Category Archives: Ballistics

There are three types of ballistics as it relates to firearms. Interior, exterior, and terminal. Joe wrote the PC app Modern Ballistics and Windows Phone app Field Ballistics.

I’m a “respected Idaho based shooter and author”

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Apparently I’m now “a respected Idaho based shooter and author.”

The background story is that I and several other bloggers were asked by the folks at AmmoForSale.com which of the three major calibers, 9mm, .40 S&W, and .45 ACP, was the best. I answered, via the blog post, and they just posted an article that incorporates some of my response.

I appreciate the kind words but I’m not sure I have all that much respect as a shooter compared to a lot of other people and I’m a “software author”, blogger, and occasional magazine article writer. I’m not really an “author” in the most common sense.

Still, I think they did a good job on their article even if they did give me more credit than I think I’m due.

More on “Barrel Harmonics”

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There is incontrovertible proof that those who talk about barrel harmonics do not know what they’re talking about, and that proof is in the very term they use to talk about it.

First; the term “harmonic” is a very specific term for an integral multiple of a fundamental vibration frequency. Since a barrel is (usually) a somewhat irregular object tethered at one end, I question whether most of them have a harmonic overtone series at all (like a guitar string or the air column inside a flute) or a primarily inharmonic one, like a bell or a cymbal. “You keep using that word…”

Second; the fundamental frequency of the “resonating” barrel is being ignored (by the language at least) yet the fundamental is often, or probably, more significant, i.e. it probably has a higher amplitude than the higher frequency vibrations. That’s usually very much the case with a vibrating body unless it’s being dampened at the fundamental. So why, particularly, are we discussing overtones (harmonic ones or inharmonic ones) and not the fundamental?

Third; don’t even talk to me about barrel harmonics, or barrel fundamental vibration, or inharmonic barrel overtones (A.K.A. “partials”) on an AK or a 30 Carbine, et al barrel. Just don’t.

I once had to do this with a class of music majors during a seminar I did at the U of Idaho. We were talking about advanced tweaks, the last one percent, of what goes into the design and structure of a musical instrument to make it a really fine one, and the students were responding as though I were talking about major issues. My fault. I should have been more clear at the outset.

So here it is; you don’t address the last one percent on your AK. It’s not a beanfield rifle. Please. There are several other factors that totally overwhelm the last one percent (like the previous 99 for example) and so if you address the last one percent as though it were “the issue” you’re ignoring the issues that matter.

What caliber for hunting?

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I seldom hunt but I do know a fair amount about ballistics. I only see one thing I disagree with on the info graphic I found here:

Choosing-The-Right-Caliber-Infographic

I’m pretty sure a .50 BMG would work fine for even the largest “Jurassic class” game.

Low-speed heavy bullet expansion

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I was pondering my earlier experience with bullet performance, and got to wondering about the other end of things, with low-velocity rifle bullets. When shooting at very long ranges, or when using a subsonic cartridge like a 300 Blackout / Whisper, what heavy .30 cal bullets expand reliably at around 1000 fps? Obviously something like a 200 grain Nosler Partition will hold together, but will it mushroom at all at low velocity? They only brag about expansion down to 1800 fps on their Ballistic Tip, which only goes to 180 gr. Their “long range” Accubond recommends greater than 1300 FPS. Now, with a BC of .730 in a 210 gr Spitzer it’s still going to hurt what it hits, but if you want to maximize energy transfer, punching a neat hole isn’t the way to do it.

Any thoughts, experience, recommendations, or rumors?

Downrange is a bad place to be

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Supposed to be real footage, from something like a thousand meters on full zoom. Not a fun spot to be filming from. Likely fake, but hey, it’s cool.

Field Ballistics bug fix

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I fixed a minor bug in Field Ballistics. The new version is 1.1.1.0. It is available on the Windows Phone store now.

The bug was that under certain situations you could delete the last target. Other places in the app required that at least one target exist at all times. After deleting the last target the app would immediately crash.

As a side note: I submitted the changed version Sunday evening. It made it through Microsoft certification in less than three days.

Terminal ballistics and truck skinning

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Got some pictures, some are kind of graphic – if you don’t like images of meat processing or bullet holes, don’t click. Continue reading →

When does a .30-06 do a thirty-thirty?

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When it has a spectacularly successful bullet failure. Continue reading →

Field Ballistics update

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I released a new version of Field Ballistics for Windows Phone earlier this week and it made it through Microsoft’s test gauntlet this morning.

Here are the changes in version 1.1:

A crash that occurred when measuring inclines has been fixed.

Auto conditions retrieves air pressure from the weather service and allows manual input of air pressure independent from altitude for user defined conditions.

Target range can now be set in the range edit box in addition to moving the target push pin on the map.

Cool shooting pictures

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Herra Kuulapaa has some really cool high-speed photos of guns being fired. I don’t want to take his art without permission, but they are pretty good. Pistols, revolvers, AKs, differences in powder, muzzle-breaks and not, pretty good selection.

Probable bug in Windows Phone 8

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I found what appears to be a minor bug in some Windows Phone 8 devices.

It showed up in my Field Ballistics program. I have code that looks like this:

// Can we focus only on the target?
if (this.cam.IsFocusAtPointSupported)
{
    this.cam.FocusAtPoint(0.5, 0.5);
}
else
{
    this.cam.Focus();
}

On someone’s phone this raised a “System.InvalidOperationException” on the call to “FocusAtPoint”.

What appears to have happened is that the phone reports IsFocusAtPointSupported as “true” but doesn’t actually support it. It’s not all that big of deal but it does mean I’ll be releasing an update a little sooner than I had planned.

Hat tip; theBlaze

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Happy Independence Day.

He probably complied too much, and should have stood his ground on the “Am I being detained” part. I don’t know what I will do when my time comes, but I have been through a similar incident before and it left a bad taste in my mouth. In that case I was in fact in violation, by having studded tires after the deadline for removing them. If I were totally innocent, who knows what would happen? I’ve seen the dog trick before too. It’s bullshit. I do know for sure that I will be asking the criminal posing as a cop to get out a pad and pencil and jot down “18 USC 241” and “18 USC 242” and informing him that he is putting himself at risk for prosecution.

A dashcam would be a good investment about now, to document the crimes committed by corrupt police, if for no other reason than posterity, so future generations can see how and when our republic fell into the shithole.

And you still use Android?

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Via a Tweet from Ry we have still more info on the security issues with Android (emphasis in the original):

The Bluebox Security research team – Bluebox Labs – recently discovered a vulnerability in Android’s security model that allows a hacker to modify APK code without breaking an application’s cryptographic signature, to turn any legitimate application into a malicious Trojan, completely unnoticed by the app store, the phone, or the end user. The implications are huge! This vulnerability, around at least since the release of Android 1.6 (codename: “Donut” ), could affect any Android phone released in the last 4 years1 – or nearly 900 million devices2– and depending on the type of application, a hacker can exploit the vulnerability for anything from data theft to creation of a mobile botnet.

While the risk to the individual and the enterprise is great (a malicious app can access individual data, or gain entry into an enterprise), this risk is compounded when you consider applications developed by the device manufacturers (e.g. HTC, Samsung, Motorola, LG) or third-parties that work in cooperation with the device manufacturer (e.g. Cisco with AnyConnect VPN) – that are granted special elevated privileges within Android – specifically System UID access.

Installation of a Trojan application from the device manufacturer can grant the application full access to Android system and all applications (and their data) currently installed. The application then not only has the ability to read arbitrary application data on the device (email, SMS messages, documents, etc.), retrieve all stored account & service passwords, it can essentially take over the normal functioning of the phone and control any function thereof (make arbitrary phone calls, send arbitrary SMS messages, turn on the camera, and record calls). Finally, and most unsettling, is the potential for a hacker to take advantage of the always-on, always-connected, and always-moving (therefore hard-to-detect) nature of these “zombie” mobile devices to create a botnet.

I’ve known there were lots of security issues with Android but this is much bigger than I imagined. If you were concerned about various three letter agencies sucking up data about you (or even your snail mail) then you should be even more concerned that just about anyone that is technologically competent can take complete control of your Android phone.

A little over two years ago I purchased a Android phone with thought of developing apps for it. I never got around to it and after releasing Field Ballistics for Windows Phone I gave it further consideration. I decided not do pursue Android as an alternate platform. I’m glad I made that decision. Would you want everyone and their brother looking at the map on your phone showing your location and the location of your next target? At Boomershoot that would be an invitation to have “your” target poached.

What’s the best caliber?

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It happened again. Someone asked me what I thought the best caliber is. Granted they didn’t ask it quite that ambiguous. But it did raise the “insufficient information hackles” when I got the email.

The actual question was:

Tell me which caliber you think is best and why:  9mm, 40 S&W, or 45 ACP.

Had the question been, “Which caliber has the best stopping power?” I would have replied, “It’s tough to beat something chambered in 200 mm XM422 with the 40 kiloton yield option”.

The question isn’t quite that unbounded but still it’s insufficiently bounded to give an answer that is credible for even a fraction of the possible values of the unconstrained variables. One must really have more information about the use cases of the firearm before you can give an answer that someone couldn’t drive a Euclid truck through.

When someone asks a question like this what you really need to do is get the person asking the question to answer it for themselves. For all intents and purposes they already know the answer they just don’t know the proper questions to ask themselves. You can help them with this.

The top level question is, “What are you going to use this gun for? Recreation, self-defense, competition, all of the above?” One could drill down to a depth of three or more in the specifics for any of the answers given but here are few of the possibilities:

  • What is your ammo budget?
  • Self-defense against two legged varmints or four?
  • What is the body mass of the varmint you need to defend against?
  • One attacker or a mob?
  • Which sport?

Everything is a tradeoff. The smaller calibers tend toward higher capacities, higher velocities, lower costs, and, obviously, smaller holes. With the larger calibers the opposite is true. Once you figure out your application then the caliber question should pretty much answer itself.

If you are interested in self-defense “stopping power” then I answered that question nearly 15 years ago and I don’t see any reason to update the conclusion where I agree with Greg Hamilton who says:

The entire discussion of “stopping power” is both stupid and irrelevant.   Statistics cannot be applied to individuals. People that need to be shot need to be shot soon and often. They need to be shot until they run out of fluid, brains, or balls.

If during the time you were reading the latest “stopping power” article you were instead practicing to save your life you would be far, far ahead.

Greg Hamilton
May 08, 1998

Of potential interest is what caliber gun(s) do I own and use and why.

I have guns in all three of the calibers in question. I almost never use the 9mm or the .45. The reason has nothing to do with the caliber themselves. It is because a .40 with 17 or 18 round magazines is the best choice for Limited class USPSA matches which I compete in. I can compete in USPSA and Steel Challenge with it and I can carry it for self-defense. I figure the odds of me using it in self-defense are pretty low but the probability of me using it in competition are near 1.0. And even supposing that some other caliber/gun would be better for self-defense the fact that I am going to be practicing with the competition gun is probably going to make up for the (questionable) fact that I wasn’t shooting the optimal caliber.

Field Ballistics is “Top Paid”

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I found this surprising*. Very pleasing, but surprising:

WindowsPhoneTopPaidSports

Field Ballistics on Windows Phone is in the list of “Top paid” sports apps after being out for only a week.

See my announcement here. Purchase it (or get a free trial version) here.

*Assuming no inflation, sales remain constant, and I saved and invested every penny then in another 1000 years I might be able to retire on the proceeds.

Field Ballistics is available on Windows Phone

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I just received notification that Field Ballistics for Windows Phone has passed the Microsoft certification tests and is now available in the store. It may take a day or two before you can search for it in the store but you can install it now using this link.

Some of the cool features are illustrated with the following screen shots:

ScreenShotMap

The shooter and targets are placed on a map. The program automatically computes the range to the targets. It also automatically computes the direction of the wind relative to the bullet flight path. This means that if the wind is from the west and you are shooting at a target to the south you will get the correction the full value of wind drift. But if you then choose a target directly east (or west) of you the wind correction will be zero. Of course all the trigonometry is done to correct for shooting in all directions.

At the bottom of the screen are two columns. The left column is the ballistics solution to make the shot at the selected target. In the right column is data about the target and the bullet when it arrives at that target. Of particular note is that in the case above the bullet velocity is in red (the theme color of the phone). This means the bullet velocity is below the minimum you have specified in the settings. This is particularly important for Boomershooters because the targets won’t detonate if the bullets are going too slow.

Tapping the ‘S’ or ‘T’ icons at the bottom of the screen moves the center of the map to the shooter or the selected target. The down arrow icon moves the selected target (or the shooter if it was selected) to the location of the phone using the phone GPS. This means that you can set up multiple targets on the map, then the shooter can “run and gun” and get ballistic solutions quickly. By using the GPS to get the current location of the shooter the distances and wind corrections are automatically update for each position the shooter wishes to shoot from.

ScreenShotTargets

You can add as many targets as you wish* and give them user friendly names. If you tap the “Measure” button you can use the phone camera and accelerometer to determine the incline to the target from your current location.

ScreenShotIncline

This is the incline measurement screen using the camera. You put the crosshairs on the target and tap “Done” to capture the incline of the phone for this target. You can also zoom in or out and refocus the camera.

[Please note this is only to illustrate the incline measurement feature, not to advocate shooting in cities.]

ScreenShotConditions

The automatic weather conditions are obtained from the current location of the shooter. This doesn’t mean the physical location of the phone. You can position the shooter in another state and the nearest weather station to the designated shooter location will be used. When you define your own conditions you can even use the phone GPS to capture your altitude.

ScreenShotCartridges

Black Hills and Federal match ammo are predefined. Add as many of your own cartridges* as you desire.

ScreenShotRifles

Some predefined rifles are included but you can add as many of your own rifles* as desired.

ScreenShotHelp

There are pages and pages of easily accessible help on the phone.

*The trial version only allows one target and one each of user defined conditions, cartridges, and rifles.

Field Ballistics failed certification testing

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This afternoon I received an email from Microsoft telling me my new phone app failed the certification testing.

There were two errors. In the first case I didn’t have a clue I was violating the policy. In the second case I was careless. Both are easily fixed.

Test failure 1:

Test: Content that is offensive in any country/region to which your app is targeted is not allowed. Content may be considered offensive in certain countries/regions because of local laws or cultural norms. Examples of potentially offensive content in certain countries/regions include, but are not limited to, the following:

Group 1: China
Prohibited Sexual Content
Disputed territory or region references
Providing or enabling access to content or services that are illegal under applicable local law

Comments: Result: Fail
Your application uses the Bing Maps Silverlight Control for Windows Phone. Bing Maps is not supported for Group 1 countries at this time. You may resubmit your application and deselect the Group 1 countries.

Test failure 2:

Test: Screenshots must only contain app graphics, and must not include any emulator chrome, frame rate counters or debug information.

Comments: The application screenshots contain frame rate counters and debug information.

Three out of the eight screenshots had the frame rate counters and debug information in them. I knew better and just wasn’t paying close enough attention in my rush to get the app submitted.

It will take 30 minutes or so to fix it and resubmit. I’ll get to that sometime tonight after visiting my son and his family.

Quote of the day—J

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Now I want a Windows phone. You’ve done what the marketing department at Microsoft could not.

J
June 12, 2013
[This was in response to my post about “shipping” my exterior ballistics app for Windows Phone.

That’s pretty pleasing because one of the things that weighs heavy on my mind is that, as Barb L., reminded me the night before I submitted the app is that, “This is for people that are really into long range shooting and own a Windows Phone. That’s a pretty small market.”

Totally off topic. I don’t know who ‘J’ is in this context but my first thought was the author of this book. I’m pretty sure the author of that book wouldn’t use this gravatar so I can rule her out.

I remember Larry H. giving me copy of that book when he was finished with it. I was sophomore in high school at the time it opened my eyes about some things. Then my dad found it tucked behind some insulation in the attic and took it away.—Joe]

Field Ballistics for Windows Phone

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I just submitted my exterior ballistics app, Field Ballistics, to the Microsoft store for Windows Phone. It will be a few days until it is published. In a day or so I’ll give more details but here is some of what I submitted:

Field Ballistics is a revolutionary exterior ballistics application. Previous ballistics app are little more than glorified pieces of paper with ballistic tables. Field Ballistics uses the phones high tech capabilities to give ballistic solutions for multiple targets.

Place push pins on a map for each target automatically computing the distance from shooter to target, use the camera and accelerometer to measure the incline, use the Internet to automatically get up to date environmental conditions from the closest weather station. Select a target on the map and see the exact scope settings needed and information such as the time of flight and bullet velocity at impact.

When the shooter moves to a new location the ballistic solution for each target is automatically updated. Range and wind direction are automatically corrected using the new shooter location and information from the nearest weather station. You just enter in the new scope settings and take the shot.

Select from any of Federal or BlackHills match ammo or add your own. Input chronograph velocities and Field Ballistics corrects for the distance from the chronograph to the muzzle.

Field Ballistics is more than a glorified piece of paper. It uses the full power of your phone to give you ballistic solutions to multi-target problems.

ScreenShotMap ScreenShotConditions

I started seriously working on this about a year and a half ago. It feels really good to get it out the door.

Update:

In response to this comment from Ray what follows is the exact text of the privacy policy stated in the app:

Requests for map and location information from Bing and other Microsoft services are made by this application and may include the current location of your device. This application uses the Microsoft location service for some actions.

These actions will cause the location of your device to be stored on the device. This information, and all other data for this app, can be deleted by using the ‘reset’ menu item. The use of the location services can be disabled by using the ‘disable use of location services’ menu item.

If ‘Auto’ shooting conditions are used then requests for current weather conditions at the shooters location are made from wunderground.com.

Other than as disclosed above, no information of any type is ever sent by this application to any other device, user, application, or web site for any purpose.

First shots

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For some reason I put together another AR. I’ve had a pretty nice Colt’s Match HBAR for years, but I thought a light carbine would be good to have around for kids, new shooters and such. My daughter might want it at some stage.

This new one is cobbled together from nearly as disparate a set of parts as is possible. I think every parts group is made by a different company. The aluminum, railed gas block, for example, was knocked out on an old Bridgeport mill by Some Dude in Moscow, Idaho– I had to mount it on the lathe and trim it down a bit to make it clear the floating handguard, which is a used piece off of Some Other Dude’s AR. It’s all assembled as a mock-up right now. Mostly new parts, some of the metal being in the white. I wanted to proof test it before taking it all apart again, bead blasting it and giving it a finish of some kind.

Since none of the working parts had ever fired a cartrige before, I cranked off four rounds with the carbine held at arm’s length, one-handed, into a hillside (the thought had come to mind that the thing could blow up, and if it was going to do that I wanted it to happen far away from my face). Perfect function. All ejected cases ended up in a nice tight group off to my right, too.

After putting a few shots on paper at 25 yards, I took it out to 100 to get a good zero on the TX30 reflex sight. Here’s the 100 yard target. I fire two-shot groups for initial sight-in. One-shot “groups” would probably be OK for starters, but I like to get some sense of how I and the rifle are working together. The first 100 yard group is the one holer at the top of the paper, on the “1L” line. I’d thought that the TX30 had 1/3 MOA clicks like an ACOG telescope, so I over-compensated, putting the second group near the bottom of the paper. The TX30 has 1/2 MOA clicks, and the fact that the target was stapled to a log and was slanting back quite a bit accounts for the larger apparent error. Splitting the difference with a few “up” clicks, and a couple clicks left, the third group was pretty well dead on;
100 Yard Sight-in

I have a padded steel rifle rest and some shooting bags, but I’m using them less and less. If you can’t use your vehicle, a stump, a tree branch, a rock, the ground or your knee, what kind of shooting are you practicing? In this case I was mono-podding, holding the 30 round magazine in my hand and resting the hand on the hood of the pickup. It works well enough. The truck bumper is OK too, or the tail gate, or a front tire steered over to one side. The tip of a longish snowshoe can make a decent place to rest your knee in a kneeling position… There are lots of options, so you can haul around less stuff.

Three consecutive two-shot groups of around 1 MOA and less. I be happy for now. Don’t ask me to repeat it. It was getting dark so I called it a day and let the dog out to romp around for a bit and get wet and smelly before the ride home. Ultimately I think I’ll want a solid 200 yard zero for this reflex-sighted carbine.

Dealing with “issues” while shooting is a good thing. In this case it was failing light, mosquitoes, my dog which hates gunfire (he ended up inside the pickup, and his moving around made the pickup, which I was using as a shooting rest, move just a little bit while aiming) and the fact that I’d ended up out there with no spotting optic so I had to trot the 100 yards back and forth to determine shot placement. That and there were people driving up and down the road, which was close enough I didn’t want to fire while people were so close and make them nervous. So I’m looking around, listening, swatting bugs, dealing with the dog, hurrying, and huffing and puffing a little. It’s an exercise in being very still while immersed in little stresses and distractions. That’s part of why I like rifle shooting so much. It’s wonderful. Sometimes it works out great and other times you chalk it up to learning. This time was like a dream, but I’ll have to figure out what happened to my 20×60 binocs.

This new light carbine is pounds lighter than my scoped HBAR rifle. I think it’s going to be one of my favorite shooters. I’d never “built” an AR before, and even though I’d had my Colt, and a Rock River, apart many times it was surprising to me how easy it was to cobble one together from parts. A fairly small child could do it, with a little bit of instruction.