Monday, December 30, 2013

Ruger 10/22 Magazine Accessories from TANDEMKROSS


One nice thing about owning a Ruger 10/22 Rifle is the sheer volume of aftermarket parts and accessories available.  Some folks will leave their 10/22 in "box stock" condition and enjoy it for decades.  Others will turn their 10/22 into the proverbial money pit and swap out parts until all that remains is the serial numbered receiver.  I've lived in both worlds over the years so I've had the chance to work on a few 10/22 project rifles.  The one common component that all the rifles shared was the Ruger 10/22 factory 10 round magazine.

TANDEMKROSS has developed two add-on products for Ruger 10/22 magazines that offer a reasonably priced upgrade for Ruger factory magazines.  These products do not alter the factory magazines in any way.  The TANDEMKROSS Magazine Bumper and Magazine Doubler can both be purchased directly from TANDEMKROSS through their webstore.  I recently had the chance to install and use both products.


Magazine Doubler installation was very simple and required only my magazines and a screwdriver.








The Magazine Doubler locks into the bases of the 10/22 magazines and is secured with a butterfly clamp that nests in the thumb depression on the magazine.









Installation of the Magazine Bumper is similar to the Magazine Doubler except a single-sided clamp is used to secure the bumper base to the single magazine.



With the installation finished, the Magazine Bumper adds just over 1/2" to the magazine height.  The bumper base also includes grooves that allow you to yank down on the magazine in case of a partial feed that prevents the magazine from dropping free.







With retail prices of $8.99 for the Bumper and $9.99 for the Doubler, these kits offer a significant enhancement at a modest price.  I will be adding these kits to all my competition magazines prior to my next competition shoot.


I shot a range video demonstrating the Bumper and Doubler in action, but the wind was up and I had to delete most of the original audio and do a voice over.  I hated to do it, but I couldn't scrub the wind from the original audio.  The point of the video was to show that the kits offer enhancement to factory magazines without impacting reliability.



Tuesday, December 24, 2013

Corbon 45 Auto +P 230 Grain JHP Denim and Clear Gel Tests

I've tested several Corbon loads over the last two years with generally mixed results.  Corbon is known for their and premium priced defense loads that tend to run on the fast side in comparison to other manufacturers.  This was my first opportunity to test their classic JHP load in 45 Auto.  Having recently tested their similar 9mm +P 125 grain JHP load with great results, I was anxious to see how their 45 Auto load would perform.

Test Pistols:

Test Protocol:
Step 1)  Measure and record temperature and relative humidity.
Step 2)  Run a 5 shot velocity average over a ProChrono Digital Chronograph at a distance of 10 feet.
Step 3)  Run first bare gel test shot into a block of Clear Ballistics Gel that is calibrated to 10% Ordnance Gel density.  Shot distance is 10 feet.
Step 4)  Run second test shot through 4 layers of 14 oz/yard heavy-weight denim.  Shot distance is 10 feet.
Step 5)  Repeat steps 3 to 4 with alternate barrel length.
Step 6)  Run a 600 fps calibration test bb shot into the Clear Ballistics gel block and record penetration depth.

Test Results:

Video Documentation of the Entire Test from Range to Bullet Recovery:

My Thoughts on This Load:
The one positive performance characteristic was that the load met the manufacturers published velocity specification when fired from a similar length test barrel.  I was really surprised to see the bullets repeatedly fail to expand in my test.  I was hoping for performance similar to the 125 grain 9mm +P load from this same ammunition line.  The additional problem with core-jacket separation was another unexpected result.

Pick or Pan:
Based on this test series of 4 shots taken from a single box, I would pan this one for failing to expand and for core-jacket separation when it did expand.  These undesirable traits are unacceptable from a premium priced defensive load.




Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested.  All tests represent actual performance in ballistics testing media.  Terminal performance in all other media will show different results.  It is up to each individual to make their own personal decision on which specific ammunition to use for their needs.  It's also critically important to test any ammo in YOUR SPECIFIC FIREARM before relying on it for any purpose.

Ammunition labeled as +P or +P+ should only be used in firearms that have been certified by the manufacturer as safe for the additional pressures generated by these ammunition types.

Thursday, December 19, 2013

Winchester Ranger T-Series 357 Sig 125 Grain Denim and Clear Gel Test

Over the last two years, I've really come to appreciate the 357 Sig cartridge.  From my limited testing, it has consistently performed through the heavy clothing barriers that cause other calibers to experience expansion failure.  If I had to guess why it performs so well, I would guess that the added speed this cartridge generates helps expansion.

The Winchester Ranger series of ammunition is Winchester's Law Enforcement ammunition line.  The T-Series bullets are a modern version of the old Black Talon ammunition line that was vilified in the press and subsequently removed from the market many years ago.  I was really looking forward to testing this the Winchester Ranger T-Series because so many people on various forums speak so highly of it, and this load has "street cred".   I expected it to be a great terminal performer based on how stringently Winchester tests this line of ammunition.


Test Pistols:

Test Protocol:
Step 1)  Measure and record temperature and relative humidity.
Step 2)  Run a 5 shot velocity average over a ProChrono Digital Chronograph at a distance of 10 feet.
Step 3)  Run first test shot through 4 layers of 14 oz/yard heavy-weight denim.  Shot distance is 10 feet.
Step 5)  Run a 600 fps calibration test bb shot into the Clear Ballistics gel block and record penetration depth.
Step 6)  Repeat steps 1 to 4 with each barrel length.  

Test Results:


Video Documentation of the Entire Test from Range to Bullet Recovery:

My Thoughts on This Load:
Over the last few test reports, I've been hinting that the number of expansion failures was increasing since switching over to 4 layers of 14 oz denim material.  I really didn't expect that this load would fall into the expansion failure category.

You may be looking to me for a reason why the bullets failed to expand.  I can only offer the following picture showing all three recovered bullets with their hollow point cavities completely plugged with denim.  They are arranged in the order they were shot with the 4.5" barrel test shot on the left and the 3.4" barrel test shot on the right.  The 4" barrel test shot is in the middle.  You may notice that the petals were trying to separate on the left-most bullet, but performance was virtually identical with all three recovered bullets.

The one bullet that did expand, when shot into bare gel, experienced significant fragmentation.  I believe this test shot may be the lowest recovered weight percent of any of my previous tests.  The Ranger T-Series bullets are not bonded so some fragmentation is expected as the jacket peels back from the lead core.  I was really surprised by how much of the lead core was dropped in the wound channel.

Pick or Pan:
Plugging with denim and failing to expand across barrel lengths ranging from 3.4 to 4.5 inches pushes this load into the pan category.  With the plugged bullets having the potential to penetrate to 30 inches or more, that's just not something I'm comfortable with.







Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested.  All tests represent actual performance in ballistics testing media.  Terminal performance in all other media will show different results.  It is up to each individual to make their own personal decision on which specific ammunition to use for their needs.  It's also critically important to test any ammo in YOUR SPECIFIC FIREARM before relying on it for any purpose.

Ammunition labeled as +P or +P+ should only be used in firearms that have been certified by the manufacturer as safe for the additional pressures generated by these ammunition types.

Friday, December 13, 2013

Hornady Custom 45 Auto 200 Grain XTP Denim and Clear Gel Test


Before the innovation of Critical Defense and Critical Duty, the Hornady Custom line of ammunition was the premier defensive ammunition line from Hornady.  Loaded with their famous XTP bullet, the Hornady Custom line was know for accuracy, moderate velocity, modest expansion, and deep penetration.  I was really interested in finding out if this lighter 45 Auto bullet, loaded to standard pressures, would expand reliably from a shorter concealed carry length barrel. 

Test Pistols:

Test Protocol:
Step 1)  Measure and record temperature and relative humidity.
Step 2)  Run a 5 shot velocity average over a ProChrono Digital Chronograph at a distance of 10 feet.
Step 3)  Run first bare gel test shot into a block of Clear Ballistics Gel that is calibrated to 10% Ordnance Gel density.  Shot distance is 10 feet.
Step 4)  Run second test shot through 4 layers of 14 oz/yard heavy-weight denim.  Shot distance is 10 feet.
Step 5)  Run a second bare gel test shot with longer test barrel.
Step 6)  Run a 600 fps calibration test bb shot into the Clear Ballistics gel block and record penetration depth.

Test Results:

Video Documentation of the Entire Test from Range to Bullet Recovery:

My Thoughts on This Load:
It's difficult to get excited about writing up a test when the ammunition fails to expand during the denim test.  The unfortunate thing is that this is the first of many expansion failures that I'll be working through over the next few weeks.  As I've stated before, the 4 layers of heavy denim test a tough test to pass.  You can see the recovered bullet was on the verge of expansion, but just didn't have enough of the test media inside the hollow point cavity to initiate full expansion.      

I was really surprised to see the evidence of yawing or tumbling left by the denim shot in the gel block.  The more I think about yawing, the more sense it makes.  If the nose of the bullet wasn't facing forward, the gel media couldn't be forced down into the hollow point cavity to trigger expansion.  When I recovered the denim test shot, the hollow point cavity was empty so the denim must have been dragged out of the cavity during the unstable yawing path down the gel block.  That may also explain why the bullet stabilized and assumed a nose forward profile at the end of travel.

The two bare gel shots performed exactly as you would expect an XTP to perform.  We saw some light fragmentation, modest expansion, and deep penetration. 

Pick or Pan:
For a short barrel 45, this load wouldn't be my first choice.  The Hornady Custom line also includes a +P version of this load with a published velocity of 1055 feet per second.  The extra 155 feet per second velocity may end up being the better choice for a reliably expanding load in a short barrel 45.  The Critical Defense 185 grain load has been optimized for short barrel pistols, so that may also be a better choice.








Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested.  All tests represent actual performance in ballistics testing media.  Terminal performance in all other media will show different results.  It is up to each individual to make their own personal decision on which specific ammunition to use for their needs.  It's also critically important to test any ammo in YOUR SPECIFIC FIREARM before relying on it for any purpose.

Ammunition labeled as +P or +P+ should only be used in firearms that have been certified by the manufacturer as safe for the additional pressures generated by these ammunition types.

Saturday, December 7, 2013

Make a Duck Tape Holster - How To

If you live in the US, then you must have at least heard of Duck Tape.  Duck tape is a specific brand of duct tape manufactured by the Shurtech company.  Shurtech took a tool box staple and made it cool by adding new colors, patterns, and different tape formats.  I've used the Duck Tape sheets and rolls over the years and always wanted to try my hand a making a Duck Tape wallet.  Wallet turned into pocket holster one day last week so with the snow keeping me off the range this weekend, I thought I would try my hand at holster making. 

Just so you know, this was a one shot deal.  I have a tiny bit of holster making experience with kydex, but you can count the number of holsters I've made on one hand.  What I'm trying to say is this was ridiculously easy to do so if you have some spare time, have at it.  I'm fairly certain you'll end up with a holster when you are done.

My first decision was what kind of holster I wanted to make.  That was pretty easy.  The Taurus M380 revolver is smaller than a J frame or Model 85.  Holsters made for either of those will end up being large.  They work, but why not get the holster as small as possible.

First stop was the flat bed scanner to create the pattern for the holster.  


I love this digital camo Duck Tape pattern.  The minute I saw it, I bought a roll and a couple of sheets.  I wasn't really sure at the time how I would end up using the tape, but it seemed perfect for this holster project.  The pistol picture is what I got after scanning the pistol.

Using the scanned image (make sure it prints life size) of the pistol, I used a clear ruler and black Sharpie to create my holster template.  I started with the line where I wanted the holster mouth to end up on the pistol, then traced the primary outline of the pistol using a quarter inch of extra space to account for the width of the pistol.  In hindsight, a half inch would have been better but this worked.

After cutting out your pattern, it's back to the scanner to make a copy of your pattern.

Using a glue stick, I positioned both pattern halves on a sheet of thin poster board.  I'm sure you could use a plain sheet of paper as the inner most layer of your holster, but I had this poster board handy and it worked out well.  It ended up giving the holster just the right amount of "body" and keeps it from collapsing in your pocket when you draw your pistol.  

With the holster core complete, it was time to start laying on the Duck Tape.  I had some sheets of aqua blue on hand so I started the holster with a layer of blue, then digital camo.  The holster body displayed below was now 1 layer of poster board, 2 layers of aqua blue, and two layers of digital camo.   

With the shell complete, it was time to do a test fit and bend the holster to the shape of the pistol.  I used half width strips from the Duck Tape roll to join the holster edges.  This was the really tedious part when I was learning as I went.  Just take your time and don't try to be too perfect fitting flat tape to curved surfaces.  I added one more sheet of tape to the outside of the holster after joining the edges.  It added a bit more body and covered up most of the ugly edges.

I was really pleased with the way the holster turned out.  The pistol draws easily and the holster stays in my pocket.  I went with an open muzzle design, but made sure to allow for plenty of extra holster length.  I don't want the muzzle in direct contact with the bottom of my pocket.

The finished holster tips the scales at 1.015 ounces and I'm really happy with the way it turned out.  It sits fine in the pocket, but I'll wear if for a few days and make sure it doesn't tip in my pocket with extended wear.  I have no idea how long it will last, but for now I think it looks great and ended up being exactly the holster I was looking for.

As with all holster projects, it's your responsibility to assure the trigger is covered with material sufficiently stiff enough to protect against trigger activation while in your pocket.

Friday, December 6, 2013

Lehigh Defense 45 ACP 174 Grain Maximum Expansion Denim and Gel Tests


Over the last 18 months, the folks at Lehigh Defense have sent me several boxes of their ammunition for testing.  The most recent samples included a box of their 174 grain Maximum Expansion 45 ACP loading.  I tested this load previously in two short barrel pistols so this time around I tried both short barrel and long barrel tests.  I really appreciate the folks at Lehigh Defense for proving the testing samples.

Lehigh Defense manufactures several lines of projectiles and ammunition for competition, hunting, and personal defense.  They machine their bullets from solid copper or brass with special purpose designs.  Some bullets are designed to fragment, others excel at penetration, and the tested load is designed for maximum expansion.  Lehigh Defense ammunition is premium priced and I've always found their quality to be exceptionally good.

Test Pistols:


Test Protocol:
Step 1)  Measure and record temperature and relative humidity.
Step 2)  Run a 5 shot velocity average over a ProChrono Digital Chronograph at a distance of 10 feet.
Step 3)  Run first test shot through 4 layers of 14 oz/yard heavy-weight denim and into a block of Clear Ballistics Gel that is calibrated to 10% Ordnance Gel density.  Shot distance is 10 feet.
Step 4)  Run second optional bare gel test shot into a block of Clear Ballistics Gel that is calibrated to 10% Ordnance Gel density.  Shot distance is 10 feet.
Step 5)  Run a 600 fps calibration test bb shot into the Clear Ballistics gel block and record penetration depth.

Test Results:

Video Documentation of the Entire Test from Range to Bullet Recovery:

Short Barrel Test

Longer Barrel Test

My Thoughts on This Load:
This load performed perfectly in all three test shots.  It opened completely and expanded fully.  I included the picture below so you can see how Lehigh machines the bullets so they expand to the largest possible diameter without the petals over-expanding and wrapping back to the bullet shank.

In the picture below, I've arranged all three recovered bullets.  The bullet at the top center was fired from the shorter barrel and 981 feet per second wasn't quite enough velocity to allow the bullet petals to expand to their maximum.  Both shots from the 1911 achieved their maximum expansion with their petals resting nearly perpendicular to the bullet shank.  In the Clear Ballistics terminal test media, 1000+ feet per second appears to be the velocity threshold for this bullet to achieve optimal expansion.  I decided to include the quarter from the Great State of Arkansas so you can see how huge the recovered bullets really are.  If Arkansas had a half dollar coin (1.205" diameter), it would still be smaller than these recovered bullets.

Pick or Pan:
If you are looking for a load that delivers maximum expansion, this is your high water mark.  I've never tested anything else that expands, and maintains expanded diameter, like a Lehigh Defense Maximum Expansion bullet.  Penetration pundits will dismiss this load since it fails to achieve 12 inches of penetration.  That's OK.  Love this load for achieving what it was purpose built to do.  Don't punish it for falling short in other performance areas it was not designed to meet.



Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested.  All tests represent actual performance in ballistics testing media.  Terminal performance in all other media will show different results.  It is up to each individual to make their own personal decision on which specific ammunition to use for their needs.  It's also critically important to test any ammo in YOUR SPECIFIC FIREARM before relying on it for any purpose.

Ammunition labeled as +P or +P+ should only be used in firearms that have been certified by the manufacturer as safe for the additional pressures generated by these ammunition types.

Tuesday, December 3, 2013

Federal Premium 9mm Luger 124 Grain Tactical Bonded Denim and Clear Gel Test



Many thanks to blog reader Fred for supplying the ammunition for this test.  He's sent in several different loads for testing this year and I really appreciate it.

The Federal Premium Law Enforcement Ammunition Tactical Bonded 9mm Luger 124 Grain Tactical HP may hold the record for the longest name assigned to anything I've previously tested.  While the HST may be the current darling of the Federal line, the Tactical Bonded covers the requirement for a bonded bullet that will hold together when fired through intermediate barriers.  I was very interested in seeing how this standard pressure bonded load would compare with other Hydra-Shok and HST standard pressure 124 grain loads.  As it turns out, it did really well. 

Test Pistol:

Test Protocol:
Step 1)  Measure and record temperature and relative humidity.
Step 2)  Run a 5 shot velocity average over a ProChrono Digital Chronograph at a distance of 10 feet.
Step 3)  Run first bare gel test shot into a block of Clear Ballistics Gel that is calibrated to 10% Ordnance Gel density.  Shot distance is 10 feet.
Step 4)  Run second test shot through 4 layers of 14 oz/yard heavy-weight denim.  Shot distance is 10 feet.
Step 5)  Run third test shot through 4 layers of 14 oz/yard heavy-weight denim.  Shot distance is 10 feet.
Step 6)  Run a 600 fps calibration test bb shot into the Clear Ballistics gel block and record penetration depth.

Test Results:

Video Documentation of the Entire Test from Range to Bullet Recovery:

My Thoughts on This Load:
This was my first experience testing any of the Federal Tactical Bonded ammunition line.  For a mid-weight standard pressure loading, it did exceptionally well with expansion, weight retention, and penetration.  Published velocity for this load is 1160 fps from a 4" barrel.  Our 3.4" barrel generated 1100 fps, which is right on target for the reduced barrel length.

In hind-sight, I really wish I had tested this in an 18" gel block instead of the 16" block I had on hand for testing.  Fortunately, we were able to recover the bullets and use them to model the penetration depth of the denim shots.

If this load has a downside, it's limited availability.  The Tactical Bonded ammunition line is marketed primarily to Law Enforcement.  You won't find it at the typical retailers that carry ammunition.  I've seen small quantities pop up on the websites of internet ammunition retailers from time to time so that's probably going to be your best chance of locating the ammunition.

Now I'm dying to test the Tactical Bonded 357 Sig load, if I can ever track down a box.  



Pick or Pan:
All test shots performed exactly as expected with no surprises.  This load is definitely a pick, and performed exceptionally well for a standard pressure loading fired from a short barrel test pistol.



Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested.  All tests represent actual performance in ballistics testing media.  Terminal performance in all other media will show different results.  It is up to each individual to make their own personal decision on which specific ammunition to use for their needs.  It's also critically important to test any ammo in YOUR SPECIFIC FIREARM before relying on it for any purpose.

Ammunition labeled as +P or +P+ should only be used in firearms that have been certified by the manufacturer as safe for the additional pressures generated by these ammunition types.

Friday, November 29, 2013

The Continuing Evolution of Terminal Ballistics Testing - A Guest Blog by Charles Schwartz

I've been fascinated by terminal ballistics testing since the early 1990's when I first started reloading.  Back then, we received new phone books each year and I was "that guy" who would sweep through the neighborhood asking for the old phone books so they could be "recycled".  By recycled, I really meant they would be soaked in my bathtub and subsequently shot at the range.  Over several years, I caught many bullets in those hydrated phone books, developed some awesome handloads, and learned that not all bullets were created equal.  I really enjoyed the load development and testing, but eventually had to stop due to other life priorities.

Fast forward to 2009.  The pocket pistol boom is in full swing and I catch the bug.  I start looking for terminal performance data for these short barrel pistols and find very little information is available.  I quickly came to the realization that if I wanted terminal performance information, I'd better start tracking down phone books again.  Since 2009, I've progressed from phone books, to water jugs, a failed attempt to create an aqueous media bullet trap, SIM-TEST, and finally Clear Ballistics Gel.  About two years ago, I started sharing my test results on the blog.  Some of the early tests are embarrassing to view now, but I've done my best to constantly improve the quality of the data I capture, and implement the suggestions from readers viewing the tests.  One of those suggestions was to cross validate my terminal performance results with the Soft Tissue Ballistic Penetration Model found in Charles Schwartz's book titled Quantitative Ammunition Selection.

When I transitioned from SIM-TEST media to the Clear Ballistics Gel last year, skepticism ran high that this virtually clear, temperature insensitive, reusable gel could really be a suitable substitute for 10% Ordnance Gel.  Fans of the Schwartz book would frequently check my test results vs. the Soft Tissue Ballistic Penetration Model and let me know that the results in line with the model.  This was a confidence booster for me and I always thought I should locate a copy of the book to see what this model was all about.  Last month, I received an iPad for my birthday so I downloaded the Kindle reader app and purchased the Quantitative Ammunition Selection book from Amazon.  As I was puzzling through how to integrate the model into my data sheet, I received an unexpected email from Charles Schwartz.  (long story how this unexpected contact happened not suitable to cover now) We’ve been working together over the last two weeks and he’s agreed to explain a bit more about the models in his Quantitative Ammunition Selection book and also the specific metrics I will be adding to my data sheet going forward.  With that, take it away Charles!


Since I’ve long been a fan of Bruce’s work, especially as it relates to his ammunition tests conducted in the Clear Ballistics Gel test medium, I could not help but feel more than a little honored when he asked me to write a guest article for his blog.

     And why not?

I am tremendously impressed by the range of his work and the considerable database of Clear Gel tests that he has amassed. I believe that Bruce’s work stands as strong indication that eventually synthetic test mediums such as Clear Gel will offer the promise of conducting valid, scientifically-repeatable terminal ballistic tests without the attendant annoyance and expense associated with testing in calibrated ten percent ordnance gelatin. Imperfect as it is at this early time, I believe that Clear Gel, and the general class of synthetic soft tissue surrogates known as PAGs (physically associating gels), has great potential in the field of terminal ballistic testing once the material technology matures. Once the material properties of PAGs are improved through R&D to the point that they are able to more accurately represent the formation and cyclic duration of the temporary cavities produced by both high- and low-velocity projectiles, I suspect that PAGs will become more widely accepted and rapidly supplant calibrated ordnance gelatin as the soft tissue simulant of choice due to its superior transparency and insensitivity to ambient temperature.

     So, what’s the common interest here?

Well, that’s easy enough to answer. Bruce and I have both gone about pursuing it in different ways, but our ultimate goal is the same. We both want to see the process of terminal ballistic testing made easier and more affordable for the “average guy” without sacrificing validity in the process. Accessibility and accuracy; that’s the goal. Seeing the need for a new process, or a means of updating an old process, is exactly what each of us, in our own way, has been striving to achieve. This, of course, brings me to the discussion of the way that I addressed what I saw as a need for an approachable mathematical model that eliminates the guesswork necessary (until now) when using water as a terminal ballistic test medium.

Water, just like Clear Gel, is an isotropic substance (that is, it is “the same” in all directions) that is insensitive to ambient temperature and has the added benefit of requiring no calibration in order to produce valid test results. So long as the water has not frozen solid or come to a boil, it will produce nearly identical forces to those that arise in calibrated ten percent ordnance gelatin upon bullet impact. Those forces, related to the speed of sound within the test medium and the density of the test medium, are what determines how the bullet and test medium will interact with one another and the more similar they are, the better their respective behavior will correspond to one another. For the sake of comparison, the speed of sound in water at room temperature is approximately 4,910 feet per second, which corresponds closely to that of the speed of sound in calibrated ordnance gelatin at 4,901 feet per second. The densities of both water and calibrated ten percent ordnance gelatin are also very close to one another at 0.999972 gram per cubic centimeter for water at room temperature and 1.040 gram (± 0.200 gram) per cubic centimeter for ordnance gelatin at 39.2° Fahrenheit.

While water produces expansion rates and bullet weight retention nearly identical to that of calibrated ten percent ordnance gelatin, the one drawback with testing in water is that it does not allow for the proper representation of a bullet’s maximum penetration depth as it occurs in other soft tissue simulants without the use of a penetration depth “conversion factor”. Many of these “conversion factors” exist. Ranging in magnitude from 1.8 to 3.0, these factors see common use, and occasionally, bitter debate, in the self-defense and firearms enthusiast communities. However, the problem inherent with the use of these factors is that no correlative study exists that confirms the validity of any of these values.

Of course, such modeling has been attempted before and more than once, but the problems with these prior attempts are manifold. Some attempts at modeling terminal ballistic performance are simply too subjective or are poorly defined. That is, they are composed of otherwise meaningful physical variables that have been cobbled together, often haphazardly, in the hope that some significant perspective or interpretation might be gained from them. Other models, while capable of producing highly correlated, objective, dimensional results, are simply too esoteric for the average firearms enthusiast’s or concealed weapons carrier’s use because they either rely upon advanced mathematics far beyond the reach of the “average guy” or because they are presented in such a manner as to make them unreachable for all but a few.

     Fortunately, it doesn't have to be this way.

The solution to this issue is to produce a mathematical model of high correlation that accurately predicts penetration in soft tissue simulants like calibrated ten percent ordnance gelatin using water as the test medium while still remaining accessible to the "average guy". Of course, that is easier said than done, but that is where Quantitative Ammunition Selection comes to the fore. The mathematical model found in Quantitative Ammunition Selection relies upon a governing expression; a proportionality of high correlation to a population of 735 calibrated ordnance gelatin test data obtained from no less than ten independent, published, and unpublished sources composed of various ammunition manufacturers, laboratories, and law-enforcement agencies. The QAS model, a predictive instrument, which has a correlation of r = 0.942 when compared against those 735 data, possesses a margin of error of ± 1.00 centimeter at a 95% confidence margin when using water as a terminal ballistic test medium. The QAS model’s yields are expressed in units of length (in centimeters or inches) for maximum terminal penetration and mass (in grams or ounces) for permanent wound mass equivalent as these effects would occur calibrated ten percent ordnance gelatin where ordnance gelatin (or soft tissue) is penetrated and permanently crushed through direct contact with the bullet. Using the QAS model, it then becomes possible to make an “apples to apples” comparison of maximum penetration depth and permanent wound mass in tangible units of length and mass between different calibers, bullet weights, and designs; it’s something that only one other model offers, but that one in particular is hardly accessible to the “average guy”.

Of course, there is a procedure for conducting terminal ballistic tests in water. Many people make the unknowing, but completely understandable, mistake of using plastic jugs and containers of all sorts without considering the confounding factors that they are introducing into the process. After all, how else does one confine water so that a bullet can fired into it?

The problem with such a practice is that plastic jugs and containers come in all shapes and sizes and, more to the point, are made of all sorts of different materials having different thicknesses and physical properties. Plastic jugs, often used in such testing, are made from various polymers such as polypropylene (PP), low-density and high-density polyethylene (LDPE and HDPE), polyethylene terephthalate (PET), and polyvinyl chloride (PVC) to name just a few of the materials in common use today. Moreover, plastic jugs often have variable wall thicknesses in their design that vary significantly in strength depending upon their construction and the material from which they are made. These material properties can, and do, influence the expansion rate and weight retention of bullets passing through them, which in turn, can lead to an inaccurate and misleading representation of a bullet’s terminal ballistic performance.



Instead, the best approach is to use a container with the least dimensional variance in its construction and the lowest material strength available. That ‘ideal container’ is the cheapest generic re-sealable one-gallon freezer storage bag that you can find, with “cheaper” being “better” as a general rule.

     So, why is “cheaper” better?

Well, because any manufacturer seeks to reduce production costs first through the reduction of material used to manufacture a product, the cheapest re-sealable one-gallon freezer storage bags tend to offer the thinnest, most consistent, container wall possible made of the relatively weak polymer, low-density polyethylene (LDPE). It is a material, so fragile and so thin that you can, with very little effort, push your finger right through it. Try that with a two-liter soda bottle made of PP or PET or a one-gallon milk jug made of HDPE and the effects of these different materials becomes quite apparent. Because re-sealable one-gallon freezer bags are the same thickness throughout their construction (except at the point of closure which is no big deal), they also offer the most consistent test results regardless of where bullet impact occurs, another point solidly in their favor.

Once a bullet being tested has been fired and recovered from the water-filled one-gallon freezer bags, it is necessary to record the data obtained for use in the QAS mathematical model. Velocity at impact, average expanded diameter, and retained weight are entered into the QAS model and the maximum penetration depth in calibrated ten percent ordnance gelatin is predicted. After that, the predicted maximum penetration depth is then used to determine the mass of the permanently damaged soft tissue present within the permanent wound cavity and the exit velocity of the projectile from any thickness of test medium, if that is desired. Because Clear Gel possesses physical properties that are extremely close to those of calibrated ordnance gelatin, the QAS model can also be reasonably assumed to predict terminal ballistic behavior in Clear Gel ballistic test medium.

To illustrate this point, one needs to look only as far as Bruce’s most recent test of the Federal 9mm ‘Tactical Bonded’ 124 gr. JHP (LE9T1) in the Clear Gel test medium.

In the first part of that test, a single Federal 9mm 124 gr. ‘Tactical Bonded’ JHP was fired into a bare block of Clear Gel ballistic test medium. The 9mm JHP struck the test block at a velocity of 1,110 feet per second, expanded to an average diameter of 0.5955 inch, retained over 97% of its initial weight, and penetrated to a depth of 11.625 inches before coming to rest in the Clear Gel test block. Comparing the data produced by this test to the predictions made by the QAS model indicates that the QAS model’s prediction is in strong agreement with this particular test result, predicting a maximum penetration depth for this test of 11.478 inches in the Clear Gel test medium.

In the second part of that test, two shots fired through the IWBA four-layer heavy denim barrier, exited the end of the 16-inch long Clear Gel test block so a concrete value doesn’t exit for those tests. Fortunately, it is possible to predict their respective penetration depths and permanent wound cavity masses using the QAS model, thereby “saving” the tests. In this case, the first test bullet struck the test block at a velocity of 1,095 feet per second after passing through the IWBA denim test barrier. It expanded to an average diameter of 0.494 inch, retaining all of its weight before exiting the end of the test block. Entering the available data into the QAS model, the model predicts that the test bullet would have continued for another 1.293 inches before coming to rest at a maximum penetration depth of 17.293 inches. The second test bullet struck the IWBA denim test barrier and entered the test block at a velocity of 1,116 feet per second, expanded to an average diameter of 0.4865 inch, and retained 99.9% of its original weight before leaving the end of the test block. Using the available data, the QAS model predicts that the test bullet would have continued for another 1.981 inches before coming to rest at a depth of 17.981 inches.

The QAS model is also capable of predicting the residual velocity (or exit velocity) of the two test bullets as they left the 16-inch long Clear Gel test block. The QAS model predicts that the first test bullet fired through the IWBA denim barrier would have had an exit velocity of 122.068 feet per second and a residual kinetic energy of 4.125 foot-pounds meaning that it would likely not pose a significant physical threat to a bystander located immediately downrange. The QAS model predicts that the second test bullet fired through the IWBA denim barrier would have had an exit velocity of 152.984 feet per second and a residual kinetic energy of 6.438 foot-pounds meaning that it also would likely not pose a significant physical threat to a bystander immediately downrange. Both test bullets expended approximately 86% – 88% of their available kinetic energy within the target rendering them unlikely to produce a lethal down-range threat and, in the process, demonstrating the advantage of using a JHP (when they expand, that is) for self-defensive use.

As illustrated above, one of the benefits of using the QAS model is that it can be used to confirm a test result or, in the case of a test bullet exiting the test medium unexpectedly, to “save” the test by using the available data (impact velocity, retained mass, average expanded diameter) to predict the terminal performance of the otherwise “compromised” test event. Since I wish to substantiate this opinion further than I have in this article, I am extremely interested in conducting a detailed statistical analysis of Clear Ballistics Gel test data in order to determine just how closely the QAS bullet penetration model correlates to actual terminal ballistic behavior in that test medium. I hope to share the results of that analysis later.

Quantitative Ammunition Selection is available domestically and internationally in hardcover, paperback, and eBook formats and may be purchased at www.quantitativeammunitionselection.com . Just select the appropriate link found on the lower third of the ‘Home’ page for the format that you want.

-Charles Schwartz

Thanks very much Charles for taking the time to explain the background of the new metrics I will be adding on all future test reports.  I think it's important that readers fully understand the science behind the new metrics and what they represent.  Additionally, I'm looking forward to sharing my past and future test results with you so together we can continue to improve the quality of information generated by my testing, as well as others who wish to undertake their own terminal ballistics testing.