Ballistics by the Inch: Three Guys, Two Chronometers and 7000 Rounds of Ammo

Answers to many of the handgun caliber ballistics questions now exist at one website. The site covers muzzle velocity for 71 types of ammunition over 13 calibers.

Steve, getting ready to load, and the author (recording) at work with the baffle box.

“In a short barreled gun, the .38 Special and .357 Magnum are almost the same.”

 

“I really like the new Springfield EMP 9mm. What am I giving up in ammo performance going from five to three inches?”

“I really like my SASS .45 Colt single action, and since I use it every weekend I am good with it. I would like to use it as my home defense gun. Are the ballistics similar to the .44 Special or .45 ACP like I read in the magazines?”

“I’m looking into getting a .25 Auto carbine for varmint hunting.”

 

The last day of shooting, the rail flew off of the T/C shearing the barrel-mount threads so we could not remount the laser.

 

Okay, I made that last one up (I hope), but how many of such things have you heard, read or discussed? Did you search the web about these or similar questions only to discover that the answers are hard to find or involved a lot of hand waving?

Well, as of November 2008, answers to many of the handgun caliber ballistics questions now exist at one website, BallisticsByTheInch.com. The site covers muzzle velocity for 71 types of ammunition over 13 calibers: .25 Auto, .32 Auto, .32 HR Magnum, .380 Auto, 9mm Luger, .38 Special, .357 Magnum, .357 Sig, .40 S&W, .44 Special, .44 Magnum, .45 ACP, and .45 Colt; with barrel lengths in one-inch increments from 2-18 inches. And it’s free!

So how did this come about? The details are on the website including all of the relevant e-mails, photos, video, data and graphs. With everything public– warts and all–people will be able to see what we’ve done so they can improve it or add to it. This article is a much condensed overview. In early 2007, Jim Downey and I searched the web for information related to barrel length, ammunition, and ballistic performance.

Concealed carry: The ammunition we used. I it looks like Christmas but it felt like Halloween at times.

The ammunition we used. I it looks like Christmas but it felt like Halloween at times.

What information we found was scattered, sketchy and incomplete. Jim and I think it possible that such data might be maintained by ammunition and gun manufacturers but that in their opinion it would not be in the best interests of their company to provide it to the public. The gun press does some of this work but it is probably too expensive and time consuming to be able to do large studies and recoup the cost in copy sales. There is a growing body of muzzle velocity data provided by John Ervin at BrassFetcher.com alongside the ballistic gelatin tests which are the main thrust of that site.

Given the fact that some 40 states are now “shall issue” states for concealed carry licenses, we felt there really was a demand for a body of data collected in one easy to find location; at a minimum, data for the common self defense calibers. Since carbines exist for these calibers we decided to look at barrels from 2 to 18 inches in length. As the discussion progressed, I thought we might as well add in other calibers for which handguns are readily available.

We gave careful attention to selecting the platform for firing the ammunition. Semi-auto firearms would likely give different muzzle velocities than revolvers for the same ammunition. To avoid legal trouble caused by creating a short-barreled rifle, we decided on a Thompson Contender (T/C) handgun with a threaded quick-change mount to swap the eleven, threaded custom-made barrels (one barrel for the .38 Special/.357 Magnum and one for the .44 Special/.44 Magnum).

Concealed carry: The 18-inch barrels.

The 18-inch barrels.

The data produced by the T/C would be the maximum muzzle velocity for a given barrel length and ammunition, and the relative velocity changes should be correct for either a revolver or semi-auto pistol, even if the actual numbers would not translate directly.

Prior to starting the tests, the project was discussed with a few close friends and relatives. The most repeated comment was surprise that such a study had not been done already. “Yeah, sure you’ll do it,” was another frequent response. Some felt that while it was a worthwhile thing to do there must surely be more important things on which to spend the time and money.

At the moment that concrete planning began, Jim said we must set up a website to put the information in the public sphere once the study was completed. And he predicted it would be a big hit in the gun world. While waiting for the ammunition and barrels we hammered out the logistics of the study. Jim had access to land in central Missouri restricted from the general public, where the noise would not bother anyone and where we could leave some of the equipment overnight.

Concealed carry: A well shot log ready to be rotated or replaced.

A well shot log ready to be rotated or replaced.

A tent would house the chop saw for barrel cutting, the table where data was recorded and shots fired, food and drinks, and any other items needing protection from the elements. An electric generator was placed nearby in an old three-sided shed. The chronographs were set up approximately 12 feet outside the door of the tent. Behind them was an old cabin constructed of railroad ties. We used logs as the primary bullet stop and aim point. You tend to chew through them pretty quickly with 6,000+ rounds fired.

I had a strong concern about what effect temperature variation might have on the data over the course of several days. We discussed this with Steve Meyer, a friend with many years of experience in hand loading, chronographs, and shooting. Steve said that the effect shouldn’t be too much for the range of temperatures expected over a few spring days. Steve agreed to help with the actual tests, and he also provided one of the chronographs.

By late August, most of the ammunition and all of the barrels were in hand. But between family issues and, later, winter weather, the actual tests were delayed until several days in March and April, 2008. For most of the testing, the weather was between 40 and 50 F, wet and windy.

Concealed carry: Looking into the sound baffle box from the muzzle side, you can see the shredding of the cardboard by the muzzle blast. The blast was especially bad from two- to four-inch barrels.

Looking into the sound baffle box from the muzzle side, you can see the shredding of the cardboard by the muzzle blast. The blast was especially bad from two- to four-inch barrels.

We regularly rotated through the three jobs of firing, recording and cutting/ preparing barrels. The process started by recording the temperature. Three rounds were fired, the velocity recorded and a Bore Snake was passed once through the barrel. This was repeated for each type of ammo in that caliber.

When a caliber was completed for that barrel length another barrel was switched in. While the ammunition for the new barrel was being tested, the first barrel was being cut with the metal chop saw and the muzzle dressed with a rat tail file and honing stone, and then finished with three passes of the Bore Snake.

We fired a Colt Python using .38 Special ammunition at the beginning, end, and several times during the day as a control test. We started without any sights, but once the barrels got short the T/C became hard to aim so we attached a modified Weaver rail to the T/C and mounted a laser. The last day of shooting, the rail flew off of the T/C shearing the barrel-mount threads so we could not remount the laser.

Concealed carry: The baffle box needed a lot more material.

The baffle box needed a lot more material.

Steve did all of the final few hours of shooting as he was the most proficient at the no-sight aiming. The laser system worked well although we regularly had to rotate the batteries in the laser as the lead battery regularly developed a dent that prevented consistent contact. The testing started out as fun but, between the chill and tedium, quickly became almost grueling. Jim noted that if he never shot over a chronograph again it would be too soon.

The website was produced by Martha John, Steve Meyer and Jim Downey. Along with the frustration brought on by the amount of data reduction and entry, there were unexpected difficulties with the coding and making the site work. But it did reach completion and, with a few posts on several gun blog sites, was launched publicly on November 29, 2008. Within two weeks the site had 250,000 hits and was in the first two or three pages of relevant Google searches.

And what remains to be done? We missed a few types of ammunition: .327 Magnum (the ammo was very hard to get at the time), .41 Magnum and 10mm (both simply overlooked, but we will be testing all three of these in the spring of 2009). Obviously, ammunition changes so there will always be the need for retesting.

Concealed carry: The barrel here is slightly started onto the threads of the frame mount. While in the firing position the barrel is held by the black nut at about 1/8th turn from tight against the frame.

The barrel here is slightly started onto the threads of the frame mount. While in the firing position the barrel is held by the black nut at about 1/8th turn from tight against the frame.

Although we did test some of the calibers with real guns there is a need to do more complete studies with at least a few calibers in both revolvers and semi-auto pistols to get a feel for required adjustment to our T/C data for these platforms. Whether we or others do such tests, hopefully the results will be posted on the web.

All told, the project cost more than $15,000 and hundreds of man-hours of labor. But in the end it was a rewarding effort well worth the time and expense. We remind people to actually try their chosen pairing of gun and ammunition to make sure that it meets their ballistic criteria. And we hope that our work makes the narrowing of that gun and ammunition search a little easier.

 

 

 

[ Educated as a physicist with an ABD from the University of Iowa, Jim Kasper recently turned his interest in firearms toward some fundamental ballistics questions for the benefit of the firearms community. When not engaged in things firearms related, he enjoys woodfired ceramics and has been a full-time working artist since 1993 when he established his own studio, Prairie Dog Pottery. Most Saturday nights find him playing bass for The Lovedogs, a rock cover band in eastern Iowa. ]

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