Ballistics by the inch

Been a busy month.

Hey everyone,

So, the BBTI relaunch just keeps plugging along. As mentioned previously, it’s hard to do a direct comparison in terms of hits and whatnot, but it is clear that on all fronts the numbers are up. Thanks, everyone!

I’d also like to thank those who have made donations to help defray our costs. Unfortunately, said donations do not help enough, and as a result sometime soon we’ll be adding in some Google Ads. We’re going to try and keep it minimal, and if donations continue to come in . . . well, we’ll see.

I’ve been keeping very busy with a number of different projects. I continue to do a lot of writing for, both feature articles and reviews. Check it out!

And I’m about to ‘launch’ the publication of my novel, Communion of Dreams. The Kindle version is now available, and the paperback will be available in a couple of days. When we ‘go live’ with the paperback edition, there will be three days when anyone will be able to download the Kindle version for free. That’s coming Friday, 1/27 through Sunday, 1/29 – watch for it!

Jim Downey


January 25, 2012 Posted by | Uncategorized | Leave a comment


I was checking the web stats, saw that BBTI is closing in on 2.5 million hits (probably hit that mid-afternoon tomorrow). A link from a site listed in the referrals had this comment about the project that I thought I would share:

“As I recollect, it was actually someones Master’s research project at the University of Iowa. Can you imagine doing graduate level work in external ballistics? Kinda cool.”

At first I just thought it was amusing, since we explain right on the homepage what prompted us to do the testing. But then thinking about it a little further, I realized that it was actually a nice compliment and somewhat insightful: what we did could be seen as being comparable to graduate-level study and research. I hadn’t thought of it that way before.

Jim Downey

(Cross posted to my personal blog.)

May 20, 2010 Posted by | Data, Discussion., General Procedures, Links, Uncategorized | 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

Some thoughts from the data graphs

JE  mentioned to me observing some oscillation in some of the graphs. I have spent a little time today working through all of the graphs and have the following thoughts:
– most of any oscillation appears in the “saturation” velocity tail. Since we have not put the “error/spread” bars on the data points I suggest that most of what one sees in the portion of the data is the natural variance in the ammunition.
– the smallest calibers show the biggest effect. With the lightest bullets a small variation in powder should produce a larger variance in the velocity.
– there is some anomaly in combining these two effects in a couple of the calibers. In particular I think it is the .44 spc and .45 colt.
– even with these, one can readily see that some of the ammo has maxed out and is actually slowing in the 18″ barrel.
jim k

December 13, 2008 Posted by | Uncategorized | | Leave a comment


As noted there to the right, this blog is intended to be a discussion forum primarily concerned with the ‘nuts & bolts’ of how we did our testing and the results we obtained, not a general gun discussion forum.  As such, you’ll find a number of posts already created pertaining to each of the different calibers, as well as some general topics – just go to the appropriate entry and pose a question or comment, then you can follow the discussion either by visiting the blog or subscribing to the RSS feed.  If a discussion thread gets too long, or takes a turn which warrants further attention on its own, we’ll create a new post and shift things over to it.

We reserve the right to moderate comments – to keep them on-topic, and to keep things ‘family friendly’ – but will take a fairly light hand insofar as possible.  Your cooperation on this is appreciated.

If you need to contact any of us directly, you can do so via this email address:

Jim Downey:

So, welcome – and jump in!

November 10, 2008 Posted by | Uncategorized | Comments Off on Welcome!