  6. thetruthaboutguns.com
  7. survivalistboards.com
  8. glocktalk.com
  9. reddit.com
  10. rimfirecentral.com

Altogether, we had 243,230 visitors to the BBTI website, and some 12,000+ views of this blog. Since we’ve gone through several iterations of the site over the last five years, it’s hard to say exactly how many visitors or pageviews or hits we’ve had in total — but it’s more than we ever really expected. Thanks, everyone.

And particular thanks to my Good Lady Wife, who has done all the webwork and most of the number crunching over the years.

We don’t currently have any concrete plans for new tests in 2014. But who knows? Keep an eye here and on our Facebook page for news.

Happy New Year, everyone!

 

Jim Downey

 

January 1, 2014 Posted by | .22WMR, .44 Magnum, .460 Rowland, 9mm Luger (9x19), Anecdotes, Data, Discussion., Links | , , , , , , , , , , , , , , , , , | 3 Comments

Just take a little off the sides, leave the top alone.

So, yesterday was our best day ever for this blog, doing 50% more traffic than any previous day. Why? Well, thanks to a link from The Firearm Blog about my experiments to alter the Buffalo Bore 340gr .44mag loads I’ve written about recently. So I wanted to say thanks to Steve over there, and to all his readers.

And I also wanted to report how the rounds behaved after a trip to the range this morning. I think pictures tell the story just fine. Here’s the first one:

20130829_105140

That’s a 3″ circle, just for reference. Those are three shots, fired from a sitting position at 50 yards (well, paces, so something pretty close to 50 yards). That’s with the standard, unaltered, 340gr rounds from my Winchester 94AE which has the standard iron sights. I wasn’t trying for super accuracy, just the sort of quick sight and shoot you’d do when hunting at that range. It may be worth noting that I had to hand-feed each round into the chamber of the gun, since these unaltered cartridges will not feed from the tube magazine. If you look close, you’ll see that I marked through each hole with a blue Sharpie.

Here’s the second picture:

20130829_105528

Exact same parameters as the first pic, but this time with three rounds which had been shaved as discussed in the previous posts. And since these rounds will reliably feed from the tube magazine, they were shot then the gun was cycled and then the next shot taken in fairly quick sequence. For clarity, I marked through the second set with a red Sharpie.

My conclusion? They’re as accurate as the unaltered cartridges. Which is to say, within the limits of my ability using them like that. With a good shooting rest and a scope you might be able to tell a difference, particularly at greater range. But for what I wanted them for, they’re entirely suitable. YMMV.

 

Jim Downey

August 29, 2013 Posted by | .44 Magnum, Anecdotes, Data, Discussion., Links | , , , , , , , , , , , , | Leave a comment