Ballistics by the inch

From Gatling Guns to Laser Pistols.

Again, it’s been a while. Partial explanation towards the end of this post.

So, the BBTI team finally got together to do something we’ve been wanting to do for several years now: shoot a Gatling Gun. Yep, a real, honest-to-gawd Gatling Gun. Well, not an original, but a faithful reproduction of the original 1862 patent version, in .45 Colt. This one:

Keith checking the gavity-fed magazine.

It’s such an iconic weapon, having been used around the world for about 50 years (from the American Civil War until World War One). And almost anyone who has seen Westerns has probably seen one depicted on the screen. So when the opportunity presented itself to get a fine reproduction one at a reasonable cost, we jumped on it. And last weekend we were finally able to coordinate our schedules to get out to shoot the thing.

But first we had to assemble it, because it breaks down into several components for ease of transport and use. Overall, the whole thing weighs more than 300 pounds. The main element is the barrel & mechanism assembly:

Barrels & mechanism.

We’ve got a nice tripod to mount and shoot the gun. Here we are assembling that:

Tripod base.

On top of the tripod is a pivoting mount, so you can rotate the gun from side to side. Into that goes a yoke mount, to which the gun is secured. Elevation is controlled by an adjustable wheel screw at the back.

The way the gun works (the Wikipedia entry is pretty good, as well) is that you put the cartridges into machined sections of heavy steel tube called a ‘chamber’ (essentially, a section of barrel), and those are placed in a magazine. The magazine goes into the top of the gun, upside down. Each chamber drops into position behind a barrel, then is pressed forward and locked in place as it rotates to the next position. The barrel then rotates again into the firing position, a firing pin ignites the cartridge, and the bullet fires. As the barrel rotates again, the chamber is released, and falls free out the bottom of the gun. This process is repeated for each barrel in turn as long as you turn the crank and there are chambers in the magazine.

Here you can see a test run with empty chambers to make sure everything feeds and falls properly:



Next, we wanted to make sure that the firing pins were working properly:

After that, it was time to load ammo and give it a try.

I’d loaded 1000 rounds of .45 Colt, using 200gr lead bullets and 6.1gr of Titegroup powder. This is a mild handgun load, but we weren’t looking for a lot of power, just a lot of fun. Still, out of the 30″ barrels we were probably getting about 1,000fps and roughly 450ft-lbs of muzzle energy — a respectable amount of power.

Here’s Keith of the BBTI team giving the Gatling Gun its first live-fire trial;

Yay! It worked!

Soon, I got my turn:

Dude, that’s way cool.

OK, several things we discovered in shooting the Gatling Gun …

One, you quickly realize that once you start turning the crank, you find there’s an optimal speed where it feels easy and consistent. I got there at the end of the video above.

Two, you can go through the 44 rounds that our magazines hold in about 20 seconds when you know what you’re doing.

Three, it helps to have someone actually hold the magazine in position, rather than relying on the small set-screw to hold it.

Four, the gun is surprisingly accurate and consistent. Once we got the hang of it, at 20 yards (the effective distance we had to shoot it), we were all getting paper-plate sized groups. Like this:

The first target. All the rest were this good or better.

Seriously, I was very surprised by this. I expected something more like “minute of cow”. I look forward to shooting it sometime at longer ranges to see just how good you can get with such a gun.

After we all had fun shooting the modern ammo, it was time to try the gun with black powder cartridges. Specifically, 30gr of Goex FFg and the same 200gr lead bullet. I shoot a fair amount of black powder, and know that it can be messy … but man, it was an incredible mess in the Gatling Gun. But it sure was spectacular. Check out the long tongues of flame from this sucker:

And just think about what a battlefield with a bunch of those cranking out rounds would have been like. Blimey.

Now that we’ve finally had a chance to get together for an inaugural shoot of the Gatling, it’s something that each of us is going to take for a while, and share with friends. Look for more coverage of it in the future.

So, what was that about Laser Pistols, and why have I been so absent/quiet here for so long?

Well, about a year and a half ago I got a Glowforge laser cutter, which I mentioned in passing in my post last November. I kinda fell into a deep hole playing with it since then. But it’s all good, because one of the things I have been doing with it is making a whole bunch of handgun display models/art, like this:

Springfield XDM

That’s one of the 42 contemporary designs I’ve done.  I’ve also done a bunch of historical firearms, such as the 1851 Colt Navy Revolver:

Colt Navy Revolver

And even favorites from various Science Fiction franchises …

Farscape Pulse Pistol

The whole thing can be found here:  Art of the Gun and I invite you to stop in, check it out, see the many different designs I’ve come up with so far.  I’ve just launched the site, but already it is starting to get some positive feedback — so maybe you’ll find something you like there as well.

One last thing: we’re not done with the BBTI project. Something else we did this past weekend was to start talking about future projects related to our ongoing research. It’s too early to say too much, but rest assured that we have more work yet to do, more data yet to gather and share.

Thanks for coming by, and for your ongoing support.

Jim Downey



August 21, 2019 Posted by | .45 Colt | , , , , , , , , , , , , , , , , , , , | Leave a comment

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).

November 28, 2013 Posted by | 9mm Luger (9x19), Anecdotes, Data, Discussion., Links | , , , , , , , , , , , , , , , , , | 1 Comment

Take a chance on a holster.

I haven’t mentioned it here yet, but last weekend I launched a Kickstarter project to support my next novel:

St. Cybi’s Well – a prequel to Communion of Dreams by Jim Downey

Prequel to the popular novel Communion of Dreams. Get an early release download or a hand-bound copy in your choice of cover material.

So, *why* am I mentioning it here now?

Well, yesterday I got an unexpected box in the mail. Sometime a few weeks back I contributed a few bucks to a firearms-related website, and was entered into a drawing for various goodies. I never win these things, but participate just to be supportive of groups I like. Anyway, as you might have guessed, I actually won something for a change. This is what the box contained:

Here’s the holster with my Springfield EMP in it:

This is a perfectly nice holster, made by  It’s marked as being for an “L-frame” S & W revolver with a 2.5″ barrel, but as you can see it isn’t molded specifically for that, and seems suitable for IWB use with a range of medium-to-small guns. I also tried my Steyr S9 and M357 guns, which fit perfectly, and smaller guns such as a Bond Arms derringer would also work, but ride deeper in it. A full-size 1911 and my Colt Python both fit fine, but the barrel protrudes out the end.

Now, the thing is, while this is a mighty fine holster, it’s made to be either used IWB or OWB left-handed. Note the position of the clip in the second image above. To me, it’s useless (or almost so). As I was thinking of how to find a new home for it, I also got to thinking about several other holsters of varying quality I have which I have wound up with but which I never use and I had another idea: use them for a promotion for the Kickstarter.

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 a 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 each week or so while the Kickstarter is going I’ll select a name and send that person whichever holster is up for grabs. Each winner’s name will go back into the hat for the next drawing, so you have multiple chances to win (meaning that the sooner you enter, the better for you).

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

So, what are you waiting for? Go – get entered!

Jim Downey

September 21, 2012 Posted by | .357 Magnum, .357 SIG, .45 ACP, 9mm Luger (9x19), Discussion., Links | , , , , , , , , , , , , , , , , , , , , | 2 Comments

June? Already?

Yeah, seems to be. So here’s the numbers & info for the last month, plus a little look ahead:

We had 19,937 visitors to the BBTI homepage in May. We’ve added a number of additional review links to the list of Real World Guns. Followers for both Twitter and Facebook have also seen a nice uptick this last month.

Back in March I reported on how Google Adsense had screwed us over. Well, after looking at a number of options and being realistic about what kind of revenue advertising could generate, we’ve pretty much decided to just give up on advertising — with one small exception for now: you’ll note that some of the BBTI pages have a small ad promotion my novel. It is proving to be very popular, and the reviews for it have been quite positive — check it out. Of course, we’re still happy to accept donations to help offset expenses associated with BBTI — and thanks to those who have donated!

Happy & safe shooting, everyone!

Jim Downey

June 1, 2012 Posted by | Anecdotes, Discussion., Links | , , , , , , , , , , , , | Leave a comment

…bring May flowers.

Well – I see that I didn’t post stats last month for March. Sorry about that – a combination of being busy promoting my novel as well as getting together with some of the other BBTI guys to do some fun shooting (and to try out a .460 Rowland conversion kit for a Glock 21!).

So, first things first: March had a total of 21,499 visitors, and April had 19,918 visitors. Just a bit of a slow period there.

Next, remember that we’re now linking from the BBTI page on Real World Guns to reviews of said guns I’ve written for There are usually a couple new each week, so check back often!

And here is the first of some additional reviews from my shooting expedition the beginning of April: Wise Lite Arms Sterling 9mm. Coming weeks should see more than a dozen other reviews of handguns and PCCs (pistol caliber carbines).

A quick note that things with my novel have been going great, and so far some 14,000 people have downloaded the Kindle edition. If you enjoy my reviews and articles, then you may want to check out the book – it’s been getting a lot of really good discussion and reviews.

May 1, 2012 Posted by | .460 Rowland, 9mm Luger (9x19), Anecdotes, Links | , , , , , , , , , , , | Leave a comment