Sunday, January 31, 2016

Effectiveness of Old Firearms - III

In our last post, we looked at a study done in Graz, Austria, that compared mass-produced soldier weapons from the 16th, 17th and 18th centuries against modern weapons used by soldiers today. In the last post, we studied the velocities of the various firearms. Today, we will study how the various weapons fared in penetration and accuracy tests.

For the penetration tests, the testers used different types of targets: gel blocks, wooden boards, modern steel plates and 16th century armor plates. Gel blocks are one of the modern ways to evaluate penetration, since it approximates muscle tissue. If the gel blocks are prepared carefully, they can be produced repeatedly with the same consistency, thereby providing for more reliable comparative tests with multiple firearms.

Results of Penetration Tests. Click on the image to enlarge.

As before, a few notes on the results:

  1. The modern weapons are highlighted with yellow background at the bottom of the image.
  2. The flintlock barrel that was used as a pressure tester, was not fired at targets for this series of tests, therefore it shows up in the chart with green background and the words "no applicable data".
  3. The targets were placed at distances of 30 meters (100 feet) and 100 meters (330 feet) and the penetration was measured in millimeters (mm.). In keeping with the spirit of the original tests, your humble editor has not converted these into imperial measurements, but can be easily done as follows: To convert meters into feet, multiply the numbers by 3.3. To convert mm. into inches, multiply the numbers by 0.039. To convert cm. to inches, multiply the numbers by 0.39
  4. The targets were made of steel and wood. For the wooden targets, they were made using wood from spruce trees.
  5. The theoretical maximum range of the weapons was determined by firing each weapon at 60 degree angle. 
As the chart shows, the pistols, whether modern or ancient, all have similar penetrative properties at 30 meter range. Although the modern Glock had the best penetration on both steel and wooden targets, it didn't outperform the ancient pistols by that much in the penetration tests. On the other hand, it has a much longer range than the other pistols (and even the ancient muskets). This is because the tapering bullet does not lose velocity as quickly as a spherical ball does. 

On the other hand, the modern rifles simply outperformed the ancient muskets by a large margin in the penetrative tests, as well as the maximum range test. The AUG firing the NATO 5.56x45 cartridge penetrated about 2x to 3x the depth of the ancient muskets and the FAL firing the NATO 7.62x51 cartridge penetrated about 3x to 5x the depth of the ancient muskets. The maximum range of the modern rifles also far outperformed the ancient muskets.

However, there are other interesting results that became apparent by this series of tests.

Since the ancient weapons all fire larger spherical balls, (the calibers are listed in our previous post) they left larger volumes of wound cavities at shorter ranges. This is because, at close distances, the spherical balls were moving fast enough to do some serious damage. For instance, the flintlock musket that was made in Suhl in 1686, fires a 17.8 mm. diameter ball weighing 30.93 grams and at 9 meter distance (about 30 feet), it left a cavity of 530 cm3. Similarly, the flintlock musket from Austria that was made in the second half of the 18th century, fires a 16.4 mm. diameter ball weighing 26.73 grams and left a cavity of approximately 369 cm3 at a distance of 9 meters.

By contrast, modern weapons fire much smaller tapered bullets, which generally do less damage. At the same 9 meter distance, a modern Steyr AUG rifle firing a 5.56x45 mm. cartridge only left a cavity of 101 cm3.

On the other hand, as the distance increased, the tests showed that the wound cavity made by spherical balls decreased much more significantly. The same musket that made a 369 cm3 cavity at a distance of 9 meters, made a 155 cm3 cavity at 100 meters distance. In contrast to this, the Steyr AUG rifle which made a a cavity of 101 cm3 at 9 meters range, left a cavity of 70 cm3 at 100 meter range. This means that the modern rifle only lost approximately 30% of its penetrative powers at this distance, whereas the older weapon lost about 60%. Still, the older weapon left a much larger cavity, even at 100 meters distance. This explains the extremely horrific wounds experienced by soldiers in the 16th to 18th centuries.

Additionally, the tests showed that the shapes of the wound cavities are also different. Spherical musket balls leave trumpet-shaped wounds. They are widest at the point of entry and taper steadily down in diameter as the ball slows down and loses energy. By contrast, modern bullets leave cavities of a completely different shape:

Cavity left by a 5.56 mm. bullet.

The above image shows the cavity left by a NATO 5.56 mm. bullet in ballistics gel. As you can see, the bullet first creates a smaller hole in the beginning as it enters the target, but as it moves deeper into the target, it starts to tumble and fragment and leaves a much wider hole than the bullet diameter as it moves further in.

The tests also measured the protection offered by body armor. Modern mild steel plate of 3 mm. thickness of the same steel grade as those used for the penetration tests tabulated above, was lined with two layers of linen and then placed before a gel block. The entire target was mounted at a distance of 9 meters. The flintlock musket from Austria that was made in the second half of the 18th century, was fired again. Remember that this same musket had left a 369 cmcavity at an unprotected target at the same distance earlier. When fired at the protected target, the bullet did manage to penetrate through the metal and linen and entered the ballistics gel. However, it only penetrated for a short distance and left a cavity of 25 cm3. The bullet and the armor plate both splintered and some of these splinters penetrated into the gel block up to a depth of 80 mm. (or about 3.15 inches).

Incidentally, the testers also fired the flintlock pistol made in Ferlach in the 1700s, into a gel target with no protection at the same 9 meter distance and it left a cavity of about 23 cm3. This shows that the 18th century flintlock pistol fired at an unprotected target produced a wound pretty similar to the wound produced by the 18th century musket fired at a protected target.

The most interesting result of the Austrian tests involved a pistol shot at a breastplate made in the 16th century, at a distance of 8.5 meters. The breastplate was part of an armor set made to protect horses. It was manufactured in Augsburg sometime between 1570 and 1580 and made of mild steel, which was cold-worked. The thickness of the plate was approximately 2.8 to 3.0 mm throughout and had a Brinell Hardness Number of 290. The plate was mounted on a sandbag, covered with two layers of linen cloth, to simulate what a typical knight on the battlefield would wear. The pistol used for this test was the wheellock pistol made in Nuremberg ca 1620, firing a 12.3 mm. ball weighing 9.56 grams. At the point of impact, the ball was measured traveling at around 436 meters/second. The ball completely penetrated the breast plate, but it lost all its kinetic energy in doing so. The ball became heavily deformed, lost about 24% of its mass and got stuck in the linen cloth. No part of the ball managed to penetrate to the sandbag and there were no secondary splinters from the armor to cause any damage either. This means that our 16th century knight would have probably survived a pistol shot at close range with nothing more than a few bruises on his chest. This shows that the 16th century armorers actually had some pretty good skills and understood cold-working techniques well to provide such hard armor.

In our final installment of this series, we will study the accuracy results of the same weapons.

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