by Jim Higginbotham

Bullet Penetration Tests

Backyard Ballistics May Suprise You

When I was a young tadpole growing up on Hopalong Cassidy, Gene Autry and Roy Rogers westerns, when the guy in the white hat shot the guy in the black hat the bad guy would wince and fold slowly – that is unless the good guy decided to be magnanimous and just shoot the gun out of his hand. Later westerns and cop shows got a lot grittier and you saw a lot of blood and people being blown over backwards. Blown over backward has become the modern movie standard in most cases now, and third party tales on the internet about as to the impact power and “stopping power” of the various combat handguns with varying loads.

Well, it turned out that whatever those early movies lacked in good examples of gun handling they had the right when it came to the actual effect of a handgun bullet hitting a human subject. The truth of the matter, friends, is that bullets don’t blow up people nor do they physically knock them over backwards. Not to say that people cannot react violently at times to being shot, but this depends on exactly what is hit inside the body, and the mental and physical state of the subject being shot. Small animals may react dramatically to this impact but things that weigh 100 lbs or more often do not show any immediate reaction – other than to keep fighting or run faster.

Now this is not another article on 9mm vs .45. It is not about “stopping power” per se, but we all need to accept that the illusions we see on the silver screen are just that – illusions and for entertainment purposes. If you expect your .44 Magnum to bowl people over with a hit to the midsection you may be in for a rude and fatal shock!

So, would I say that caliber or “power” do not matter at all? I cannot bring myself to say that. I see a difference in cases that come across the desk and in the hunting fields, but that difference is subtle, not so drastic that you can say unequivocally that caliber A is so much better than caliber B that if you carry A you cannot go wrong or that B is a silly choice… within reasonable parameters.

This article is about the fact that you need to test the ammo you carry and make sure it is living up to the expectations you have for it – so long as they are reasonable expectations. After doing this for decades, and having tried many theories out I have come to accept that the more I learn the less I know. But there are a couple of things in which I am fairly confident. One is that what you hit inside the body is far more important than what you hit it with. Though, certainly, your caliber and load choices can affect whether or not the bullet actually gets to the internal target you intend to hit. I would warn against using that as a license to carry the smallest thing you can carry!

Remington .357 Magnum 125gr JHP, 4” Barrel. Note slight dent in wood. Expansion .57”

This makes two things paramount in ammo selection; Penetration (because the well aimed bullet that does not reach the intended target is of marginal use) and the size hole it makes. If the intended target is the Central Nervous System – admittedly a difficult target to locate within the body and hard to reach – then the size of the hole might not even matter, unless it was a very near miss with a smaller caliber which could have been a hit with a larger one. But remember, the difference between the diameter of a .38 and .45 is only a tenth of an inch. The bigger bullet that misses or penetrates one inch shy of its goal, is inferior to the little bullet that achieves that goal.

Now there are plentiful sources of ballistic information out there, indeed perhaps too many. The fly in the ointment is that most of the information is gathered by shooting into some artificial medium, usually 10% Ordnance Gelatin. This is because you just can’t practice on real subjects. The authorities take a dim view of shooting thousands of people just to find out some ballistic properties. The main problem with artificial, homogenous materials is that… well… they are artificial… and homogenous, flesh and blood is not.

Gelatin, when used properly, this is a very consistent medium and that the data acquired using it is quite useful, especially if one uses the entire F.B.I. protocol. However, it is still artificial. The downside is that it is expensive and it is hard to work with consistently for those of us who do not have a climate controlled lab. It is great for ammo manufacturers and large research organizations.

So, why do we need information other than that produced by these manufacturers and organizations? Because different ammunition performs differently in different guns, and even in different batches, depending on the manufacturer.

The last two boxes of the very well respected .357 Magnum 125gr JHP load which is supposed to give 1450 fps from a 4” barrel gave just 1270 fps from my 4” S&W Model 19 – this happens to be a gun that is particularly “fast” (shooting bullets over the chronograph much faster than most factory specs). These boxes were from two different lots. On yet another occasion two different lots of a load from a premium ammo company gave as much as 200 feet per second difference in the same .38 +P loads when fired over the PACT chronograph from the same gun on the same day.

Cor-Bon .38 Spl +P 110gr DPX, 2” Barrel. Note slight dent in wood. Expansion .64”

I’ve mentioned factors like kinetic energy and momentum in other columns here, and I’m not convinced that any of them measure anything effective.

How deep a bullet goes does measure effectiveness. How big a hole it punches does matter as well. And of course, as we have discussed, where you hit matters. There are other possible factors involved but we will save those for another day. Today we are not concerned with which caliber you shoot, we are concerned with what you are your actual gun and the rounds you carry in it, and the effect it can have on your life expectancy.

Most people are simply not prepared to go through the hassle of properly preparing a block of 10% ordnance gelatin, as good a material as that is, since it not only requires careful preparation, it also requires you to maintain the temperature of the block at 4 deg. Centigrade (39.2 deg F) with a very narrow margin of error. There are about 2 dozen steps to preparing and calibrating ordnance gel and if any are not followed to the “T” – such as dissolving the powder in cold water not hot – if not then the mixture must be thrown out. When it comes to “calibration” you must fire a .177 caliber BB into the block at 590 feet per second (there is a correction chart if the velocity is off so have that handy). If the penetration is not right then you have to start all over. Then you shoot that expensive block with one round and that is it. Again, if you have the money or the lab, it is a very good material but it takes a lot of care to be valid.

What the average guy needs is a test that we can use conveniently as a sort of “reality” check and quality control standard on the very expensive premium carry ammo he is putting in his gun. To be sure there are several materials we can use but before we start allow me to warn you of something that even the “J-ello junkies” (I don’t mean that term to be critical – I have shot a lot of ordnance gelatin myself) don’t seem to realize. It is NOT what the bullet does to the medium that matters (other than penetrate) but rather it is what the medium does to the bullet.

What we are looking for is comparing the properties of one bullet to another. I can find no good correlation between actual stopping power, killing power, blowing back power, or any effective gunfight power and how well a bullet blows up a block of gelatin. The same is true for other things you read about, like how it stretches the block, or creates stress cracks in the block. I can’t say there isn’t a relation, but nothing has been proven or demonstrated to date that matters one wit. When I was younger folks bought up big blocks of clay to shoot – how disappointed we were when our “magic” bullets did not blow up critters the same way.

As good as gelatin is, it gives a false sense of security when it comes to consistent performance. Harkening back to that load of excellent reputation, the .357 125gr JHP, it will produce (or at least in most brands) about 12-14” of penetration in 10% gel and will expand violently. I have seen that same load penetrate as little as 1” on a human being (a head shot on a hard headed subject) and I have all seen the same load shoot all the way through, because it didn’t hit anything solid. People and critters are not homogenous. One just never knows.

In animals and people I find that general class of load, which penetrates from 12 to 14 inches of 10% gelatin, will typically penetrate on average about 9 to 10 inches if the hit is in the chest cavity. Though it is not extremely rare to see one go 4” deep or again, go completely through. Why the difference? I do not know, other than that there is a lot of stuff in a human of varying consistency and resistance. The point is that we use mediums because they are consistent, not because they will tell us exactly what will happen. They give a rough idea and compare the characteristics of one bullet to another.

Winchester Ranger .45 Auto +P 230gr JHP – Split 2 layers of wood but did not put a hole in it. Expansion .74”

While we cannot cover all the mediums in one article, let us start with one that most folks can obtain and manage with a minimum of fuss and bother. And one that is even accepted by the laboratory guys as a fairly decent substitute – plain old H20 – tap water. It may not be the best but it certainly is available and it is cheap.

The generally accepted standard is that water is about 1.8 times easier to penetrate than gelatin. I won’t argue with that but if it is true then folks may be in more trouble than they imagined, as you will see shortly. There are several ways in which to employ water as a test medium. Some are more involved than others and probably give some good “snap shots” of performance.

The “official” way to use water is to construct a “Fackler Box”, named after the well known researcher and co-founder of the International Wound Ballistics Association (of which I was an early member). It is a simple box designed to hold a column of water held in 1 gallon ziplock bags. You shoot though this stack of bags and measure the deepest penetration. Then divide that distance by 1.8 to obtain penetration in gelatin, which is claimed (with good reason) to replicate penetration in pig muscle.

What I have in mind for my testing is to offer something even simpler (more complex is also possible but we will only touch on simple this time around).

This test is simply to utilize 2 liter soda bottles. In order to do this, fill the bottle to the top and screw on the cap. Lay the bottle on the side with the cap end toward the gun. It would be just as well if you put something behind the bottle to catch the bullet – I use an old welcome mat from Wal-mart that is made of approximately 3/8th inch thick foam rubber, cut into 8” squares. This will normally not expand the bullet any further after penetrating the bottle – IF it penetrates the bottle! – and allows you to examine the end results. I shoot the bottle about 1” above the cap with the bullet path headed for the center of the bottom of the bottle.

It is worth noting that the bottom of a 2 liter bottle is somewhat thicker and harder than the rest of the bottle. If your bullet makes it through this, it is probably a good sign. I like to put a bit of wood behind the bottle, before the rubber matting, to see if it really has any “steam” left to puncture or dislocate a vertebrae. I use 2 layers of wood that are about ¼” thick, each, not much resistance. It is merely an indicator, since the bullets will often bounce off the bottom and end up in the middle of the ruptured jug.

The bottle always ends up the same, decimated. It is the bullet we are concerned with. How far does it go, does it exit, and how much does it have left if it even exits.

Remember, we don’t care what happens to the bottle or the water column. Living flesh, while it contains about 80% water, is not a liquid. Nor is it a gel. It is of various levels of hardness and viscosity and it is connected by cord like stringy fibers. You can just take your finger and poke a hole in gelatin or even scoop out a piece – you cannot do that with flesh at normal speed or pressure.

Shooting cans or jugs of water or fruit and vegetables may be spectacular but the damage to the container tells you nothing about effectiveness that you can rely on.

I should also mention here that there is such a thing as hydraulic force and a “shock cavity,” and it does come to bear sometimes when high velocity rifles are used. I might even believe that it could have some bearing in some rare cases with pistols but it does not seem to be something you can count on. When our life is on the line we don’t depend on things that can happen. Pray for the best but prepare for the worst!

A bullet that hits flesh and blood might also hit bone don’t forget, and it may also encounter heavy clothing and other barriers on its way to the soft target you intend. We can attempt to replicate that, but on this first easy test we will limit the complexity. The water column we are shooting here is only about 8.5” in length. Recall that conversion factor of 1.8 we mentioned earlier. Be prepared for a rude awakening. Some highly rounds that get a lot of chatter, shooting bullets as widely varied as a 110gr JHP from a Magnum or a relatively heavy and slow 230gr JHP from a .45, may not go as deep as you might have thought! Bullets don’t read charts very well.

Take a look at the typical performance of typical rounds we tend to carry in the accompanying pictures. Surprised?

Federal .40 180 Gr. HST, 4.5” barrel. Put a hefty dent in the wood and expansion .70”

Note in this example the Cor-bon DPX load from a snub .38 expanded as large and penetrated almost exactly as deep as the well respected .357 Magnum JHP from a 4” barrel. Whether or not the .357 would have put a bigger hole in the heart and lungs is open to question.

You have the simple test. Remember, it is not some super cool test to calculate how much “stopping power” we have – or don’t have as the case may be. It is meant to give us a clue as to whether the ammo we are shooting lives up to its billing or your expectations. Nor does it take into account expansion after penetrating clothing or chance barriers, which can be important, or hitting a bone upon entry. You can work out some tests which simulate that but we will address it at a later date.

I should point out that in feeling this little project out, one person observed that the penetration of all loads was much less than one may have figured, something I noted myself. It was mentioned that there may be something going on here due to the size and strength of the container, something on the order of a “torpedo bulge” such as used on ships during World War II. I did look this up and admit I am not quite sure exactly how the bulge works, nor am I sure this is the same, since the bottle ruptures very early on in the “ballistic event”. In any case, it probably does not matter much. We are comparing one load to another in this one particular and consistent test which is easily repeatable under a wide range of weather conditions. You can use a milk jug also but don’t mix the two. The Milk jug is shorter and has a softer bottom.

I make no claim that a bullet that won’t penetrate the bottle completely or even damage the little test piece of wood is wholly inadequate for self defense. Personally, it is my “litmus test” since I desire my bullet will strike and damage the upper spine but I am not suggesting it should be yours. Perhaps you will only be interested in how big the bullet expands. With a bullet that misses the CNS that can be a factor. Personally, I would not want a bullet that totally fragmented or lost more than 75% of its weight in water. But I repeat the warning to ignore the damage the hydraulic force does to the bottle – normally you don’t get splashed with blood when you shoot flesh and blood up close with a pistol.

Actually, Hoppy, Gene and Roy and their ilk knew a thing or two about how bullets really work. Now if I could just work on shooting the guns out of the bad guy’s hands?????

Until next time….”Happy Trails”

Jim