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How to Properly Test Bullet Penetrating Power

stopping power

Fun with Ballistic Gel, Building Materials, and Plywood

Sometimes at the gun store we'll see a variety of different styles of ammunition and we'll wonder – how much more effective is one from the other? Are you curious to see how one brand performs against another? We wrote an article previously which you may be interested in: The Caliber Wars are Over

We've enclosed some fun activities that can be done cheaply and reliably to test the effectiveness of different rounds. It's one thing to read about them and it's another thing to see it for yourself.

We're including some testing methods taken directly from the FBI's own ballistic testing protocols.

While it's not necessary to follow the government's standards of rigidity to the letter – these events can demonstrate specifically how a type of round will perform given certain circumstances. We've also included a bonus test for #8 that uses the old U.S. Army rule for 1/2” pine boards for determining whether or not a round will produce a viable casualty. That test was in no way definitively proven, but it can be insightful when dealing with subsonic rounds and distance.


Here's a very good recipe for producing ballistic gel resembling the sort used by the FBI for their testing purposes.

1. Ballistic Wound Effects – Just the Gelatin

This test demonstrates the expansion of a round in flesh. It's also a great indicator of the energy transfer from the bullet to the body into the first 15-30 cm of tissue.

2. Light and Heavy Clothing – Fabric Covered Gelatin

This is really a four part test. All tests are done at 10 feet from muzzle to target.

2a) The first part uses just a basic cotton material. It can be a t-shirt or an old sheet. Recommended thread content is 48 threads per inch. This is meant to simulate an undershirt.

2b) In part B, an old, thicker cotton dress shirt or button-up is about the level of thickness you're going for. Recommended count is somewhere around 80 threads per inch but in total, it's meant to replicate conditions of shooting through a thicker cotton button-up. This is considered “Light Clothing”.

2c) Part C includes a relatively thick 10 ounce down comforter. Thankfully, you can leave the one on your bed alone. This is more of the material and thickness you would expect with your average horse blanket. What you're trying to estimate is a jacket or thicker material you'd expect to see someone wearing.

2d) If you want to jump straight to the head of the class – go ahead and stack all the previous layers. A cotton undershirt, a cotton button-up, and a thick construction or horse blanket. You are now simulating conditions of someone in full cold weather gear.

3. Heavy Clothing at Distance – Fabric Covered Gelatin

This test is arguably an extension of the last one. The same conditions apply as in 2d, i.e. heavy clothing applied to the target to simulate cold weather gear. Instead of taking the shot at 10 ft, though, take the shot at 20 yds. This test gives the shooter an accurate depiction of the penetrating power of a particular round with decreased velocity and a greater range.

4. Car Door Penetration Test – 20 Gauge Steel

For this test, you'll need two pieces of 20 gauge steel – hot rolled and galvanized. These plates should be six inch squares and placed in front of one another in a series. Behind the last plate, at a distance of 18 inches, is where you place your gelatin block. Dress up that gelatin block in Light Clothing as described in Test 2.

In the FBI's estimates, this test demonstrates a bullet's capacity to penetrate through the thickest part of an unarmored car door and cause harm to the passenger.

5. Shooting Through an Interior Wall - Gypsum board

Instead of steel, you're going to get two six inch squares of 1/2” gypsum board for this test. Position the squares so there is a 3 1/2” space between them. And behind that by a distance of 18” is where your ballistic gel block will go in it's Light Clothing. This should be a decent enough estimate for a bullet's capacity to pass through an interior wall and strike a target.

6. Driver's Side Windshield – Automobile Glass

Ideally, for this test you're going to get a 15” x 18” piece of 1/4” A.S.I. laminated automobile safety glass. Placing this piece at roughly a 45º horizontal angle and 15º vertical offset, the gelatin block should be 18 inches behind the estimated trajectory of the bullet after angle of impact. This may take a bit of planning. Make sure the ballistic gel is clothed in Light Clothing as described in Test 2d. With these conditions in place, measure 10 feet from muzzle to glass.

7. Driver's Side Windshield at Distance – Automobile Glass at 20 yards

Same materials as the previous test except you remove the vertical offset so the glass is just tilted at 45º. You'll be backing up to 20 yards and this should simulate a driver coming head-on.

8. U.S. Army Board Test – 1/2” Pine Board

The 58 ft/lb rule as a litmus test for the ability of a bullet to produce a casualty was never concretely established as a standard. However, the US Army had briefly adopted this measurement as its testing ground for both existing and potentially new small arms munitions. As such, it's been determined that the force required by surface area to penetrate a 1/2” pine board would be graciously in excess of this arbitrary measurement.

While it should never be the definitive proof of effectiveness of any bullet – it can provide some interesting insight into a round's effectiveness at distance.

For instance, a .22lr round at 10 feet versus 50 yds should be an interesting comparison of different grains and styles.

These tests are also great to try out with longer range options. At ranges up to 300 yds, you can see the difference in a NATO 5.56 mm round's impact versus 7.62 x 39 mm. Ultimately, the choice is yours in terms of altering any of the conditions of these events. They are mostly here, in this format, to provide you with some entertainment and practical research guidelines.

James England

About The Author

James England is a former United States Marine Signals Intelligence Operator and defense contractor with over two tours spread over the Al Anbar province and two more operating across Helmand and Baghdis. He is presently a writer focused on Western foreign policy and maintains an avid interest in firearms. A graduate of the University of North Carolina at Wilmington, he presently resides in New Hampshire – the “Live Free or Die” state. He is finishing up his first novel, “American Hubris”, which is set to hit shelves in Fall of 2015.