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.

Polymer tipped bullets

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I have often wondered about the polymer tipped bullets from various manufactures. I have read of people seeing wisps of lead on paper targets that apparently came from lead tipped bullets that melted in flight. If the heat at the tip of a bullet can melt lead then the type of plastic used for bullet tips needs some serious consideration. But, I figured the bullet manufacturers knew a lot more about this than I did and had it all under control.

It turns out this was not the case:

the Hornady engineers observed a convex hump form when charting the new bullet’s drag. The hump was relatively small and usually occurred within the first 100 to 200 yards of flight, and following the hump the drag curve returned to its expected concave climb and drop. The irregularity may have been small and short-lived, but the shift from concave to convex, and back again, seen on the Cd vs. Mach Number graphs could only have one explanation: The bullet itself was changing shape in flight.

It did not take long for the Hornady team to realize it was not the whole bullet changing shape, only the non-metal component—the polymer tip.

The solution, of course, was to find a new polymer:

New polymers were tried and tested, and one was found that met the company’s criteria. With the new material, the Heat Shield Tip was born. Molded as precisely and consistently as previous polymer tips, the Heat Shield Tip boasts glass transition and melting points hundreds of degrees greater than the previous generation’s—475° F and more than 700° F, respectively.

This resulted in higher ballistic coefficients (BCs) which translates into less windage and drop.

My favorite bullet for .30 caliber long range shooting has been the Berger 210 grain VLD bullet. It has a G1 BC of .621. The Hornady 30 Cal .308 208 gr ELD™ Match bullet has a BC of 0.670. From 700 yards away with a .300 Win Mag with Boomershoot conditions this increases the velocity by 60 fps and decreases the drop by 2.6 inches. This isn’t enough of a difference to throw away my existing bullets but I think this is what I’m probably going to replace them with.

Powder puff load report

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As I reported last week I was trying to make some very light loads in .40 S&W for new shooters. I made up 200 rounds with the 180 grain Rainier FP over 3.9 grains of Bullseye with an OAL of 1.131”. On Christmas day, while at Brother Doug’s place I shot some over the chronograph. This load yielded a mean velocity of 825 fps (standard deviation of 9.6 fps) for a Power Factor of 148.5. The expected result was 800 fps for a PF of 144. Not too far off from the actual. I would have preferred it be on the low side instead of the high side but still, not bad.

My typical handloads run about 940 fps for a PF of 169 or so. 180 grain factory loads run about 1000 to 1025 fps for PFs of 180 to 185. Hence these new loads are have about 80% of the momentum of a factory load and a little under 90% that of my usual handloads. This is better but I would like to do better still.

While in Idaho this weekend I bought a pound of Clays from Alan B. I loaded up 100 rounds of the 180 grain Rainier FP over 3.0 grains of Clays. I ran them over the chronograph today. Remember that the reloading manual said to expect:

180 grain bullet over 3.0 grains Hodgdon Clays => 727 fps with 131 PF

The result was 728.11 fps (standard deviation of 8.8 fps) for a PF of 131.06. Wow! That was freaky close compared to the expected result.

That gives me a load with about 78% of the momentum of my typical handloads and a little over 70% that of a factory load. And get this, it’s right at the same momentum as a typical 147 grain 9mm round but with a muzzle velocity that is about 100 fps less. That is even less velocity than a typical 230 grain .45 ACP. With such a low muzzle velocity it is much more of a push than a “snap” on the recoil. It’s a very comfortable load to shoot.

Thank you Mike B. and Alan B. for the Clays powder. That made a big difference.

I was thinking ahead to how to make a self-defense load with similar recoil properties and found that Speer makes a bullet they call Gold Dot Short Barrel for good self-defense characteristics with lower velocities. This sounds like just the ticket for Cherie. We have another range trip planned for the end of next month to do some more training and test out the new loads.

Powder puff

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I decided I should make some low power loads in .40 S&W for new shooters that are recoil sensitive. “Powder puff” loads. After exploring lots of options I came up with these as the best possibilities. From Hodgdon:

135 grain bullet over 4.0 grains Hodgdon Clays => 940 fps with 127 PF
180 grain bullet over 3.0 grains Hodgdon Clays => 727 fps with 131 PF

Typical factor loads are in the 180 to 190 PF range. So this should be about 70% of the recoil of factory loads.

The difference between power factors of 127 and 131 with equal weight bullets is probably undetectable in your hands. But because the 127 PF load is with 135 grain bullets versus the 180 grain for the 131 PF you get a much different recoil impulse. The lighter bullet is going over 200 fps faster and that means the recoil impulse is much shorter and hence will feel sharper. So, the 180 grain load looks like the winner. That nice because I have lots of 180 grain bullets around.

But I don’t have any Hodgdon Clays powder. I started looking online. Nothing.

[Heavy sigh.]

So what other options do I have and do I have any powders that could come close to this? I have an older version of the Hornady Handbook of Cartridge Reloading and they list Bullseye powder for a mild load.

180 grain bullet over 3.9 grains Bullseye => 800 fps with 144 PF.

I have some Bullseye powder left over from my explosives experiments with it about 1996 or ‘97. This would be a good opportunity to get rid of it. This isn’t as good at the loads with Clays but it is still less than 80% of a factory load.

I loaded up 20 rounds Saturday and went to the range to see if it would cycle my gun and if it was accurate. I used some 180 grain Rainier truncated cone FP bullets I had won at a match this summer. I have had problems with the accuracy of Rainier HPs once I went beyond about 7 yards so I was a bit skeptical of these too.

The ammo cycled and fed well in two different guns. The accuracy wasn’t great at 7 yards but it was far better than new shooters can manage. And I don’t have them shoot beyond that distance anyway.

Today I loaded up 180 rounds using some nickel plated brass I had laying around. I used the nickel plated so I could easily keep track of it being “special”. I’ll load up the remaining 300 Rainier bullets in that configuration in the next couple of days.

It turns out the loaded ammo looks particularly pretty. Barb said it looks like Christmas:

IMG_5238Web

I suppose it does. We have Powder Puff Christmas ammo.

Shooting the Glock 43

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Apparently it’s a thing. People often talk of shooting their guns, but it never quite made sense to me. Why shoot a perfectly good gun?

IMR powder recall

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IMR Powder, a subsidiary of Hodgdon Powder Company, announced a product recall and safety warning for its IMR 4007SSC rifle cartridge reloading powder. The company says certain batches of the powder are unstable and can spontaneously combust.

Yikes. Spontaneous combustion is a rather undesirable characteristic in a gun powder. I don’t remember seeing 4007 SSC in my manuals, and don’t have any. I use several other IMR and Hodgdon powders though. They’ve always worked well, and my family armory has yet to explode.

Firing 40 S&W in a 10 mm Glock

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Over at The Truth About Guns.

Pretty interesting. I was confused for a bit though, until I realized that by “excessive headspace” the author really means “excessive case length” which would result in inadequate headspace. Using the shorter 40 S&W cartridge in a 10 mm barrel results in excessive headspace, so it’s a sort of Opposite Day article in that regard. It’s a well-written and interesting article otherwise.

The greater implication, at least for Glock shooters, is that you can go ahead and trim your brass at or below minimum spec and the gun will run just as well and possibly better. This would explain some of the commercial ammo I’ve seen, which has what appears to be a roll crimp rather than the prescribed taper crimp. That COULD result in a dangerous situation, as the crimp opens up across the chamber shoulder. So long as the case is short enough though, that the case mouth never touches the chamber shoulder, everything’s fine and dandy.

I’m one of those people who regularly checks finished rounds by plunking them down into the chamber (barrel removed from gun) to check for headspace. That’s a fine idea for several reasons, but this article puts all that into a rather different light when it comes to Glocks.

I have some 40 ammo lying around, though I don’t own any guns chambered for it, so now of course I’ll have to try it in my G20.

As an aside; I wish we could get past the little, political/legal/social dance we often perform when it comes to disclaimers. The author of that article asserts that using 40 in a 10 is actually safer than using 10 in a 10 or 40 in a 40, but still feels the need to dance the “Don’t try this at home, Kids” dance. I understand how this social twitch came about (I witnessed the whole thing) but really you can stop any time you like.

Pressure signs

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It seems to me that the process of reading pressure signs in your brass and primers, as they tell us in the loading manuals, can be a bit ambiguous. In this instance however it was rather obvious.

Pressure signs

Too much pressure?

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Words still mean things II

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When writing a review on a firearm, some ammo, or an optical sight, etc., it is probably not a good idea to say that you had “zero issues” or “zero problems” or “zero failures” with it. I’m going to be left wondering exactly what these specific zero issues/problems/failures were, and why you’re not telling us more about them. If you had “no issues” then it would be best if you put it just like that. “Zero issues”, on the other hand, are a whole different subject, and they are potentially very frustrating.

(for those of you who aren’t part of the gun culture, your “zero” is that particular adjustment, or set of adjustments, of your sighting system that puts your bullet right on target at a specific distance when using a specific load [often under specific atmospheric conditions])

Must be at least six inches

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Height over bore, that is.

I’ve only half jokingly mocked other “future weapon” designs in the past, saying that the trend is toward an ever more clownishly high sight axis. My educated guess is that this is in fact a psychological problem.

With the lower velocity of the grenade/shotgun, it would make actual sense to put it on the bottom, with the flatter trajectory rifle barrel closer to the sight axis.

The new terms like “Soldier integrated such and such” (which obviously turn ordinary warfare into something totally new and different) are also the result of psychological problems. Years ago, while reading one of the supposedly big cheese U.S. military publications, I found that such a thing as an “army” is, technically speaking, no more. No, ladies and gentlemen; we now have a “Soldier-Centric Force Structure” instead, don’t you know, which no doubt changes EVERYTHING.

The advantage you see is that people who have actual experience in stuff are no longer needed, and can therefore be safely and conveniently brushed aside. Who needs an Army General when you can have a shiny, new, Soldier-Centric Force Structure Command and Control Engineering Specialist? Hmm? Was General Patton a Soldier-Centric Force Structure Command and Control Engineering Specialist? I don’t think so. All he did was lead an Army to kill a bunch of folks and break things. Feh!

And who needs a stupid old rifle when you can have something that looks like it came out of a bad Sci-Fi movie written by an ignoramus, and having the ergonomics of a cinder block?

28 Nosler

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175 grains at over 3,000 fps. Owww!

I’ve been using the Berger VLD (Very Low Drag) 7 mm bullets which have an amazing ballistic coefficient for the weight, and do very well in the 280 Remington A.K.A. 7mm Remington Express cartridge. I’m sure they’d do very well in the new Nosler cartridge also.

Is this better?

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A few days ago I posted this image and asked “What does this look like?”

IconicScreenShot

I have updated the image to this:

FieldBallisticsIconicSample

In addition to tracing over the top of an image of an actual supersonic bullet in flight I simplified things some. I have a strong tendency to dive deep into details when it isn’t necessary and even when it is counter productive. This represents a lot of restraint on my part.

As some people guessed this was for an update for my ballistics program, Field Ballistics, for Windows Phone. There are some other changes as well. The most important of the changes:

  • Elevation measurements are expressible in mils as well as MOA
  • Native support in various resolutions for Windows Phone 8.0.
  • When the “Wide Tile” is pinned to the start page it show the current conditions, cartridge, and target selected.
  • All of Hornady’s match ammo has been added to the “Factory” cartridges.

If you have it installed on your Windows 8.x phone it may have already updated automatically. If not then go to this link to update.

What does this look like?

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IconicScreenShot

Ignore the red color. In use that part of the image could be green, blue, yellow, brown, pink, whatever. The white part is supposed to be an icon representing something.

The thing it is supposed to look like and what I suspect it looks like to many people is “below the fold”.

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Online version of Field Ballistics

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About a year and half ago I upgraded my Windows hosting service from ASP.NET 3.5 to 4.5. This broke http://field.modernballistics.com.

I checked log files and, as I suspected, almost no one was using it. So I didn’t bother to fix it. I was using a beta version of Field Ballistics (or maybe even released it) and it was so much better that I didn’t even use the web version myself.

Today someone at a manufacturer of airgun pellets sent me an email saying they really liked it (I think they were referring to that version, English isn’t their native language) and wanted to know how much it would cost to support them. I asked about what sort of support they needed and then poked around on my website some. It turns out it was trivial to get it working again. So… in case anyone is interested here is a mobile friendly web based exterior ballistics calculator intended for use in the field.

Shooting a rifle upside down

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Ry pointed out this thread to me on ARFCOM. Probably many people will want to stop at the picture and move on after that but the more interesting part to me is solving the sighting problem.

UpsideDownRifleShooting

Here is my thought process on the problem:

The drop is the same regardless of the gun orientation. Keep in mind that drop is independent of point of impact (POI) relative to point of aim (POA).

To solve this problem in general look up the drop for this range on the ballistics table for your ammo.

With the gun zeroed for this range the barrel is angled up such that it compensates for both the drop and the height of the sight (Sight Height or SH) above the bore.

Suppose the drop is 2 inches and the sight height is 1.5 inches. Hence the angle of the barrel is such that the bullet rises, relative to the muzzle, 3.5 inches between the muzzle and the target.

When you invert the gun you have the angle of the barrel giving 3.5 inches additional “drop” to the gravity induced drop for a total of 5.5 inches.

But you have the sight below the barrel which means you “get back” twice the sight height of the total. So the gun will be shooting -5.5 + (2 x 1.5) or 2.5” low.

Hence, the general solution for a gun zeroed at a given range when you turn it upside-down it will have a POI of:

POI = POA + SH – 2 x Drop

Or probably more useful is the POA relative to the POI:

POA = POI + (2 x Drop) – SH

1000 yard shot with 9mm

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Update: From the comments I discovered Miculek used a 400 yard zero for his revolver, not the 200 yard zero I hypothesized. I have updated the post accordingly.

The other day Say Uncle posted this video of Jerry Miculek shooting at a balloon from 1000 yards away with a 9mm revolver:

First off, as Rivrdog noted, he didn’t hit the balloon. He hit the steel and the splatter from the bullet fragments popped the balloon.

Second, I decided to run the numbers on those shots. Using Modern Ballistics, the bullet Miculek said he used, with a muzzle velocity of 1000 fps (Hornady factory ammo with a four inch barrel is 975 fps but I added some extra velocity because Miculek probably has a longer barrel and a custom load), with a standard deviation of 10 fps, a bullet delivering a five shot group size of 1 MOA under ideal conditions, a wind estimation error of 0.2 MPH, sea level, at 59F, and a 400 yard zero. We end up with the following results.

The bullet took 5.11 seconds to travel the 1000 yards. It reached a height of 110 feet at 583 yards from the shooter. It arrived at a velocity of 377 fps.

This first graph shows the height in inches from the point of aim. At the target the bullet is hitting over 2900 inches low. That is over 240 feet below the point of aim!

Drop10To1000

In this graph the rate of descent at the 1000 yard mark is shown. That is nearly 11 inches of additional drop for each yard of travel.

Drop990To1010

Here we have the odds of getting a hit if the shooter knew the exact ballistics and compensates perfectly for every shot. The random variation of the muzzle velocity, wind variation (Gaussian distribution with a standard deviation of 0.2 MPH), and inherent variations in the bullet contribute enough error that only about a third of the bullets would hit a target 30 inches wide and 50 inches tall.

TargetView

The image below is what the shooter would see with a red-dot sight shooting a tracer bullet with the same drag. I added some wind to make the perspective a little better. At 1.6 yards the bullet crosses the near zero and you can see the red-dot of the sight just before the track of the tracer starts. The tracer ignites at 2 yards. Everything is to scale so change the size of the image such that the base of the 9mm bullet looks the same in the image as a 9mm bullet would at 1.6 yards and you can see what the 30 x 50 inch target would look like at 1000 yards.

TracerView

Jerry is at the peak of human shooting ability but he had some serious luck on that shot.

Windows Phone app reviews

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My two Windows Phone apps have some reviews now. All are five stars!

For As the Crow Flies:

  • by Antonio
    5/18/2014

    Thank you for this app. Useful for me as a firefighter because I can only live a certain distance from the firehouse “as the crow flies” so this app very useful. Simple but worked perfectly.

  • by Kevin
    4/12/2014

    Very accurate, easy to use.

For Field Ballistics:

  • by Bryan
    5/1/2014

    Seriously a cool app for shooters.

“Messin’ around shooting” with carry pistols

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My friends and I, as a natural matter of course, sometimes try our carry or service pistols at 100 or even 200 yards. It’s always seemed to me an obvious thing to try. Why wouldn’t you?

And so when Oleg and I were out “messin’ around shooting” at various rocks, dirt clods, sticks and whatnot at various random distances, we did some 100 yard pistol shooting with our carry pistols (a 9 mmP and a 10 mm Auto).

I haven’t commented on this phenomenon before, but I’ve noticed that the point of hold for 100 yards with a Glock 20 isn’t much different from that at 25 yards. It was when Oleg, without any prompting, made the same observation regarding his 9 mm carry pistol that it occurred to me to say so in a post. Well here it is.

Oleg was striking a roughly 8″ square plate at 100 yards with successive shots from his 9mm Glock.

I don’t know what utility this sort of pistol shooting might have in defense, but it is good to know you can do it.

Cut lead bar verses round ball

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I’d not heard of cut lead bar being used in lieu of ball. The use of “findings” in a fowling piece or a blunderbuss, sure, but not this. Interesting.

If you can melt lead or a similar metal or alloy (and who can’t?) and pour it into a slot between some boards, you have buckshot for your scattergun, or bullets for your “smooth rifle”.

I wouldn’t try it on the line at Boomershoot though. Well OK I might, but I wouldn’t expect any detonations, much less hits, from 400 yards.

1939 LA County sheriff’s revolver club

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From an e-mail.

The PC police would of course disapprove of the cigarettes and cigar. OK they’d disapprove of everything.

Also they handle lead with their bare hands at the range, shoot stuff out of other people’s mouths and ears which our litigious society now largely prevents, and they still for some reason thought the human heart was all in the left side of the chest. It appears that the price of their cast lead bullet reloads was a penny per round (presumably with the deposit of your spent brass).

They had someone else to clean your gun for you. That I do not approve– It’s not only elitist, but dumb from the standpoint of being able to understand and monitor the condition your own hardware. You should clean your own gun as an integral part of the craft.

They did have rotary, progressive loading machines.

I understand the desire for efficiency at a range, and of having some kind of standards for evaluating the skills of your deputies, but the highly controlled (and therefore highly limited) nature of the training/practice experience at such a range leaves me somewhat cold. I suppose it makes me something of an outlier, but I think you should to get out and simply “play” at it now and then, making up your own scenarios, picking non-standard targets at un-measured distances and so on. I’ll call this “messin’ around shooting”.

I once had a retired LA cop (which means he should very well know better from more than a little personal experience) tell me that his 45 ACP could “shoot through an engine block”. When I got back into shooting after being a hippie for a while, one of the first things I did, of course, was to try various calibers on an old chainsaw at a friend’s house. A 9 mm Para would break the aluminum fins off the cylinder, a 10 mm would strip the fins down clean, and a 7.62 x 39 would punch through the light aluminum and severely dent or tear the steel parts. There’s no way your 45 is going to “shoot through an engine block”. The messin’ around shooter already knows this from direct experience.

So while the gelatin testers, the organized range shooters and the gun magazine readers are talking about the performance of this or that bullet or load, the hunter who does his own butchering, and the messin’ around shooter, are often scratching their heads laughing at them.

I know people who are far more concerned about keeping the grass at the range looking nice than having year-round access for shooters, and they hate people like me. If it’s your own private club and your dime, fine.

Man; I got a little distracted there, huh?

Ammo for 3-D printed guns

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The plastic guns being made have been tested with conventional ammo intended to be fired in conventional guns. Why not load up some low pressure rounds specifically intended to work with the plastic guns?

Even if the bullets had muzzle velocities half that of conventional guns you aren’t going to get volunteers to be bullet backstops. Choose a common cartridge which already has a fairly low pressure then tweak the bullet weight and powder charge to get something that the plastic is much more capable of handling.

Here is a list of max pressure recommendations in PSI for various cartridges with the obvious high pressure cartridges removed:

380 Auto 21,500
25 Auto 25,000
32 S&W Long 15,000
38 Auto 26,500
38 S&W 14,500
38 Special 17,000
44 S&W Spl 15,500
45 Auto 21,000
45 Colt 14,000