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.

Playing With Fire

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That’s fire and brimstone.  This is pure gun geekery, and even for gun geeks its nerdy because it’s about percussion guns of the 1800s.  You’ve been warned.

Saturday, Nephew and I tried some heavy loads for the repro 1858 Remington revolver.  I’d been using a 28 grain powder charge and a round ball with decent results, but wanted to try something with more pep.  Civil War era military loads ranged from very light, to as much powder and lead as could be stuffed in the cylinder.  To start, we tried round ball (~140 grains) over a charge of 39 grains of 3F Goex with a greased felt wad in between.  That load filled the chambers completely and delivered an average of 925 fps at 10 feet with an extreme spread of 46.  Not too bad.  The 29 grain charge was yielding a velocity of about 850 fps.

It’s like pulling teeth to find acceptable “conical” bullets (“bullet shaped” as opposed to a round ball) for these “.44” percussion revolvers unless you cast your own, which I don’t.  I did find some Buffalo Bullets 180 grain jobs that fit the chambers nicely, and ordered 100 of them to try.  Since the bullet takes up more room in the chamber, the most powder I could get in and still seat the bullet below the cylinder face was 30 grains.  But, wow.  Average velocity was 1047 fps.  That’s a tad better than a .40 S&W, and matches the V of a .45 Auto load in the Speer manual for their 185 gr GDHP.  Extreme spread was 67, with a standard deviation of 21.

That was with two different people doing the loading.  I’m going to guess that with the same person loading all the rounds, the charge weight and ramming pressure would be a little more consistent, and so too the velocity.  Groups with this load opened up slightly from last week’s all-ball venture, but not enough to be sure.  This time was in direct sunlight, which makes aiming a little more difficult.

The extra pressure it takes to move the heavier bullet, which also has more friction surface against the bore, I will assume ramps up the powder’s burn rate.  More velocity with less powder and a heavier bullet.  Neat.  We’ve found a performance, or efficiency, zone.  More pressure equals more heat, equals a faster, more complete burn inside the bore, equals yet more pressure.

This is how guns (and sometimes chemical factories, engines, etc.) blow up– things look great as you increase the pressure and temp a little.  The reaction speeds up, a little bit more, things are doing fine, a little bit more and, Boom!.  A threshold is reached and a runaway reaction takes place.  You shear some bolt lugs, or burst a cylinder, etc. and maybe you go home with slightly fewer or slightly misshapen body parts.  That can be embarrassing.

I wasn’t worried about this load in a modern repro made with modern steel.  When these revolvers were designed and built originally, metallurgy wasn’t anything like it is today, and even back then they were known to stuff the chambers full on a regular basis.  Further, it makes no sense to build a cylinder that will take more powder than it can handle with the commonly used “44-100” bullets of up to 250 grains.  That would take more material and make the gun bigger and heavier, for no other reason than to encourage over-pressure loads.  I’m also running on some faith that they wouldn’t have done that (though the much longer 1847 .44 Colt “Walker” cylinder was known to occasionally let go).  Remember that back then there was only black powder, not the wide spectrum of nitro powders we have now.  All they had to control the powder’s burn rate were different granulations of the same mixture (though brand and lot inconsistency would likely have thrown in some degree of uncertainty).  With smokeless propellants you can get into a LOT MORE TROUBLE making your own loads.

Here’s Nephew torching off one of the heavy loads.  The bullet has been on its way for about a millisecond, as the gun is still in firing position and the hot gas (I mean hot– this is in direct sunlight) has traveled a foot or so out from the muzzle;

Below is the same shot in full recoil a fraction of a second later.  Forget about quick follow-up shots.  You can’t see the target until the smoke clears. By then you’re re-cocked and ready to go.  A side wind would be a big help in this case;

Today’s rapid fire guns wouldn’t be worth as much if they had to run on black powder.  For one thing you wouldn’t be able to see squat.  It is “interesting” to take a shot, and find that your target has simply disappeared after the smoke has cleared.  There’s that moment of uncertainty.

I like the slow, frame-by-frame animations as below.  You can see the mechanics of the recoil (though a high speed camera would be nice).  You can watch the force wave travel from his wrist, into the arm, the shoulder, and whole torso.  Nephew’s grip is fairly relaxed, which isn’t a problem with a medium weight 44 revolver.  Some people hate animated gifs on a web page.  I’m one of them, but this is for science;

You shouldn’t haul off and max out your charcoal burner just because I did.  I’m not saying it’s the thing to do.  What I can say is; I still, for the moment, have all my body parts (and gun parts) and all are operating satisfactorily, thank you.  I have a load that’s within the range of those used in the 1860s for the Remington New Model Army revolver and 1860 Colt Army, and it matches some of the .45 ACP loads for a ~180 grain bullet.

Now here’s a puzzler.  I’ve had barrel leading in modern revolvers and autos firing bare lead, hard-cast or swaged bullets.  Using pure, soft lead bullets in the ’58 Remington and ’51 Colts, no leading has been observed, even with these loads that achieve modern handgun KE levels.  I don’t know why.  Is it the grease?  But we’re told in no uncertain terms never to lubricate a modern gun bore, while black powder guns are greased all to hell.  Is it the propellant temp?  But the KE is the same.

Food Processing. Protein; Step One

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It Was a Bright and Calm Morning…

My son and I both decided to hunt Late Muzzleloader season this year for a simple reason– there are far more does and “antlerless” bucks in our little hunting spot than antlered bucks, and this season allows harvesting of “three point minimum or antlerless” white tail deer.  Hunting muzzleloader season gives us a high probability of harvesting deer within walking distance of home.

We have one functioning muzzleloader rifle (step one food processor) so Son was given the first watch at the tree stand.  The second time out he took a decent young buck (small nubs for antlers) on Thanksgiving Day.  He spotted it while climbing down the tree, and shot it with the rifle still tied to the cord we use for raising and lowering things from the stand.  After that I started going out to the stand, but saw nothing in several days.  That’s unusual, but a deer had just been taken right there by Son.  Maybe they’re a bit spooked.  Don’t know, but on the morning of the last day of this one-week season, I got tired of sitting in the stand (besides, it was cold) and decided to take a walk.

It was a beautiful morning, just after sunrise, so if I never got a deer, it would still be worth the nice walk along the top of the picturesque basalt cliffs above the Palouse River.  There are always a lot of deer tracks up there, as it’s their only option for traveling between their feeding grounds (farmer’s fields) and their primary source of water.  My trouble that morning was that if there were any deer, they’d be immediately alerted to my presence.  Every 50 yards or so as I was walking along the ridge, a pheasant or two, or about 50 quail, would explode up from near my feet.  I might as well have been blowing an air horn every 50 yards and carrying a boom box playing rap music.

There’s a place along that ridge that’s down in a depression, and has some flat land with 360 degree concealment.  I knew in advance that if I was going to see a deer along the ridge away from our tree stand, it would likely be there.  As I topped the rise, getting ready to look down into the depression, I went slowly, making no sudden movements.

Sure enough, there were two deer, and one of them was a very nice eight-point buck!  About 200 yards away, he’s looking in my direction.  The sun being directly behind me, I was casting a 100 yard-long shadow right in his direction.  Pure stealth isn’t much of an option, but I was moving very slowly so as not to alert them too much.  Whack-a-Whack-a-Thump-a-Thump-a-Thump!!!  A pheasant exploded up at that moment about six feet away from me, so the buck got real nervous and trotted away.  It’s been years since I saw a nice buck up there, and, aware of my presence, this one and the doe are now on the move away from me.  Oh well. (but they didn’t bolt, as often happens)

I can either back-track less than a mile, cross the bridge for home and get ready to go to work, or I can go on, crossing another bridge about a mile ahead.  That’s an easy choice– I keep going forward in the direction of those two deer.  Wham, Slam, Whack!– quail and pheasants continue to announce my presence.  This is getting hopeless.  But it’s sure a nice day for a walk.

The deer never panicked, I guess, so what ended up happening was that I was dogging them.  They’d put some distance between us,  I’d close in, and they’d make some more distance.  Repeat.  Eventually they made a wrong move.  Some more quail (announcing my presence, but not telling exactly where) must have startled them out of the thick brush and into the open field.

I did not expect that.  They were in range, barely, but moving away fast.  Too far away to attempt a shot on a moving target.  No shot.  What do you do in this situation?  I whistled.  Deer whistle (I guess it’s more of a fast hiss than a whistle) at each other as an alert message.  Anyhow, it worked.  They stopped, turned 90 degrees broadside and looked back at me.  From that moment, circumstances dictate action.  No time for kneeling, and that might scare them off, so standing it is.  We’re all in the open.  Lock to full cock.  Backstop?  Check (there’s a hill a couple hundred yards behind them).  Front sight.  This is a longish shot for this weapon with open sights from standing– about 80 to 90 yards (I’ve never fired this rifle at anything more than 100 yards distant – maybe that has to change, but I’m confident at 100 and this is a bit less).  Some vacillating takes place for about a second.  One shot, one chance.  Too far?  Wobble area looks good.  Too far?  They’re still standing there, stone still.  This is a hair trigger.  Sight’s right on the sweet spot, what’re you waiting for?  Too far?  Nope.  Bang!

The two deer took off running.  The usual question comes to mind; did I miss?  They’re running fast and far.  200 yards and they’re out of sight over a rise in the undulating fields.  Oh well.  It’s a nice day for a walk.  Should I reload?  Maybe.  Have to cover 200 yards to look over that rise and try to spot them.  Better do that.  There they are; waaaay out there and still running.  I must have missed, though the let-off felt fine.  Damn.  But wait.  The doe’s way ahead of the buck.  Buck slows down and stops.  Then he looks like he got tired and decided to have a little lie down.  That’s odd.  They only ran about 1,000 yards.  No, it can only mean I got him.

He’s lying down with his head up.  Better reload.  I carry two reloads– plastic cartridges that contain a measure of black powder, a ball with lubricated patch, and a percussion cap.  They’re nice because you can use the cartridge structure as a short ball starter.  It’s easy– you just place the ball end over the muzzle and smack the other end, like so… Oops!  Forgot to pour the powder in first.  I have just dry-balled the gun and there’s an injured buck (I don’t know how injured) down there.  He could get up and run away.  I could lose an injured deer.  This sucks.  My chosen method of removing a dry ball is to seat the ball all the way down, remove the nipple and trickle a few grains of powder through the flash channel into the breech chamber, cap, then fire.  Works like a charm.  I have no nipple wrench.  Who needs to remove a nipple in the field on a half-day hunt? (it’s coming with me from now on)  The nipple’s seated tight– can’t break it free with the Leatherman tool.  Damn, damn, damn.  I eventually was able to pry the ball out at the muzzle, using the awl accessory (if I’d rammed it down I’d be hosed).  Cool.  Didn’t scratch the muzzle ’cause the patch protected it.  That ball is toast, but I have one more reload.

Meanwhile, the buck is lying there, looking around…head up, head down, head up, head down again.  Did he die?  Head comes back up.  Crap.  I had to get close enough for a 100% sure CNS (Central Nervous System) shot.  Walk slowly.  40 yards, take aim.  No.  Why not get closer?  30 Yards, kneel, full cock, put a shot through the neck at the base of the skull.  He drops like a stone.

This is not a good place from which to pack out a large deer.  Good net coverage.  Kamiak Butte, with the cell towers, is only 6 miles to the southwest.  I call Son on the phone.  No answer.  I wait and call again.  No answer.  I call my wife– she should be getting ready to drive to school.  Maybe she can meet me on the Colfax highway a few hundred yards over a hill and bring me home to get the pickup.  No answer.  I’d also been dogging a coyote along the way, and I’d seen the ‘yote running along the same path as the deer.  Can’t gut this buck yet.  That’s just inviting that ‘yote in to come and mess up my deer while I’m gone.  Leave it whole.  I walk a couple miles home, get Son out of bed and drive back to the Colfax highway.  We get permission to drive over a planted field to the deer.  No dice.  The frozen mud had thawed enough at the surface that a 4×4 with studded snows can’t get a grip to climb over the hill.  We’re on foot.  We go back home to grab a saw and a sled.

Below; the buck fell about a 1,000 yards from where he was hit, which was out of the frame to the upper right.

Looking closely, I find an entry wound in the deer’s left hind quarter.  Odd.  I could have sworn he was broadside to me when the gun fired, and I know I didn’t pull the shot that much.  And there’s a ball, just under the skin behind the right shoulder, exactly opposite where I was aiming, but I can’t find a corresponding entry wound.  Oh well, I’ll find it when I skin the carcass.  Someone else must have shot this deer before me, which would explain the entry wound in the hip.  That’s plausible, since I’ve been hearing shots in the area all week.  Weird.

Hours later we had the big buck hanging in the garage after getting the workout of the year.  Man, this hunting business is getting more like hard work.  After gutting (in the field) and skinning the deer (in the garage) there was only the one entry wound to be found.  The ball had struck the left “ham” at a shallow angle, passed through the intestines doing very little damage, passed through the stomach, blew a three-finger-sized ragged hole through the liver, punctured the diaphragm, punctured a lung, glanced off a rib and stopped just short of exiting the hide on the right side.  I measured 25 inches of penetration, from a ~180 grain round ball that left the muzzle at ~1,920 fps.  That deer ran about a thousand yards with all that damage.

My best guess is that the buck was all wound up tight, having spotted me, knowing that I’d been following him.  The cow-sized cloud of backlit, white smoke that erupted at extra-sonic speed from the muzzle must have made him jump slightly, changing the angle of impact from broadside to less than 45 degrees.  I calculate he had about a quarter second to move from the emergence of the smoke cloud.  I dunno.  Maybe he wasn’t so fully broadside to begin with as I’d thought.  The “act of grace” neck shot did not penetrate more than three inches, but shattered the vertebra.

Here’s one reason to have children.  They can pull your sled;

 

Observations on penetration and “stopping power”
Starting last season, we’ve shot three deer with the same exact load from the same muzzleloading rifle.  The first shot penetrated an adult whitetail fully, straight through the ribcage, severing a rib fully on each side, from <30 yards.  The same shot from Son hit a smaller deer broadside through the ribs, hit the heart and blew it completely apart, such that you could lay it out like a pancake, and did not exit the hide on the far side.  Less than 14 inches penetration.  Hitting the big buck in the heavy hip muscle from almost three times the distance, the ball went through 25 inches of animal, and the second ball (on the buck's neck) was demolished after about three inches.  The same load (110 grains of Old Black pushing a ~180 grain .495" round ball) penetrated between 3 and 25 inches (a factor of 8.33) depending on shot placement.  Sort of makes you wonder about penetration figures given for defense loads.  It all depends and what's being penetrated, from hide, to muscle, to the liquid chambers inside the heart, to lung and liver tissue that doesn't explode like that heart did.  And stopping power?  Each one of these deer was hit with a 100% lethal shot, and they ran from eighty to one thousand yards after being hit.

We’ve had similar “stopping power” experiences using modern rifles, but never has a modern rifle load failed to penetrate completely, regardless of what it hit inside.  I’ve been wondering whether the stories of recovered, modern hunting rifle bullets are just mythology, but if the differences in penetration can be so great with the muzzleloader they must be fairly large with modern systems too.

(With that I think I’ve outdone myself—- 2,000+ words.  It’s my first nice buck.  Can’t I prattle on and on about it?)

Below; Along the bottom, near that ditch behind the small rise is where the buck fell.  Kamiak Butte is in the distance, top right in the frame.

Below; this .495″ (well, formerly .495″) lead ball traveled 25 inches into the animal.  I’d not believe it if I hadn’t seen it.  I bet I could load it again and kill another deer with it next year.

Yards, Meters and BDC

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So maybe I’m an idiot.  I was out firing a Colt AR-15 HBAR with a Trijicon ACOG scope.  I’d gone the extra step and drilled through the A2 carry handle on this otherwise pristine Colt so as to add the second mounting screw for the scope.  The BDC (Bullet Drop Compensating) reticle has different crosshairs for elevation at different ranges (wind is of course still up to your doping skills).  You zero at, say, 100 using the main crosshair, and your elevation is supposed to be correct at all the other indicated distances.  One comment on that; it would be much better to refine your zero at greater distances, using that other crosshair, say, at 500 using the number 5 crosshair or etc.

Out in the real world though, your targets aren’t placed at nice, even, measured distances, so it gets just a little bit more complicated.  I’d brought a laser with me to do range measurements.  The laser registered a particular target at 385 yards.  Said right there, so it couldn’t be wrong, “385 yd”.  That’s close enough to 400 that I opt for the number 4 crosshair.  Shot went high.  “Not possible– I called that shot dead on.”  Same thing again.  Walking the shots onto the target, I find I have to hold halfway between the number 3 and 4 crosshairs*.  “Crap.  This shouldn’t be happening.  I have nigh on three grand worth of equipment in top condition, the right ammo, and a standard length barrel.  What the hell?”

Some of you will already have figured out the problem (I seem to recall something about an interplanetary probe oblitorating itself on Mars due to a similar error).  The ACOG scope is calibrated in meters and the laser was set to display in yards.  A yard is 0.9144 meters.  In realistic rifle shooting distances, we can simplify that to either adding or subtracting 10% to do the conversion in our heads, and be close enough.  At 385 yards I was rounding up to 400, which made sense, but I was still thinking all in yards.  I didn’t convert.  385 – 10% (simplify further and subtract 38) =  about 347 meters, or close enough to the 350 meter crosshair for this target.  *Ah Hah!

Better yet would have been to take all of half a minute (only because I don’t mess with the settings much and I’d have had to take that long to figure it out) to set the laser to read in meters.

On a nice, relaxing day with a full belly and a Thermos-full of hot coffee (as backup this time) the sun shining and the birds chirping among the beautiful North Idaho scenery, this was more of an amusing lesson than anything serious.  If there is ever a situation in which it really matters, you’ll want to be aware of these things in advance, and have taken the necessary steps already.

Part of my problem is that I fool around with so many different weapon systems, in addition to being an idiot.  How does that saying go?  “Beware the man with only one gun.”  Something like that.  He knows his weapon backwards and forwards, right and left, upside down and every which way, in the dark, summer and winter, and with one hand tied behind his back just to make if fair he’ll still kick your ass.  Hmm.  Maybe there’s a new IPSC stage in there somewhere.

Update: With the low recoil of the 5.56 round and a low power optic, you can usually spot your own hits even at longer distances.  Take that for what it’s worth.

The “stopping power” debate will never end

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John Fogh offers this advice from John Holschen:

Believing that the 5.56 “stopping power problem” is solved by a different bullet and/or cartridge is likely delusional in my opinion.

This statement doesn’t stand on it’s own because I’m pretty sure a 16″ shell from the Missouri is an instantaneous (for all practical purposes) man stopper. Just the muzzle blast will kill. But that’s the nit-picky engineer in me. And besides, Holschen qualifies it as referring to handheld firearms:

The stopping power “problem” is based on the misconception that there exists a hand-held firearm which can instantly terminate hostile behavior (reliably and repeatedly).

But the most interesting part to me was the conclusive evidence that:

…[A] BG was hit 12 times with an AR at a range of 9-12 yds.

  • 10 rounds struck his torso producing fatal damage to his liver, spleen, heart and both lungs.
  • 1 round struck his right femur fracturing same (and starting his fall toward the ground.)
  • 1 round entered through his left eye and destroyed a significant portion of his brain (this was the last shot according to forensics but they noted the BG was already falling at the time this round hit him.)
  • The shooting was captured on both video and (separate) audio recordings. The elapsed time from the LEO’s first shot to his 15th shot (total rounds fired) was just under 5 seconds.
  • During those 5 seconds the BG continued to fight, firing 6 rounds from a .357 revolver.

The LEO fired three rounds per second and got 12 of his 15 shots on target and one of those was a head shot, all while being shot at by the bad guy. Impressive. Had he been shooting a .30 caliber rifle I doubt he could gotten near as many shots on target in that time frame. What this may mean is that in a similar event the .30 caliber rifleman would have put only two or three shots in the target and the BG stopped his attack in the same amount of time.

So which caliber has more “stopping power”? Remember, you can double the effectiveness of any bullet by putting another round through your target.

What does the bullet do?

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One of my more popular posts was Where does the bullet go?. I am somewhat of an expert on small arms exterior ballistics (I wrote Modern Ballistics) but while better than most people on terminal ballistics I usually refrain from saying much on the topic. Greg Hamilton and his colleagues at Insights Training are much higher on that food chain than I am. Although John Fogh doesn’t mention it I know a little bit about the research Insights has done on the topic over the years.

John gives us some of the research results on Terminal Rifle Ballistics.

One mile range proposal

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Via email from Jason comes this link to a proposal for a one mile range in central Washington State.


It sounds like they are talking greater than .30 caliber. My hottest loads with the highest BC bullets in my .300 Win Mag won’t meet the requirement of being supersonic at the target.


For those of you that want to run the numbers yourself assume range conditions of 400 feet above sea level and 75F.

The Sound of Gun Fire from Downrange

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I’ve long been disgusted by Hollywood’s portrayal of sounds.  Sounds in space, sound traveling at the speed of light, and the ridiculous sounds of gunfire made up in a studio.  Even the news services will often do a time-shift, to synchronize the sound of a distant event with the video even though anyone who’s been alive long enough to understand what they’re seeing on TV knows that sound and light travel at different rates.  I just, do, not, get why TV and movie people have to screw up reality so much.  Far from adding anything, it subtracts from the final product.


For example, I think the long delay in the sound of a distant explosion at Boomershoot makes the experience more awesome.  It adds to the perception of enormity.  The movie, “Band of Brothers” is an attempt to show it like it really was, and for the most part they seem to have done a good job.  Not when it comes to sound editing though.  Super-sonic bullets whiz by, “whoosh-whoosh, zip, zip” and so on, and of course the sound always travels at the speed of light.  It’s taking a serious subject and turning it into slapstick.


In the interest of universal understanding, I made this recording of .308 rifle fire from about 380 yards while setting up some rifles for Boomershoot.  The camera is about 20 yards from the targets (yeah, I was holding the camera, but I was behind a hill from the gun and in radio communication with the shooter– completely safe).  Each shot delivers multiple sonic effects or events.  First is the “CRACK-hiss” (mini sonic boom) from the bullet.  Take the sonic boom from a jet flying over, speed it up a few octaves, and you’ll have about the same thing.  That bit is interesting in that it does not come from the gun, but from the bullet.  You have no sense of the direction from which the bullet came.  Imagine standing in the water on the shore of a lake and feeling the wake from a passing boat on your legs.  From that sensation alone, you have no idea of where the boat came from, and little or no information about its direction of travel.  The bullet’s wake, as sound, gives you no more information– just a “snap” that seems to come from nowhere.  Next is the sound of impact, which is only audible in the first shot in this recording.  Then comes the “boom” from the muzzle blast, followed by the reverberation in the surrounding hills and trees.


Note that the reverb almost seems louder than the crack-boom.  That’s due to the AGC (Automatic Gain Control) circuitry, A.K.A. “compression” built into the camera.  The initial crack drives circuitry into gain reduction, and the gain comes back up for the reverb.  To get the relative levels of the events portrayed accurately, I’ll have to take a full-range stereo recorder into the field on another day and use its un-compressed level mode.  If you have some nice speakers (and pretty powerful, as the dynamic range is quite wide) you’ll hear it as if you were actually standing there.  Regular CD audio has a dynamic range of about 100dB, IIRC– close enough.  This recording isn’t all that bad, though.  Crank up the volume, use good speakers, and boost the bass to get the full effect (the mini electret mic on the camera isn’t great for bass response);


Match Hollowpoints – Interior, Exterior, and Terminal Ballistics

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My wife reads a lot of “who dunnit” mystery novels.  The one she’s reading now addresses long-range marksmanship and the use of hollowpoint “match” bullets.  As a person normally 100% uninterested guns and shooting, she had a very good question for me; “Why do they use hollowpoints for accuracy”?  This lead to a very interesting discussion– one uninterested in guns was trying to understand something that few gun enthusiasts understand completely and rarely discuss in such detail.

I had to admit I was at something of a loss.  My best understanding is that the hollowpoint bullet jacket can be manufactured to higher standards of concentricity (the mass being better centered around the mechanical center so as to avoid wobble in flight) and consistency of mass and shape.  That is all true, but exactly why it is true I was at a loss to explain with certainty.  My best guesses are that it has to do with the process of forming the jacket’s shape, and with the insertion of the bullet’s lead core, but I don’t know the actual processes used in bullet manufacturing.

I also told her it was my opinion that since the hollowpoint jacket (having a closed copper base due to the way it’s constructed) allows none of the bullet’s lead base to melt away during the intense heat of firing, it is going to retain its mass, and therefore its consistency of mass from shot to shot, better than the open base of a standard full metal jacket bullet.  I’ve also read that the open-base FMJ can allow the jacket to partially separate from the core at the base under the pressure of firing.  If so, that would certainly alter its flight slightly and at random.

She explained that it was her understanding that hollowpoints were used to cause more trauma inside the target, and I told her that she was correct.  She was having a hard time understanding that there is no direct correlation between the objectives behind hollowpoint “match” bullet designs, and the hollowpoint bullets designed to expand and cause more damage.  This was getting too technical for a layperson, but her interest was piqued by the story she was reading.  I had to explain that hollowpoints designed specifically for expansion on impact have a wide range of designs, operating velocities and applications, and that match hollowpoints have nothing to do with any of that.  The match bullets are only designed for accuracy, with no regard to their effects on a target.

That being the case, one can nonetheless do a little experimentation.  Manufacturers of match rifle bullets usually make a point of telling the customer that they are NOT intended, and should not be used for, hunting.  There is one company, Burger Bullets, that touts their match VLD (Very Low Drag) hollowpoints as hunting bullets.  I’ve been loading Berger 7 mm bullets in 280 Remington for my son’s use at Boomershoot, and since he keeps his rifle zeroed for that load, he has also used the VLDs for hunting.  This particular bullet has a light (read weak) jacket, and while it is an awesome animal stopper, it explodes at high velocity inside the animal due to its light construction and causes major damage to any meat it comes near.  It also tears a large hole in the hide for those of us who keep the skins.  They make a tiny entry wound and a softball-sized exit wound.  That would be OK if the shot placement and angle were ideal because only the heart/lung cavity would be so effected (then too, we like to eat the heart if it’s intact).  Other match hollowpoints have heavier jackets that don’t behave much different, on impact, from a standard FMJ bullet.

Practicing for Boomershoot last week, we found one of our 30 caliber match bullet jackets behind a 2′ diameter rotten, wet log that it had penetrated.  Just the jacket, turned nearly inside-out, with no lead core.  The hollowpoint tip was almost perfectly intact, and so behaved radically different from a hollowpoint hunting or defense bullet.  The bullet had traveled 400 yards, entered and then yawed violently sideways inside the log.  The intense pressure of deceleration caused the heavier lead core to burst out the side of the jacket, separating completely.  The open-sided jacket followed through to drop on the ground just behind the log.  These match bullets were loaded in .308 Winchester cartridges made by Black Hills Ammunition.  We were using 168 and 175 grain, “red box” new loads.  I think the bullets they use in these loads are from Sierra, but don’t quote me on that.  You can call them and ask if you’re curious.

Hey! I know that guy!

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Never mind the 1600+ yard (that is 0.91 miles) hit on a 12″ diameter plate, the guy in the video (you get to see him toward the end) is someone I know. He has been to Boomershoot several times and Barb and I went to high school with his Aunt Shirley. He also used to shoot a lot of IPSC at the same events I went to.





Oh, he is also a gunsmith. I suspect he made the video to show off some of his work as well as his talent.


Thanks to Boomershooter Michael who had the following to say about the video:



Spring is coming, and a not-so-young man’s thoughts turn to . . . Boomershoot. 🙂


Well, close enough for now.

More AP ammo testing

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As planned Caleb and I did some more tests with Ry’s test target. Video and commentary by Caleb.


We went to the Boomershoot site expecting to find little or no snow. We should have called ahead. There was about two feet of snow and we were unable to make it to the Taj Mahal with all our gear. We made do at the first berm. We used a paper target to zero the gun for this range (25 yards) then took a single shot with each caliber at the stack of steel plates at the base of the stump. The bullets at the steel plate went over the chronograph.


This was our setup.



In the following video you see the result of SS-109 and 30.06 blacktip ammo shot at the stack of steel plates each 0.25 inches thick. There is a gap of about 0.75 inches between each plate. Estimated velocity of the .223 bullet at the target is 2600 fps. Estimated velocity of the 30.06 bullet at the target is 2360 fps.


The .223 went through one and almost penetrated the second plate. The 30.06 went through three plates and partially into the fourth.



The .300 Win Mag pushing hand-loaded 162 grain military surplus black tip bullets was able to hit the target with a velocity of about 3315 fps. It went through all six plates:



Update: See also this paper on AP ammo. It’s just the first page (you have to pay for the rest of it) but it’s interesting reading.

Pentration test of .50 BMG AP

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Details of the test, with pictures, are here. Ry stopped by the house yesterday and I got to handle the test target and we talked and speculated about the details of the test results. The next time I go back to Idaho I think I will borrow his target and do the same test with 30-06 AP.

What should I do next?

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My Modern Ballistics for the Field software is essentially completed (as long as there are a fair number of people using it software is never done). And I’m debating with myself as to whether I should start work on a Leftspeak to English conversion website or if I should work on some explosives modeling software.


The Leftspeak project would be easy and fun and only take a few days in my spare time. The explosives modeling software will probably take months but be far more useful.


Any votes?

Modern Ballistics for the field

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I’ve fixed all the fixable bugs in my cell phone/PDA web based exterior ballistics program I announced last November and put it at it’s permanent home at http://field.modernballistics.com/.


Enjoy and let me know if you run across any bugs not mentioned on the Known Bugs page. Suggestions for improvements are also welcome. Send them to “JoeH AT modernballistics.com”.

Where does the bullet go?

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I have worked with the mathematics of exterior ballistics for so long that I sometimes forget the general nature of the path of a rifle bullet to it’s target is not mind boggling obvious. I was reminded of this by an email I received today:



Need a answer: I was told that when shot a 30 cal. bullet goes up and makes an arc to the target, when held level. What happens, say at 100 yards.?


This email caused me to have a flashback to when I was in grade-school (yes Kris, firearms had been invented by the time I left grade-school).


When I was about the fourth grade a friend of mind, Verl (yeah, kids had strange names back in those days), insisted that the bullet would rise after it left the barrel of a rifle. I didn’t believe it and asked how long it took before it when into orbit (or some such thing that pointed out the absurdity of his claim). He didn’t know but asked his dad and came back to school and explained it went up for a while then came back down. My knowledge of and ability to articulate the physics of gravity and moving objects was limited and although I was profoundly unsatisfied with this explanation I couldn’t refute his assertion that it was true.


Later I made sense of it and eventually I wrote a computer programs that accurately predicts the path of a bullet as it leaves the muzzle. I am now much more capable of articulating the physics and will now attempt do so.


If you were to go to the range and instead of shooting the bullet you were to drop it from your fingers you would correctly expect the bullet to immediately accelerate toward the center of the earth and pick up speed at the rate of about 32 feet per second for each second it is in the air until it hit something. It doesn’t rise for a while then start falling. If you take a carpenter’s level to the range and line up the bore with the level such that the bore was horizontal and fire the gun the bullet will drop, relative to the horizontal, from the instant it leaves the barrel. It does not rise and then fall. It also does not fall at the same rate as a bullet you dropped from your fingers but that is another, much more complicated issue that is beyond the scope of this post.


Because the bullet immediately starts falling as it leaves the barrel in order for the sights to predict the impact point they are not aligned exactly parallel with the bore. They are aligned such that when you view the target they line up where the bullet will actually hit after bullet has dropped by whatever amount on it’s travel to the target. If the bore is horizontal the sights are pointed slight down. If the sights are horizontal then the bore will be pointed slightly up. In other words there is an angle between the line of sight and the bore of the gun. I call this angle the “Sight Angle”.


As far as I know I am the first to use the phrase “Sight Angle”. I use this to simplify the setting of the scope for long distance shooting. Most long range shooting instructors refer to your gun having a “Zero” that depends on the altitude, temperature, bullet velocity, and ballistic coefficient of the bullet. This is wrong. The gun is constant with respect to the environment. The drop of the bullet changes, not the scope setting.


Knowing the distance to the target and the drop the bullet makes when it goes this distance we can compute the proper angle the barrel should be with the horizontal to hit a target that is the same distance above the ground as the muzzle of the barrel. This angle is the proper angle required to have the gun exactly compensate for the drop of the bullet on it’s way to the target. This angle is not the sight angle because there is another complication–the height of the sight above (almost always but not necessarily) the bore. For a typical scoped rifle the line of sight through the scope is about 1.5 inches above the center of the bore. I call this the sight height. Using some trigonometry the sight height and proper angles can all be number crunched into a single number that you can dial into your scope such that for any give range and bullet drop you can dial your scope to the proper angle and you have precisely compensated for the drop of the bullet such that where you line the sights up that is where the bullet is going to go (minus bullet inaccuracy, wind drift, and shooter error). This “proper angle” is my Sight Angle. If you know what the environment is and you know the angle of the scope (and its height) relative to the bore you will know where the bullet will hit for any given range.


So, the email asked for what happens at 100 yards. Here are the graphs (generated with Modern Ballistics, which I wrote).


First the drop for a bullet fired with the bore of the gun horizontal. This is for a .308 Winchester shooting Federal match 168 grain bullets at “standard conditions” (59 F, sea level). Yes, I know this graph is confusing. It is not the path of the bullet. This is the distance the bullet has dropped as it traverses from the muzzle to the target. The drop increases the further it travels:



By the time the bullet has traveled 100 yards it has dropped nearly 3 inches. If you point the bore up at a slight angle (4.23 Minutes of Angle to be exact) compared to a scope mounted 1.5 inches above the center of the bore, aim the scope at a target 100 yards the bullet will start out 1.5 inches below the line of sight of the scope. Because the barrel is pointed up slightly as the bullet travels forward it will rise as it travels to the target. The distance from the line of sight through the scope to the bullet at any given range is called the height of the bullet at that range. Hence at the muzzle the height is -1.5 inches. And since the proper angle for a 100 yard zero was dialed into the scope the height at 100 yards will be 0.00 inches as seen in this graph:



So, from the viewpoint of the scope the bullet does rise and then fall. Of particular interest is that there are actually two zeros for this scope setting. There is a “Near Zero” at 49.8 yards and there is the normal or “Far Zero” at 100 yards. At what is called the Midrange, 75.1 yards in this case, the bullet is at its maximum height of 0.2 inches above the line of sight.


So that is the path of the bullet for a 100 yard shot.


It is just my opinion but I don’t think shooting at 100 yards is very interesting with a rifle. The errors involved for temperature changes, air pressure, wind drift, and bullet velocity variations just don’t stack up enough to amount to much at that kind of range. For a .30 caliber rifle I don’t find things particularly interesting until we start shooting targets at 500 yards and beyond. I’m not going to get into all the interesting details because 99.9% of the people will find what I think is fascinating as mind bogglingly boring. But here is a hint of 500 yard shooting. A graph of the height of a bullet, again relative to the line of sight of the scope, for the same rifle and cartridge as above but for a 500 yard target:


Software alpha release

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I have my software project ready for an alpha release (feature complete, but there are known bugs which must be fixed before release).


This was designed for cell phones not a desktop. It will work on desktop and laptop computers but whenever a user interface design was a trade-off between a desktop user and a mobile user the mobile user was given the advantage.


The software is a web based exterior ballistics calculator and can be found here: http://test.joehuffman.org/ http://field.modernballistics.com.This is much different that Modern Ballistics but uses the same algorithms and concepts. This web based version is for use in the field. Example, while at Boomershoot you can input the exact ranges and inclination to a set of targets combined with the weather conditions to get the scope setting needed for one shot, one “kill” hits on the boomers. I plan to have it running on a local server at Boomershoot 2009 so cell phones (and laptops) with WiFi support can get really fast results even with a heavy load of users.


I’m also thinking that maybe for Boomershoot 2010 I will have a weather station on site that will update the conditions for a special version of the software in real time.


Known bugs:



  • The help page is for the desktop version not the web based version.
  • If the bullet velocity at the target is less than 1400 fps all parameters such as elevation angle, windage, time to target, etc. are in error.
  • Some optimization for response time and load handling should still be done.

All data is stored in cookies on your device. This means the website does not need to save the data on the site in order to save your data. The downside is that all your input from the desktop does not show up on your cell phone or if you get a new cell phone the data will have to be reentered.


At this point I’m mostly looking for user interface and device compatibility issues. Does it appear to work on your Blackberry? Does it work on your iPhone? Is the user interface easy enough to understand and use? If you have problems with your cell phone try using it on a desktop computer to make sure you are using the software right before assuming the cell phone is having problems with the website.


Leave comments here.


Thanks for your feedback.

Hitting the 957 yard target

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Last Saturday most of the gun bloggers at the Rendezvous went to the range. Other reports and pictures from range day are here:

Yes. As nearly everyone else noted, it was on the cold side of comfortable. The temperature was about 35 F and when we arrived the winds varied from 10 to 20 MPH.


Derek deals with the cold and wind.

These were not the best of conditions for long range shooting but this range is for long range shooting and I wanted to do some long range shooting. I had not shot my .300 Win Mag since the year before at this same range. This range has targets out to nearly 1000 yards and this, more than anything else, is why I wanted to go to the Rendezvous.

Traction Control brought his Barrett .50 BMG and was setting up at the very end bench. This minimized the impact of the vicious muzzle blast on other shooters. I set up on the empty bench next to him but stood behind the line when someone was shooting the .50 to avoid the vicious muzzle blast. This extended the time for my set up as I measured the wind speed, wind direction, air pressure, the inclination to the various targets, and used my laser range finder to get the exact range to each of the targets. I was still making measurements and taking notes as everyone else went through two cycles of shooting and shutting down the range to change targets. I then used my HP-41CV calculator running a special version of Modern Ballistics to compute the necessary sight angle between the scope and the gun for the elevation. I didn’t bother with measuring the incline for the targets at 523 yards and under because they were all less than 8 degrees and the resultant shift in scope settings would be less than 0.1 MOA from assuming no inclination. By the time I was finally ready to shoot there was very little wind from side to side so I didn’t bother to run the numbers through the calculator.

Here are my notes:

October 11, 2008

Apparent Elevation (based on air pressure): 3500′
Wind: 10 to 20 MPH 45 degrees

Target

Range (yards)

Incline (degrees)

Sight Angle (MOA)

Paper

197

0

4.87

Plate 1

342

–

7.83

Plate 2

412

–

9.51

Plate 3

523

–

12.38

Plate 4

637

8

16.63

Plate 5

957

11

27.19

Having done all this I finally took my first shots at the paper target:


Five shot group at 197 yards at the upper A-zone of a USPA target.

I should have put a orange target dot on the center of the ‘A’ to have a better aiming point. It was difficult to get the cross hairs centered on the outline as I couldn’t see the ‘A’ itself. As it was I just concentrated on the horizontal because I was uncertain as to my windage zero but not my elevation zero. I expect most of the vertical was my fault and not the gun and/or ammo. Still, it was a less than 3/4 MOA group and I was satisfied with it.

I adjusted my windage zero and took some shots at the closer plates. I connected every time and was rewarded by seeing the plate swing and hearing a loud “thwack-clang” sound. I then asked Phil to spot for me as I adjusted for the 957 yard plate. The plate was difficult for a lot of people to find. Here is the context as seen through a 300 mm (think of it as 6X telescope) camera lens:


Plate and drum are in the upper left quadrant.


Close up of the 957 yard plate and 55 gallon drum.

A 55 gallon steel drum is about 22″ x 34″ and based on that the plate appears to be about 30″ x 16″. My mil-dot reticle estimates agree with this. The wind was very low but even a 3 MPH wind would result in a miss if I aimed dead on at this range. I waited until the wind appeared to be zero and pulled the trigger. Phil reported it hit just a bit to the right of center and dead on for elevation.

A first round hit at nearly 1000 yards. The geek wins!

The rest of the day was anti-climatic for me. I shot at the 957 yard plate a few more times but I ignored the wind and got hits only about half the time. I shot 10 rounds out of Traction Control’s .50 (I brought my own ammo) and got 7 out of 10 hits on the drum. The .50 has a much better BC (1.05 on the 750 grain A-MAX versus 0.533 on the 190 grain Sierra Match Kings I was shooting) which helped on windage but I suspect that gun didn’t have the inherent accuracy because the target was bigger and I got essentially the same hit ratio.

I emptied a magazine (four rounds) into each of the closer plates and knocked down the 523 yard target with my last shot. As it appeared everyone remaining from the Rendezvous was waiting on me I packed up and left. I was done as soon as I got the first round hit on the 957 yard plate. That was all I was really interested in anyway.

By the end of the day the apparent elevation had changed to 3700 feet but I ignored this as it made only about 0.1 MOA difference at 957 yards. Had it warmed up 10 degrees to 45 F that would have made a difference of 0.28 MOA in the same direction and I would have taken two clicks off of the scope setting for the most distant target to account for both.

Update: The picture below is from last year and the target is out of focus but it does give a sense of the size of the target as seen in a 14X scope. The drum is 2.5 Mils to the right of the plate which is almost centered in the crosshairs.


2007 view of the 957 yard target at the Reno Range.

Packing for the Gun Blogger Rendezvous

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Kevin is leaving tomorrow evening. Barb and I are packing tonight. Our plane leaves at noon tomorrow but we will be in Tonopah until Friday which means we will miss out on the super secret event on Thursday evening.


The gun stuff I’m packing includes:



  • Gun Blog 45 and 200 rounds of ammo
  • STI Eagle 5.1 and 200 rounds of ammo
  • Shot timer
  • Spotting scope (I hope I can find it!) and tripod
  • .300 Winchester Magnum and 100 rounds of ammo
  • Laptop computer with Modern Ballistics (yeah, I’m a geek)
  • Some cleaning supplies

Anything I’m missing that I can legally take on the plane (no, I won’t be bringing my chemistry set) and would be nice to have on the range Saturday?


Update: I can’t find my spotting scope so I’m not bringing the tripod. I am bringing my laser range finder and a pair of good binoculars.

Educating the media on body armor and rifles

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Earlier today Say Uncle sent me an email asking if I could help out a reporter looking for “someone of authority” to address the body armor versus deer hunting ammo issue. I know a lot more about exterior ballistics (I wrote Modern Ballistics) than terminal ballistics but I’m not totally ignorant of it either. So I agreed to “look up a few references” for the guy.


My email, with very minor edits, to the reporter follows. His email response indicated he was happy with my answers.




Say Uncle asked that I address your “deer ammo going through body armor” story. I’ll address it as best I can but strictly speaking I’m not an expert. I’m a very well informed hobbyist.


Although there is occasional some controversy over the National Institute of Justice testing procedures and standards they are still “the standard”. You can read their standard here.


Their main page on Body Armor is here.


Probably the part that is most relevant to your issue is the body armor classification. This can be found in section 2 starting on page 17. The basics are that body armor is classified according to the level of protection it provides. Those classes are, in order of increasing protection level:



  • Type IIA (9 mm; .40 S&W)
  • Type II (9 mm; .357 Magnum)
  • Type IIIA (.357 SIG; .44 Magnum)
  • Type III (Rifles)
  • Type IV (Armor Piercing Rifle)

Most law enforcement officers wear type II or IIIA. Higher levels of protection require metal or ceramic inserts which increase the weight, bulk, and the body heat retention. See also Section 6, Selecting the Appropriate Level of Protection in this document. At some point in the tradeoff between comfort and protection the police officer will stop wearing the armor on an everyday patrol. In a high risk entry/arrest situation they are more likely to upgrade to type III armor if it is available.


The problem certain well intentioned politicians get into is that they don’t realize the body armor problem is as much a velocity problem as it is a bullet construction problem. Certainly sharp pointed Teflon coated tungsten carbide (a very hard metal used for metal working tools) bullets will penetrate a higher level of armor than a blunt nosed soft lead bullet. But that only goes so far. Increasing the velocity of the bullet by a few hundred feet per second will overcome the inferior construction in most applications. Rifle bullets are much faster than common pistol bullets. The typical handgun bullet is on the order of 1000 fps. A typical modern center fire rifle bullet leaves the muzzle at a velocity on the order of 2500 fps or greater.


I’ve done some informal testing with the 30-06 rifle on an engine block. The Speer Reloading Manual says of this rifle cartridge, “It is safe to say that the 30-06 Springfield is the best-known and most successful centerfire cartridge ever developed.” In a typical hunting load (see http://www.federalpremium.com/products/details/rifle.aspx?id=260) at 100 yards from the muzzle the bullet is still traveling at over 2600 fps. The tests I did were with a target cartridge and bullet (http://www.federalpremium.com/products/details/rifle.aspx?id=148). At the muzzle this bullet is traveling at about 2700 fps and is still going at over 2500 fps at 100 yards. I was shooting into the side of a six cylinder car engine from the early fifties from about 50 yards away. This was a very heavy engine block compared to today’s cars yet the target bullet would penetrate half way through the block penetrating the water jacket, one side of a cylinder and frequently one side of a piston. A very high velocity (1350 fps at the muzzle) 9mm bullet shot at the same engine block only knocked the rust off of the metal. It did not dent or crack the side of the engine.


It is a very different problem to stop a rifle bullet than to stop a handgun bullet. Although it isn’t quite this simple you can think of it as an energy problem. The energy of the projectile is proportional to the mass of the bullet times the velocity of the bullet squared. That is E = m V2. The mass of a common hunting bullet is on the order of 150 to 180 grains. The mass of a pistol bullet is on the order of 125 to 200 grains with the heaver bullets moving much slower than the lighter ones. The rifle bullets typically are moving about 2.5 times as fast as the pistol bullets. Hence they will typically have about 2.52 or about 6 times as much energy as the pistol bullet.


Even the ancient 30-30 Winchester cartridge has a muzzle velocity of nearly 2400 fps with a 150 grain bullet (http://www.federalpremium.com/products/details/rifle.aspx?id=28) which will cut through the typical concealable body armor worn by law enforcement on a daily basis. Higher end rifles for larger game such as, the still very common, .300 Winchester Magnum with a 165 grain bullet (http://www.federalpremium.com/products/details/rifle.aspx?id=592) have muzzle velocities of over 3000 fps. Run the numbers on that and see the sort of problem the body armor is facing.


Hence, the NRA claim that outlawing ammunition on the basis of its ability to penetrate typical body armor would result in the banning nearly all common rifle hunting is true. It is possible the politician did not have that intention but that would be the result.


That is probably more information than you really wanted but I hope it answers your questions. If not or if you have any further questions please let me know.