Join the party.

All along, we’ve said that if someone wanted to take the time, trouble, and expense to do some additional research along the lines of our protocols, that we’d be happy to include their data on our site. This is particularly true if it helped expand the selection of “real world guns” associated with the data for a given caliber/cartridge. Well, for the first time someone has expressed an interest in doing just that, prompting us to come up with an outline of what standards we feel are required for making sure it relates to our previous tests.

The biggest problem is that ammo manufacturers may, and do, change the performance of their products from time to time. This is why we have on occasion revisited certain cartridges, doing full formal chop tests in order to check how specific lines of ammo have changed. That gives us a benchmark to compare other ammo after a period of several years have passed, and shows how new tests relate to the old data.

But without going to such an extent, how can we be reasonably sure that new data collected by others using their own firearms is useful in comparison to our published data?

After some discussion, we feel that so long as any new testing includes three or more of the specific types of ammo (same manufacturer, same bullet weight & design) we had tested previously, then that will give enough of a benchmark for fair comparison. (Obviously, in instances where we didn’t test that many different types of ammo in a given cartridge, adjustments would need to be made). With that in mind, here are the protocols we would require in order to include new data on our site (with full credit to the persons conducting the tests, of course):

1. Full description and images of the test platform (firearm) used in the tests. This must specify the make, model number, barrel length, and condition of the firearm. Ideally, it will also include the age of the firearm.
2. That a good commercial chronograph be used. Brand isn’t critical — there seems to be sufficient consistency between different models that this isn’t a concern. However, the brand and model should be noted.
3. Chronographs must be positioned approximately 15 feet in front of the muzzle of the firearm used to test the ammo. This is what we started with in our tests, and have maintained as our standard through all the tests.
4. That five or six data points be collected for each type of ammo tested. This can be done the way we did it, shooting three shots through two different chronographs, or by shooting six shots through one chronograph.
5. All data must be documented with images of the raw data sheets. Feel free to use the same template we used in our tests, or come up with your own.
6. Images of each actual box of ammo used in the test must be provided, which show the brand, caliber/cartridge, and bullet weight. Also including manufacturer’s lot number would be preferred, but isn’t always possible.
7. A note about weather conditions at the time of the test and approximate elevation of the test site above sea level should be included.

We hope that this will allow others to help contribute to our published data, while still maintaining confidence in the *value* of that data. Please, if you are interested in conducting your own tests, contact us in advance just so we can go over any questions.

 

Jim Downey

The illusion of precision.

Got an email which is another aspect of the problem I wrote about recently. The author was asking that we get more fine-grained in our data, by making measurements of barrel lengths by one-eighth and one-quarter inch increments. Here’s a couple of relevant excerpts:

what more is really needed, is barrel lengths between 1-7/8 and 4-1/2″.
because of the proliferation of CCW and pocket pistols, and unresolved
questions about short barrel lengths that go all over between 2 and 3.75″,
and snubby revolvers that may be even shorter.

* * *

with that amount of precision, not only would you have data covering all
lengths of short barrels, but you could fabricate mathematical curves that
would predict velocities for any possible barrel length, metric or
otherwise, given the particular ammo.

 

It’s not an unreasonable thought, on the surface. Our data clearly shows that the largest gains in bullet velocity always come in length increases of very short barrels for all cartridges/calibers. So why not document the changes between, say, a 4.48″ barrel and a 4.01″ one? That’s the actual difference between a Glock 17 and a Glock 19, both very popular guns which are in 9mm. Or between a S&W Model 60 with a 2.125″ barrel and a S&W Model 360PD with a 1.875″ barrel?

Ideally, it’d be great to know whether that half or quarter inch difference was really worth it, when taking into consideration all the other factors in choosing a personal defense handgun.

The problem is that there are just too many different variables which factor into trying to get really reliable information on that scale.

Oh, if we wanted to, we could do these kinds of tests, and come up with some precise numbers, and publish those numbers. But it would be the illusion of precision, not actually useful data. That’s because of the limits of what we can accurately measure and trust, as well as the normal variations which occur in the manufacturing process … of the guns tested; of the ammunition used; of the chronograph doing the measurements; even, yes, changes in ambient temperature and barometric pressure.

That’s because while modern manufacturing is generally very, very good, nothing is perfect. Changes in tolerance in making barrels can lead to variation from one gun to the next. Changes in tolerance in measuring the amount of gunpowder which goes into each cartridge (as well as how tight the crimp is, or even tweaks in making the gunpowder itself) mean that no two batches of ammunition are exactly alike. And variations in making chronographs — from the sensors used, to slight differences in positioning, to glitches in the software which operate them — mean that your chronograph and mine might not agree on even the velocity of a bullet they both measure.

All of those little variations add up. Sometimes they will compound a problem in measuring. Sometimes they will cancel one another out. But there’s no way to know which it is.

This is why we’ve always said to consider our data as being indicative, not definitive. Use it to get a general idea of where your given choice of firearm will perform in terms of bullet velocity. Take a look at general performance you can expect from a brand or line of ammunition. Compare how this or that particular cartridge/caliber does versus another one you are considering.

But keep in mind that there’s no one perfect combination. You’re always going to be trading off a bunch of different factors in choosing a self-defense tool.

And never, ever forget that what matters most — FAR AND ABOVE your choice of gun or ammunition — is whether or not you can use your firearm accurately and reliably when you need to. Practice and training matters much more than whether or not you get an extra 25, or 100, or even 500 fps velocity out of whatever bullet is traveling downrange. Because if you can’t reliably hit your target under stress, no amount of muzzle energy is going to do you a damn bit of good.

 

Jim Downey

If you want more information about how accuracy and precision can be problematic, this Wikipedia entry is a good place to start.

Saying farewell to an old friend.

I’ve decided to say farewell to an old friend who has rarely left the safe in the last couple of years.

So if you know anyone who might be interested in a very early (and collectible) Rohrbaugh R9, have ’em take a look at these images and then go on over to Gunbroker (I’ll link to the auction when it is live). I’m selling the gun with all the items shown.

Rohrbaugh R9

Internals

Frame interior

Underside

In custom pocket holster

Holster has a detachable back to mask the shape of the gun

Original case & paperwork, replacement springs, take-down tool set are all included.

As I noted in my review of the R9 from three years back, it’s a fantastic little firearm, and incredibly well made. But as I also noted in that review, I had stopped carrying it much even then. I realized recently that I hadn’t taken it out to shoot for a couple of years. And that just ain’t right.

So I’m going to find it a new home. One where it will be appreciated.

Spread the word. Thanks.

Jim Downey

EDITED TO ADD: Sale concluded happily, and this nice little gun has found a new home. Thanks, everyone!

First date with the Boberg XR9-S.

As I noted a couple of weeks ago, I picked up a ‘little brother‘ for my Boberg XR45-S. Here they are again:

Well, we’re having another delightful warm spell here in mid-Missouri, so yesterday afternoon I took advantage of it and went out to the range to give the little guy a try.

As I noted before, I have actually shot this particular gun a couple of times previously, and just loved it. But it had been a while, and I couldn’t remember specifically what ammo types we had used. So I packed up what variety of 9mm loads I had on hand, along with my chrono, and went to see whether anything had changed.

Because of the way they operate, the Boberg pistols have a tendency to be very particular about what ammo they like. Ammo which doesn’t have a sufficient crimp is prone to separate (the case being jerked away from the bullet). It’s an issue which is well known, and there’s a list of compatible ammo for both the XR9 and the XR45. But while those crowd-sourced lists are useful, the final word is always what specific ammo your particular gun will handle. For me, that’s particularly something I want to determine for any self-defense pistol before I will carry it.

Full details to follow, but for those who just want the short version: oh baby! The XR9 ate everything I fed it without a problem. Including my standard 9mm reloads. No mis-feeds. No bullet separation. No problems. And it was a real joy to shoot, which isn’t something I normally say about a pocket pistol handling full-power SD loads.

OK, for those want the details …

Below are informal* chrono numbers for seven different ammo types I had. These are all for the Boberg. But I also ran a few through my Steyr S9 for comparison, which usually just had an advantage of about 10 fps over the Boberg (the barrel on the Steyr is about a quarter of an inch longer). If that much.

• Buffalo Bore 124gr JHP +P+                                             1,230 fps
• Federal 124gr Hydra Shok JHP                                           1,025 fps
• Reloads. (4.4gr HP-38, 124gr Rainier FMJ bullet)                        1,020 fps
• Remington 124gr FMJ                                                       1,040 fps
• Speer GDHP 115gr JHP                                                      1,210 fps
• Speer GDHP 124gr JHP                                                      1,100 fps
• Speer GDHP 124gr JHP +P ‘Short barrel’                           1,150 fps

As you can see, all pretty respectable numbers. And in keeping with both the claims of the manufacturer as well as what we had tested previously (where there’s overlap). I wouldn’t have any qualms carrying any of the Speer ammo, but my preferred SD ammo is currently the Buffalo Bore. Happily, the Boberg shot all of them without a glitch. And after getting my chrono numbers, I ran several magazines worth through the gun doing some quick shooting at cans, was getting excellent accuracy from it at about 15 yards.

I brought it home, stripped and cleaned it, and now consider it reliable enough to carry. Of course, I will continue to practice with it regularly, and keep a close on on how it performs with my reloads, and occasionally run a mag of carry ammo through it, but I don’t expect any problems. It’s a nice little gun.

Jim Downey

*By ‘informal’, I mean just using one chrono and without the lighting rig we now use for formal testing. And I would just run a magazine of ammo through, mentally noting the numbers in a running tally, then writing them down for that particular ammo, so they are necessarily just ‘ballpark’ figures. But since they jibe well with our previous numbers and what the mfg claims (which I only discovered when I sat down to write this), I think they’re pretty good.

Boberg XR9-S: a new little brother for my XR45-S.

As Frank said on Facebook this afternoon:

I knew when you got the 45 you wanted the 9mm too. It was only a matter of time.

Guilty as charged. Look what followed me home today:

Yup, a Boberg XR9-S: a new little brother for my XR45-S. As I did in that post, I thought I’d put up some comparison pix to give a sense of just how small this gun is, even though it really doesn’t feel like it when you hold it or shoot it.

Here it is again with the XR45:

And here’s the view that shows the thickness of both:

Yeah, there’s a difference. Here’s the XR9 with a Springfield EMP (also 9mm, 3″ barrel – the XR9 has a 3.35″ barrel):

 

And with my J-frame in .38 Special:

For grins, here it is on top of the J-frame:

OK, but how about in comparison to the classic premium pocket 9mm, the Rohrbaugh R9? Here ya go:

The R9 *is* a fantastic little gun, and I love it. I don’t love shooting it, though. The XR9 wins in that category. It will also handle +P ammo and holds one more round (7+1) than the Rohrbaugh. But it is a bit bigger:

Lastly, here it is with a Bond Arms derringer — a great little gun, with a variety of different barrels available. But there’s still just two shots in the derringer, and it actually weighs about 3 ounces more.

While I have shot this gun (it belonged to a good friend), and know it to be dependable, I do still want to make sure that it will be able to reliably digest my preferred SD loads. So more on that to come!

 

Jim Downey

Boberg XR45

I’ve written about the innovative Boberg Arms XR9 previously. Here’s the take-away from my review:

This gun is a winner. It is well designed, and well made. The innovative design makes your brain hurt when you first see it. But the recoil is nothing like what you get from any other “pocket gun”, even when shooting full +P defensive ammunition. Usually with a pocket gun, you trade off the pain of shooting it a lot for the convenience of being able to carry it easily. With the Boberg, you don’t have to make that trade-off. I honestly wouldn’t be bothered at all by running a couple hundred rounds through this gun at the range.

Well, guess what followed me home today.

No, not an XR9. Something a little … bigger:

Yup, one of the new XR45s.

Here’s a pic of one from my outing with the other BBTI guys a few weeks ago:

It’s a little hard to tell how big the gun is in that pic. Here it is with some others:

Starting in the upper left corner and going clockwise, those are: A Steyr S9 in 9mm, a Springfield EMP in 9mm, the Boberg XR45 in .45ACP, and a S&W J-frame in .38sp.

Here’s the Boberg back to back with the Steyr:

With the EMP:

And with the J-frame:

And just for grins, here’s the Boberg with the J-frame sitting right on top of it:

Yeah, the 6+1 Boberg is actually smaller than the three other compact pistols. And it has a longer barrel than all three — 3.75″ on the Boberg, compared to 3.5″ in the Steyr, 3.0″ in the EMP, and 1.875″ on the J-frame.

How does it do this? Because of the innovative … some would say just plain weird … way the feed mechanism works. For the best explanation, take a look at the animation on the Boberg homepage, but basically as the slide comes back, it grabs a new cartridge out of the magazine by the rim and then positions it into the chamber. Yeah, you put the bullets in the magazine nose first. Like this:

And here’s a detail of the top of the loaded mag:

It takes some getting used to, I admit.

Now, while the Boberg is actually smaller in overall size than the other guns, it still has some heft to it: 22 ounces, as opposed to both the Steyr and the EMP at 26. The J-frame shown is a Model M&P 360 with the Scandium frame, so it comes in under 14 ounces. All of those are unloaded weight.

How does it shoot? Like this:

“Not bad at all.”

That was with .45 ACP+P high-end self-defense rounds.

Since I just got mine, it will take a while to find out all the little quirks that it has. But based on shooting one a few weeks ago, and in a much longer session with the 9mm version, I have little doubt that I will be very pleased with it. I’ve already poked around my selection of holsters, and found that the XR45 fits perfectly into a little belt slide holster I have for my Glock 21 Gen 4, as well as into a Mika Pocket Holster I use for the J-frame.

Jim Downey

Six shooter.

Well, well, well, BBTI made it to six years of shooting fun and research!

Yup, six years ago today we posted the first iteration of Ballistics By The Inch, and included data for 13 different handgun cartridges. Since then we’ve continued to expand on that original research, including some extensive testing on how much of an effect the cylinder gap on revolvers has, what performance differences you can expect from polygonal over traditional land & groove rifling, and added another 9 cartridges, as well as going back and including a very large selection of real world guns in all the different cartridges. This blog has had 100,000+ visitors and the BBTI site itself has had something like 25 – 30 million visits (the number is vague because of changes in hosting and record-keeping over time).

We’ve had an impact. I’ve seen incoming links from all around the world, in languages I didn’t even recognize. There’s probably not a single firearms discussion group/blog/site out there which hasn’t mentioned us at some point, and our data is regularly cited in discussions about the trade-offs you make in selecting one cartridge or barrel length over another. I’ve answered countless emails asking about specific points in our data, and have been warmly thanked in return for the work we’ve done. And on more than a few occasions people have pointed out corrections which need to be made, or offered suggestions on how we could improve the site, sometimes providing the results from their own crunching of our data.

When we started, it was fairly unusual to see much solid information on ammo boxes about how the ammunition performed in actual testing. Now that information is common, and expected. Manufacturer websites regularly specify real performance data along with what kind of gun was used for that testing. And the data provided has gotten a lot more … reliable, let’s say. We’ve been contacted by both ammo and firearms manufacturers, who have asked if they can link to our data to support their claims of performance — the answer is always “yes” so long as they make it clear that our data is public and not an endorsement of their product. And we’ve never taken a dime from any of those companies, so we can keep our data unbiased.

And we’re not done. We have specific plans in the works to test at least one more new cartridge (and possibly revisit an old favorite) in 2015. I try to regularly post to the blog additional informal research, as well as sharing some fun shooting and firearms trials/reviews. There’s already been one firearms-related patent issued to a member of the BBTI team, and we’ll likely see several more to come. Because we’re curious guys, and want to share our discoveries and ideas with the world.

So, onward and upward, as the saying goes. Thanks to all who have cited us, written about us, told their friends about us. Thanks to all who have taken the time to write with questions and suggestions. And thanks to all who have donated to help offset the ongoing costs of hosting and testing — it makes a difference, and is appreciated.

 

Jim Downey

Short and fun.

Another quick post about getting together for a bit of shooting weekend before last. This time, let’s look at some semi-auto carbines.

The first two are a pair of Beretta CX4 Storms, one in 9mm and the other in .45ACP. You can see them here with the pump guns:

I’ve previously reviewed the Cx4, and would only add that each time I shoot one of these guns I just enjoy the hell out of them. At just under 30″ overall length and weighing 5.75 pounds, they’re light, easily maneuverable, and very ergonomic. Great little pistol caliber carbines.

Now, see that gun partially visible off to the right in the pic above? And here’s another shot of it with the other pumps and carbines:

See that short little thing third from the left? Yeah, it’s an AGM-1 carbine in 9mm. Here’s a much better pic of it:

It’s an old-school bullpup, made in the 1980s in Italy. None of us had seen one before, and since it was a used gun it came with no paperwork or information. In picking it up, it felt almost too small to be civilian-legal (I mean non-NFA regulated), but the overall length is a tad over 26″ and the barrel is barely 16 and 1/8th inch. It has a little more heft than the Cx4, and most of the parts are heavy stamped steel. It uses Browning Hi-Power magazines. Interestingly, it was intended to be a modular design you could easily convert over to either .22lr or .45ACP, though I doubt the parts to do so are very common now.

But it was a surprisingly nice little gun to shoot. And when I say little, I mean it — damned thing is shorter than my arm. It was accurate, had a nice trigger, and almost no recoil. All of us were able to put a magazine full of bullets into a one-inch hole at 11 yards the first time we picked it up and tried it. Cool gun. If you ever happen to stumble across one in a shop, don’t be afraid to give it a try.

 

Jim Downey

Goodness gracious …

… great balls of fire*:

That’s one of the other BBTI guys shooting a Kel-Tec PMR-30 last weekend.

How was it to shoot?

Actually, pretty nice. Has a surprisingly good trigger. In general, I like Kel-Tec guns for what they are: reasonable quality at a very affordable price. And I downright love my Sub-2000 in 9mm.

But I won’t be getting a PMR-30 anytime soon. Because at the 4.3″ barrel length, it just doesn’t take real advantage of the .22WMR cartridge — you only get about a 20% improvement over a .22lr cartridge.

Unless you like making fireballs.

Jim Downey

*With apologies to Jerry Lee.

Some subgun fun.

Some of the BBTI crew got together this past weekend, mostly for a bit of fun shooting (though we did get to try out some new guns none of us had ever shot before). And I thought I’d share a little bit of the fun here this week with a couple of blog posts.

Let’s start with what we actually finished the day doing on Saturday: two submachine guns.

We were shooting at a a mobile shooting range (which I have written about previously) in Bettendorf, Iowa. It’s a great little range, but forgive the quality of the lighting and noise from the air filtration system in the following two videos:

First, a simple 1960s-era Walther MPL:

And then a *slightly* newer H&K MP5 with a red-dot sight:

Both in 9mm, of course. Here’s a bad pic of them:

And here’s a somewhat better article with some additional pictures and video about the last time I gave them a go: Full Auto.

Oh, and here’s my target after shooting the MP5:

Yup, fun stuff. Please forgive the hoodie — it was COLD in that range!

More later.

Jim Downey

And now for some newer guns.

Last week I posted about some historical reproductions. Now let’s have a quick overview of some newer guns we got to try on the same trip to the range. I’ll include some *very* brief comments, and may return to do longer reviews later when I have some additional time.

First up, the USFA ZiP .22LR, shown with 25-round mag for additional grip purchase:

Comments: Ugh. I hated this gun. Seriously. It’s awkward to hold, worse to shoot, all sharp angles and weirdly thick. It’s the kind of ugly that isn’t even interesting. The design requires you to put your hand right up close to the muzzle to cycle the action. Since it was brand new, I’ll forgive it having problems cycling properly (this is fairly common with rim-fire guns which are brand new), but I sure as hell wouldn’t want to have to shoot it enough to break it in.

Bottom line: if someone insisted on giving me one of these, I’d just turn around and sell it to use the money for almost any other purpose.

 

Next, the Excel Arms MP-22 .22mag Accelerator:

 

 

Comments: Nice gun. Shot very well, and the 8.5″ barrel is sufficiently long to get some benefit out of the .22WMR cartridge.  The heavy bull barrel also does a good job of taming the recoil and muzzle-flip, as can be seen in this vid:

 

Next, the SIG 232 .380acp:

 

 

Comments: SIG SAUER’s version of the classic PPK. Just what you’d expect: quality, accurate, easy to shoot for even someone with large hands, as can be seen in this image of my buddy who has even larger hands than I do:

 

 

Next, the Glock 42 .380acp:

 

 

Comments: I did not expect to like this gun. I was REALLY surprised when I did. Seriously, it is the best-shooting Glock I’ve ever handled. For such a small gun, it fit my large hands comfortably and was easy to shoot well. With Glock quality and reliability, this may be the first .380acp I would seriously consider as a CCW gun.

 

Next, the Kimber Solo Carry 9mm:

 

 

And here’s a vid of shooting it:

 

Comments: Kimber quality. Lot of power in a small package, and I felt it in the web between thumb and forefinger of my dominant hand. But that was just a sting, not uncomfortable, even shooting premium SD ammo. Another good candidate for CCW.

 

And here’s a quick look at an old classic: Winchester Model 70 XTR Featherweight in 6.5 Swedish (6.5mm x 55mm)

 

 

Comments: Like I said, a classic. And as such, a known quantity. But the first time I’ve shot one in 6.5 Swede, and I was pleasantly surprised by how little recoil there was.

Well, that’s all that I have images of, though we also shot a Chiappa M1-22 and a KelTec PMR-30 .22 mag. Again, both are known quantities and shot as expected. Oh, and my buddy gave my Steyr S9 a go, and you can see that vid here.

As noted, I may revisit any of these with a longer review sometime later, but don’t hold your breath.

 

Jim Downey

 

Perceived recoil and bullet weight.

Got a great question recently, and I thought I would share some of my thoughts about it, then invite others to weigh in. Here’s the question:

I hope that you folks can help me with a question I have had for many years now. Why is the recoil so much heavier with lighter bullets in the same caliber and powder loadings than heavier bullets of the same caliber and loadings?

For example. With my S&W model 60, Gold Dot L/E 38 special 135 grain JHP +P loads recoil much harder than the Remington 125 grain JHP +P loads. The same thing happens with my Glock mod 23 .40cal when I shoot 180 grain JHP rounds vs 165 grain JHP rounds. The 165 grain rounds recoil much harder. One would think the heavier round with the same powder load would recoil harder. Can you help?

Perceived recoil is a surprisingly complex problem. It’s not just a matter of total force, but the ‘shape’ of the recoil impulse as well. Then there are the ergonomics of how a particular gun fits a particular person/hand. Add in the mechanical action of how the gun operates (some use part of the recoil energy to cycle the action, some don’t), and various psychological/physiological factors (are you tired? just had an adrenaline dump? afraid of a given gun/caliber/cartridge?), and you can see how many different factors might come into play.

A good place to start is to look at the equation for Muzzle Energy (ME). Let’s use the numbers for the Steyr M40 (very similar to your Glock 23) which was one of the ‘real world’ guns used in the .40 S&W tests we did. Calculations are from Airhog.

The 165gr Federal Hydra-Shok JHP has a velocity of 943fps out of the 4″ barrel. That gives a Muzzle Energy of 325.88ft-lbs.
The 180gr Federal Hydra-Shok JHP has a velocity of 989fps out of the 4″ barrel. That gives a Muzzle Energy of 391.04ft-lbs.

OK, that would seem to indicate that the heavier bullet should cause more recoil. The ME is higher, and you’re shooting them out of the same gun.

But I’m a little wary of that example. Usually, a lighter bullet is faster than a heavier one if they have the similar powder charge, out of barrels of the same length. Here’s another example, looking at 9mm from a Beretta 92.

The Cor-Bon 90gr JHP +P has a velocity of 1522 out of the 4.875″ barrel. That gives a Muzzle Energy of 463.05ft-lbs.
The Cor-Bon 125gr JHP +P has a velocity of 1291 out of the 4.875″ barrel. That gives a Muzzle Energy of 462.72ft-lbs.

And those are very close to the same amount of ME, and should feel about the same in terms of recoil were that the only factor.

So what’s going on? Why do we see one instance where the ammo is just a bit faster in the heavier bullet (resulting in higher ME), but much slower in another instance?

I suspect that it’s probably due to differences in loadings between the different ammo. Even with ammo from the same manufacturer (in the examples above), there’s nothing saying that they are using either the same propellant OR similar amounts of the same propellant for loadings which use different bullet weights. That means that trying to generalize the amount of recoil between different bullet weights just on the basis of brand is difficult if not impossible.

Furthermore, if you’ve done any reloading, or spend some time looking over reloading data, you’ll know that even when you’re using the same propellant in the same cases, different bullet weights usually means different bullets (in terms of manufacturer and/or shape) resulting in different seating depths and overall length. It may seem to be a trivial matter, but this results in different pressure profiles (the amount of pressure within the firing chamber of the gun). Just one example, taken from the Hodgdon Reloading site, for maximum-pressure loads using  GDHPs:

The 90gr bullet with 7.0gr of Longshot powder has an overall length of 1.010″ and gives a velocity of 1,378fps, a pressure of 32,300 PSI, and would have a ME of 379.57ft-lbs.
The 115gr bullet with 6.0gr of Longshot powder has an overall length of 1.125″ and gives a velocity of 1,203fps, a pressure of 32,300 PSI and would have a ME of 369.64ft-lbs.

Note that while the heavier bullet uses a full 1.0gr less of propellant and has a longer overall length, it generates the same amount of pressure. If we drop back to the same amount of the same powder for each loading (6.0gr), then the pressure generated in the lighter bullet loading drops to 29,400 PSI, velocity drops to 1,278fps, and ME drops to 326.48ft-lbs.

But not all pressure is created equal, even if it is nominally ‘the same’. The pressure impulse also matters. That’s the curve of how the pressure rises and falls over time, which is largely related to how ‘fast’ or ‘slow’ the propellant burns. Propellants used for handgun loads tend to be very ‘fast’ (burn rapidly), so the impulse tends to be sharper.  Here’s a good explanation of the matter.

And if you think about it, the heavier the bullet used, the longer/slower it takes to start moving when the cartridge is fired. That should mean that the impulse is spread out over a slightly longer time than it would be with a lighter bullet. So in some sense, the lighter bullet would result with a ‘snappier’ feel. And that may well be what it is that you’re feeling when you experience more perceived recoil (and have controlled for all the other factors) from lighter bullets.

Other thoughts on the subject?

 

Jim Downey

 

 

 

 

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

 

Some Muzzle Energy comparisons.

I got a nice note from Jason at Leaf Technologies, who had been curious about how different cartridges compared in terms of Muzzle Energy (ME). So what he did was take the data from BBTI and average the ME curves for the cartridges he was interested in, then plot them head-to-head in one Excel graph. He sent me the result, and with his permission I am sharing it here:

(Click to enlarge.)

I always love to see how others use our data, and the conclusions they draw from it. It’s EXACTLY the sort of thing we hoped would happen, and why we’ve made the data freely available. If you would like to read some of Jason’s conclusions, and the discussion they engender, pop over to the Northeast Shooters Forum.

And if you have your own interesting spin on how our data can be used in a new way, drop me a note. If I think it’d be of interest to others, I’ll be happy to post it here/link to it. Just send an email to jimd@ballisticsbytheinch.com

 

Jim Downey

Happy Thanksgivuk … er, I mean Birthday!

OK, first: Happy Thanksgiving to all my fellow Americans. And Happy Hanukkah to all who observe it!

But most of all,

Happy Birthday to BBTI!

Yeah, it’s our fifth birthday. We officially launched the site on Thanksgiving in 2008.  And it’s been a fun romp since then. We’ve gone through many different iterations on the site, adding in more calibers/cartridges, doing the big cylinder gap test, tweaking this and changing that. We’ve shot something on the order of 22,000 – 23,000 rounds. We’ve had something in excess of 20 million hits to the site. We’ve invested more than $50,000 and untold hundreds of hours of labor. And we’ve become pretty much the default resource for anyone who has needed (or just wondered about) data pertaining to handgun ammunition performance over barrel length. Like I said, it’s been fun! Thanks for helping to make it so!

And since it is our birthday, it’s time for a gift in the form of a whole new section to the BBTI website:

Polygonal v. Traditional L&G Rifling (“Glock tests”)

From that page:

For years people have wondered about the effects of the different styles of rifling, and whether one or the other would offer specific advantages for accuracy or velocity from a given cartridge.  But since many different factors can have an effect on both accuracy and velocity, these discussions have largely remained anecdotal.  We decided to see whether we could generate data as to performance differences between the two styles of rifling as concerns bullet velocity, using our standard chop-test techniques.  The data on this page is the result of those tests.

Check it out when you get a chance! And thanks again to all who have shared links to our site, who have sent us emails, who have contributed to help offset our costs — you folks have made our success possible, and it is very much appreciated.

 

Jim Downey

PS: as a personal thanks as well, I have made both my first novel and our care-giving memoir available for free download for today and tomorrow (Nov. 28th & 29th).

With charts! Graphs! Slo-mo!

John Ervin at Brass Fetcher Ballistic Testing has put together another great video presentation, showing in several ways how Jacketed Hollow Point (JHP) ammo performs in comparison to Full Metal Jacket (FMJ) ammo for 9 different handgun cartridges. It’s long (22 minutes), but very nicely documents just exactly how the two different bullet styles behave at handgun velocities. Here’s the video:

 

 

The cartridges covered are .22 LR, .25 ACP, .32 ACP, .380 ACP, 9mm Makarov (9×18), 9mm Police (Ultra), .38 Special, 9mm Luger (9×19), and .45 ACP.  His data and presentation makes a great companion to our own data, and I really recommend that you set aside the time to watch the video at your earliest convenience.

 

Jim Downey

How long is too long?

We’ve long known that many pistol calibers/cartridges are optimized for fairly short barrels — you see real benefits in increasing barrel length out to 6″ or 8″ or so, with diminishing returns beyond that. (The exception to this is the ‘magnum’ rounds: .44mag, .357mag, etc.) It’s not that you don’t see any benefit in a longer barrel, but the gain tends to flatten out. Take a look at the muzzle energy graph for the 9mm Luger (9×19) and this is quickly apparent:

Take a look at the left side of that graph. There’s some indication that the bullets are actually slowing down in the last couple of inches of an 18″ barrel. Whether or not this is just a glitch in our earlier test data, or an indication that friction is starting to win out over the remaining energy from the expanding gas of a fired cartridge is something I’ve always wondered about. Clearly, at some point a bullet will start to slow down, even stop; anyone who has ever fired a squib load and had to hammer the bullet out of a barrel knows that this can indeed happen. But at what point would this effect start to be clear?

Good question. And not one we really wanted to spend the money on to find out. See, the barrel blanks we’ve used all along came in an 18″ length standard for pistol calibers/cartridges. Longer barrels were available from different sources, but there was a big jump up in price for those, and it just didn’t make much sense to get into that.

However …

When we started to set up to do the so-called “Glock Tests” we had to find a different source for our barrel blanks, since our other supplier couldn’t provide a polygonal barrel (the kind of barrel Glock uses, though they are not unique in this). We sourced the barrels from Lothar Walther. And as it turned out, their barrel blanks are longer than 18″. Specifically, we received a 26″ barrel with traditional land-and-groove rifling and a 24″ barrel with polygonal rifling. Here they are:

9mm barrel blanks

So …

Well, we didn’t want to spend the time and money doing full chop tests from 26/24 inches down to 18″. But we did decide to just go ahead and get some benchmark data at the full length, just for shits and grins. And here is the data for those lengths, along with data from 18″, 17″, and 16″ lengths for comparison:

PNW Arms STD P 115gr SCHP

Trad:    1074 fps     1161 fps     1163 fps     1171 fps
Poly:    1064 fps     1131 fps     1131 fps     1135 fps

Federal STD P 115gr Hi-Shok

Trad:     1305 fps     1330 fps     1333 fps     1330 fps
Poly:     1323 fps     1331 fps     1336 fps     1135 fps

CorBon +P 115gr DPX

Trad:     1117 fps     1232 fps     1249 fps     1236 fps
Poly:     1057 fps     1186 fps     1195 fps     1208 fps

Black Hills +P 115gr JHP

Trad:     1494 fps     1508 fps     1512 fps     1498 fps
Poly:     1496 fps     1521 fps     1515 fps     1518 fps

Federal STD P 147gr JHP

Trad:     1036 fps     1061 fps     1084 fps     1085 fps
Poly:     1046 fps     1088 fps     1098 fps     1088 fps

So, there ya go: in each and every case, there is a noticeable decrease in velocity in going from an 18″ barrel to either the 24″ or 26″ barrel. And keep in mind that the protocols for this test were 10 shots of each ammo at each barrel length over two chrono units, rather than just 3 shots as we had done for previous chop tests.

Not too surprising, but nice to see actual data.

We hope to have the full data sets, with charts & graphs, up on the website soonish (maybe next week?). Watch here and on our FaceBook page for a posting when it is available.

 

Jim Downey

M1 .30 carbine performance.

Got another nice email with a video link from John Ervin at Brass Fetcher Ballistic Testing, this time covering the performance of the venerable M1 Carbine .30 cal cartridge. From John:

Despite its handsome wood furniture and vaguely military-type appearance, the M1 Carbine is an effective firearm for self-defense and small game hunting.  Hornady makes ‘Critical Defense’ ammunition for it now and Federal continues to make its excellent 110gr SP, so good ammunition choices are available for M1 Carbine owners.

The M1 Carbine is excellent for its low recoil, small mechanical sight offset and cartridge that is sufficient in lethality to repulse human attackers (when using good soft point ammunition) at distance.

And here’s the video so you can see for yourself:

 

 

I’ll leave it at that for now … I have a lot to do this week to get ready for our 9mm “Glock Tests” this coming weekend. Yup, those are finally happening. I’ll post some preliminary thoughts/results probably this weekend or the first of next week, with full info to come after we have a chance to crunch the numbers a bit.

 

Jim Downey

Ammo shortage? What ammo shortage??

Oh — THAT — ammo shortage.

Yeah, the beginning of January I wrote that we were finally moving forward with the testing of polygonal vs. traditional rifling; the so-called “Glock Tests“, and outlined how we were planning on conducting a bit of an experiment in asking for suggested ammo loads to include in the tests, and then seeing what kind of support there was for a slate of different choices by allowing pledges to help purchase ammo.

But, as someone who wrote me put it: where did we think we were going to *find* any such ammo?

Initially, I thought that the shortage we were seeing would be a fairly temporary problem, and that by the time spring rolled around we’d be able to locate sufficient quantities for our testing (we need about 350 rounds of each type).

Yeah, so much for that idea. Now you know why I don’t play the stock market or bet on races.

The ammo shortage has just continued to deepen. It’s to the point where people are having a hard time finding enough of any kind of ammo just to keep in practice with a trip to the range once or twice a month.  I’m damned glad I reload my practice ammo, and have a decent store of most components.

But that doesn’t do a damned thing for our testing. The whole idea is to test factory ammo, not some cobbled-together handload version of factory ammo.

So we’re putting off the “Glock Tests” again, until the situation gets better. Keep an eye here and elsewhere for news about when this will change.

One good bit of news, however: we already had a decent selection and sufficient quantity of each ammo type to do the .22WMR (.22Magnum) tests.  So we’re going to go ahead and do that sequence of tests here this spring — sometime soon!

Sorry for the bad news, everyone — really. These tests have been delayed several times for one (good) reason or another, and we’re just as frustrated by that as everyone else.  But when ammo supplies start to become more available, we’ll be sure to try and get them done as soon as we can.

Cheers!

Jim Downey

Now, about those “Glock” tests…

As mentioned previously, for some time we’ve been planning on doing a series of inch-by-inch chop tests on the Glock-style polygonal barrels  (Glock was unable to supply 18″ barrels, so we’ll be using 6 grove poly and 6 land traditional barrels from Lothar Walther).  We’ve run into a number of unexpected delays, but now have the barrels we need, and are planning on doing the series of tests sometime later this year, hopefully in spring/early summer. For testing purposes, we’ll be conducting traditional ‘land & groove’ barrels in the same calibers at the same time, so that we have direct head-to-head comparisons. Because we’re expecting a fairly subtle difference in performance, we’re going to do 10 (ten) shots for each inch of barrel for both style barrels. And to keep the scope of the project manageable, we’re only going to test two cartridges/calibers: 9mm (9×19) and .45 ACP.

In order to do the tests this way, we’ll need a minimum of 340 rounds of each ammo to test. Add in “real world guns” and allowing for errors/glitches which mean extra shots, we’re planning on getting 400 rounds of each ammo to be tested. Figure an average of about $1 per round for premium self-defense ammunition, and we’re looking at about $400 for each ammo selected for testing. There are some specific ammunition types/loads we’ve tested previously that we want to revisit for comparison purposes, but our selection is hardly comprehensive — time and money are limited.

So we’d like to try an experiment: do Kickstarter-style crowdfunding to see what ammunition types/loads people want to have us test. This will allow two things:

1. To let people help support the project by offsetting our costs.
2. To help us find new ammunition types/loads.

Now, Kickstarter itself isn’t firearm-friendly. And that’s OK — we can do this on our own, just using our own site. What we’ll do is put up a list of different ammo types/loads, and solicit donations targeted for each during a specific time frame. When pledges are made, we’ll keep a running tally total for each ammo, and once it crosses a certain threshold, then that specific type/load will be added to our testing list.

But first we need to create our list of ammo. So, for the next two weeks, either add a comment to this blog post or send an email to info@ballisticsbytheinch.com with one specific 9mm ammunition type/load you would like to see us test. Please, just one type/load per comment or email, and just five or six such entries per person. I’m going to have to collate these myself, so help make it a little easier on me. Just sending in a selected ammo doesn’t obligate you to support that ammo with $ in the second phase of this test, but it’s probably a good idea to only recommend ammo you would be willing to actually support, and ones you think you can get others to support. And remember, keep your recommendations limited to factory mass-produced ammo; handloads or artisanal ammo which the average person doesn’t have access to will not be selected for inclusion in the tests. Also: we’re only accepting recommendations and donations from individuals, not ammo manufacturers.

You can see all the 9mm ammo we’ve tested previously here: 9mm Luger Results.

As I said, this is an experiment. If it works for selecting 9mm ammo to test, we may extend it to the .45 ACP tests, and then see about using a similar approach for other testing. We hope that this will be a way we can expand our research and make it more responsive to what data the firearms-enthusiast community wants to see. You can help by sending in your suggestions, but in also spreading the word on the different forums/blogs where our data may be used.

Thanks, everyone, for your ongoing interest and support!

Jim Downey