Ballistics by the inch

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

November 28, 2014 Posted by | .22, .223, .22WMR, .25 ACP, .30 carbine, .32 ACP, .32 H&R, .327 Federal Magnum, .357 Magnum, .357 SIG, .38 Special, .380 ACP, .40 S&W, .41 Magnum, .44 Magnum, .44 Special, .45 ACP, .45 Colt, .460 Rowland, 10mm, 6.5 Swedish, 9mm Luger (9x19), 9mm Mak, 9mm Ultra, Anecdotes, Data, Discussion., General Procedures, Links, Shotgun ballistics | , , , , , , , , , , , , , , , , , , , , , | Leave a comment

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





June 15, 2014 Posted by | .38 Special, 9mm Luger (9x19), .40 S&W, Data, Discussion., Links | , , , , , , , , , , , , , , , | Leave a comment

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


Jim Downey

December 12, 2013 Posted by | .357 Magnum, .357 SIG, .380 ACP, .40 S&W, .45 ACP, 10mm, 9mm Luger (9x19), Data, Discussion., Links | 1 Comment

Last chance.

So, we have a new winner! Kyle won the all-leather IWB of unknown make.

The next, and final, holster in our drawing is very much a known brand: a High Noon Holsters “Skin Tite” model leather OWB. This is a right-handed almost new holster which has a $54.95 value (plus shipping).

This particular holster is marked for a Steyr M. But just about any medium-large semi will fit (though the retention snap may not be in the perfect position). Interestingly, both a full-size 1911 and my Ruger Mark I fit perfectly (with the barrel protruding out the bottom).

Rules are the same as previously:

So, here’s the deal: make any kind of contribution to the Kickstarter (as little as $1.00 – I won’t mind), and enter into this drawing for a holster. Please note that this is *IN ADDITION* to the other rewards there on the Kickstarter – all perfectly good and valuable rewards. Then just come here and leave a comment, or post it on the BBTI Facebook page, or send me a Tweet. I’ll enter your name into a completely separate drawing. And next Wednesday after the Kickstarter is over I’ll select a name and send that person this holster is up for grabs.

If you’ve already contributed to the Kickstarter, just let me know and your name will go in the hat for this drawing.

Last chance – get your entries in and help me out with making the Kickstarter a success! Thanks!

Jim Downey

October 12, 2012 Posted by | .22, .357 SIG, .40 S&W, .45 ACP, .460 Rowland, 10mm, 9mm Luger (9x19), 9mm Mak, 9mm Ultra, Discussion., Links | Leave a comment

It’s Up!

The new Ballistics By The Inch site is now up and running! Bigger, Faster, And with More DATA! Take a look, spread the word, let us know if there are any glitches or problems.

Jim Downey

December 1, 2011 Posted by | .22, .223, .25 ACP, .32 ACP, .32 H&R, .327 Federal Magnum, .357 Magnum, .357 SIG, .38 Special, .380 ACP, .40 S&W, .41 Magnum, .44 Magnum, .44 Special, .45 ACP, .45 Colt, .460 Rowland, 10mm, 9mm Luger (9x19), 9mm Mak, 9mm Ultra, Anecdotes, Data, Discussion., General Procedures, Links | , , , , | Leave a comment

Wiki, oh Wiki, where do you roam?

Just spent a chunk of the afternoon and early evening doing something I had been meaning to do for at least a year: adding info about BBTI to various and sundry Wikipedia pages about ballistics and cartridges. I still need to create an actual ‘page’ about BBTI, but haven’t ever done that, so . . .

Anyway, now for all the cartridges/calibers we tested there are links on Wikipedia, plus any related entries that I could think of. But if you find yourself poking around there, and come across an entry which would appropriately link/mention BBTI, please edit it to do so (or drop me a note and I’ll take care of it.) This isn’t an effort to get more hits to the BBTI site (we’re rapidly approaching 2.5 million), but just to help more people get the information that they need.

Jim Downey

April 30, 2010 Posted by | .25 ACP, .32 ACP, .32 H&R, .327 Federal Magnum, .357 Magnum, .357 SIG, .38 Special, .380 ACP, .40 S&W, .41 Magnum, .44 Magnum, .44 Special, .45 ACP, .45 Colt, 10mm, 9mm Luger (9x19), Data, Discussion., Links, Uncategorized | 2 Comments

Making us safer . . .

. . . by losing their guns?

Report: Officers lose 243 Homeland Security guns

Washington (CNN) — Nearly 180 Department of Homeland Security weapons were lost — some falling into the hands of criminals — after officers left them in restrooms, vehicles and other public places, according to an inspector general report.

The officers, with Customs and Border Patrol and Immigration and Customs Enforcement, “did not always sufficiently safeguard their firearms and, as a result, lost a significant number of firearms” between fiscal year 2006 and fiscal year 2008, the report said.


And yet, one of the most common responses I hear to the idea of private citizens exercising our 2nd Amendment rights is that only law enforcement officers are trained adequately to safely handle and carry firearms.

Like this guy, no doubt:


Jim Downey

(Cross posted to my blog.)

February 19, 2010 Posted by | .40 S&W, Anecdotes | Leave a comment

I love it.

I mentioned the other day that the BBTI site was closing in on 2 million hits. And, with the site chugging along with 3,500 – 4,500 hits a day, I figured we’d get there before the end of this month. But then, over the last couple of days, hits about doubled, approaching 7,000 hits a day.

Now, this happens. Usually it is due to BBTI being “discovered” and posted on a new gun/shooting forum someplace – so a bunch of people who haven’t heard about the project yet run off to check it out, and send links to their friends. And it has also happened when I’ve posted some new information to the site (such as when we added in the additional testing results last spring) or announce something new in the works (as with the cylinder gap tests).

But that wasn’t the reason why we saw the bump up this time. Instead, it was because of an announcement from the FBI.

See, the FBI has announced that they are going to go to a .40 S&W AR-15 carbine. And in discussing that decision, people started citing our numbers on the .40 S&W cartridge performance in different barrel lengths. You can see what I mean at The Firearm Blog, at Calguns, and elsewhere. This is something I have mentioned before, how BBTI has come to be increasingly used as a resource for evaluating firearm performance, but this is the first time that I’ve seen it happen in response to some newsworthy item. And I think that is really pretty cool.

Jim Downey

(Cross posted to my personal blog.)

February 9, 2010 Posted by | .40 S&W, Data, Discussion., Links | Leave a comment

Closing in on a million.

Just under a month ago I wrote about launching the major upgrade to BBTI. Since then, we’ve had 217,390 hits to the site, bringing us to just shy of one million hits (986,999) as of midnight. Given how things have been going the last couple of days, I expect we’ll break a million today or tomorrow. [edited to add: we had over 21 thousand hits on 6/27, thereby crossing a million.]

And that’s kinda cool.

So, thanks to all who passed along word of our project. In particularly, our top ten referrers have been:


I find it interesting that the top referrer (by a long shot) isn’t even a firearms-related site. That we’ve risen high in Google searches comes as very little surprise, and I’m pleased that the BBTI blog itself has such a prominent spot, just after five of the best known gun forums/blogs. That’s kinda cool, too.

Anyway, thought I would pass this bit of good news along.

Jim Downey

(Cross posted to my personal blog.)

June 27, 2009 Posted by | .25 ACP, .32 ACP, .32 H&R, .327 Federal Magnum, .357 Magnum, .357 SIG, .38 Special, .380 ACP, .40 S&W, .41 Magnum, .44 Magnum, .44 Special, .45 ACP, .45 Colt, 10mm, 9mm Luger (9x19), Data, Links | 1 Comment

Six months ago.

Six months ago we launched Ballistics By The Inch. And since then we’ve had over 770,000 hits, one major magazine article, and coverage & discussion of the site in countless gun forums & blogs around the globe. When I have checked the stats for the site, I have never failed to be impressed with just how widely it has become known.

Well, tonight we posted a major upgrade to the whole site. This includes three additional caliber ‘chop tests’, but it also includes data collected from testing over 40 additional “real world” guns – including a baker’s dozen carbine-length guns. This data has been separated out into a new series of graphs for easy comparison. All together, there are now over 150 graphs showing ballistic performance – along with all the charts giving numerical averages for each 1″ increment in barrel length for 16 different calibers. And for the true data junkies, there are downloadable files (in two formats) for the entire sequence of initial tests, and another set for the second round of testing done in April 2009.

Like the initial project, this major upgrade and revision has been a huge job – and one only made possible by a lot of work from several individuals. Yes, there were the three of us testers from the original project. But there was also the addition of a fourth tester this time around who helped us gather & operate all those ‘real world’ guns, and I would like to welcome Keith to our team. But I would especially like to thank my good lady wife for all the html coding & design for our website – both the last time and with this major revision. Quite literally, none of this would have been available without her hard work.

There will probably be minor tweaks and additions to the site in the coming months and years. We still have some ideas of data which might be of interest to the gun community. But for now we hope that you will enjoy and make use of the data provided, and help to spread the word to others who may be interested.


Jim Downey

(Cross posted to my personal blog.)

May 28, 2009 Posted by | .25 ACP, .32 ACP, .32 H&R, .380 ACP, .38 Special, 9mm Luger (9x19), .357 SIG, .357 Magnum, .40 S&W, .44 Special, .44 Magnum, .45 ACP, .45 Colt, Data, .327 Federal Magnum, .41 Magnum, 10mm | 3 Comments

The big list.

When we did the original round of tests, we used one or two ‘real world’ pistols for each caliber as a reference point for people to compare to the ideal platform of the T/C Encore. We thought that this would be adequate. But it quickly became evident that a lot of people wanted more data points of how ‘real world’ guns would compare at different barrel lengths.

So one of the major goals of this most recent round of testing was to revisit those calibers we had tested last year using a lot more ‘real world’ guns. In preparation for the testing, we started asking around from friends and family, until we had over 40 additional guns to test, in different lengths and quality. Here is that list:

Para LDA Carry 9 – 9mm, 3” barrel
Korth semi-auto – 9mm, 5″ barrel
Beretta 92 FS – 9mm, 4.875” barrel
Kimber Target ll 1911 – 9mm, 5” barrel
Sig P210 Target Heavy Frame – 9mm, 6” barrel
DSA TP-9 – 9mm, 6″ barrel
Beretta Cx4 Storm – 9mm, 16″ barrel
Kel Tec Sub-2000 – 9mm, 16″ barrel
Special Weapons MP5 Clone – 9mm, 16″ barrel

Infinity – .357 Sig, 6″ barrel

Bond Texas Defender – .357 Mag, 3” barrel
Colt Detective Special – .38 Special, 2.125” barrel
Smith & Wesson 627-3 – .357 Mag, 5” wo brake / 5.625” with brake
Korth revolver – .357 Mag, 5.875” barrel
Winchester Model 94AE – .357 Mag, 16” barrel
Stoeger Buntline – .357 Mag, 18” barrel

Beretta 96 Elite ll Brigadier – .40 S&W, 4 1/2” barrel
Rocky Mountain Armoury Sphinx – .40 S&W, 4 1/2” barrel
Browning Hi-Power – .40 S&W, 4 5/8” barrel
Ruger PC4 Carbine – .40 S&W, 16″ barrel

Bond Arms “Texas Defender” Derringer – .44 Mag, 3″ barrel
Smith & Wesson 629-5 Mountain Packer (ported) – .44Mag, 3” barrel
Smith & Wesson 629-5 Performance Center – .44 Mag, 4 7/8” wo brake 5 5/8” with brake
Smith & Wesson Model 629 Classic – .44 Mag 6 1/2”
Smith & Wesson Model 629 – .44 Mag, 12” barrel
Henry Golden Boy – .44 Mag, 20” barrel

Smith & Wesson Model 325PD (Airlite) – .45 ACP Revolver, 2 1/2″ barrel
Bond Texas Defender – .45 ACP, 3” barrel
Para LDA PDA – .45 ACP, 3” barrel
Beretta Model 8045 Cougar – .45 ACP, 3.625” barrel
Ed Brown 1911 – .45 ACP, 6” barrel
Group IND UZI – .45 ACP, 16″ barrel
Kahr Thompson – .45 ACP, 16″ barrel
Vector Arms Kriss Super V – .45 ACP, 16″ barrel
La France M16 – .45 ACP, 16″ barrel

Bond Derringer – .45 Colt/.410, 3 1/2” barrel
Navy Arms Schofield – .45 Colt, 3 1/2” barrel
Cimarron (Uberti) Colt – .45 Colt, 5 1/2” barrel
Cimarron (Uberti) Colt – .45 Colt, 7 1/2” barrel
Beretta Stampede Buntline Carbine – .45 Colt, 18” barrel
1892 Winchester Lever Action Rifle (reproduction) – .45 Colt, 20″ octagonal barrel

Quite a list, eh?

Jim Downey

April 23, 2009 Posted by | .357 Magnum, .357 SIG, .38 Special, .40 S&W, .44 Magnum, .44 Special, .45 ACP, .45 Colt, 9mm Luger (9x19), Anecdotes, Data, Links | 1 Comment

.40 S&W

Here is a post pertaining to the testing and results obtained for the .40 S&W caliber.

November 26, 2008 Posted by | .40 S&W | 2 Comments



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