There is a controversy concerning the performance of pellets and round lead balls that has been around for more than a decade. The round ball advocates tell us that round lead balls out-penetrate lead pellets by a dramatic margin. A second concern has to be relative accuracy. We already know how accurate certain lead pellets are – if the round ball cannot keep pace with them, any extra penetration is a moot point. You have to hit what you shoot at, first of all.
TEST ONE – PENETRATION
To resolve this question, I decided to conduct a simple test: Shoot both pellets and round balls into a transparent medium and see which penetrates the best. The medium is one I have used in the past. It’s a Neutrogena facial bar, and it’s large enough to absorb hits from air rifles up to about 15 foot-pounds. No claim is being made that Neutrogena soap resembles animal flesh in any way – this isn’t a test for that. It’s simply designed to measure the relative penetration depths of different projectiles in a standard medium. The density of the bar will give a good comparison of the projectiles while not allowing them to shoot completely through. The fact that it is transparent allows us to see the relative penetration, side-by-side, without distorting anything by cutting the bar open. This test will be conducted in .177 caliber only. That may seem limited to some shooters, but the relative penetration characteristics should remain the same regardless of caliber. The test should also hold for both high- and low-powered rifles. But, just to be sure, I’ll use one of each. A CZ 631 breakbarrel will be the low-powered gun and a TX 200 will be the high. Since this test is about penetration, we are also testing a pointed pellet with the other two projectiles. A lot of folks think that the pointed pellet’s shape gives it an advantage in penetration, so this test should prove once and for all who is right. To keep the test as fair as possible, I tried to use pellets and balls of similar weights. A round .177 ball weighs 8.7 grains and there isn’t much that can be done about it. For the ball to be heavier, it has to increase in size, which will make it too large to shoot. Pellets, on the other hand, can be made either long or short with skirts that are either thick or thin. A .177-caliber lead pellet can be as light at about 6.5 grains or as heavy at 11.5 grains. That’s a pretty wide range and the heavier pellets will have more momentum, which means more penetrating power. So we kept the weights relatively close for all three projectiles.
Conducting the penetration test
The Neutrogena bar is laid on clean paper inside a steel Outer’s bullet trap. If any pellet escapes the bar, it would have nowhere to go but into the trap. The muzzle of the rifle is held against the bar for every shot. The barrel is held so that the flight of the pellet will be as centered in the bar as possible. Any angularity might allow the pellet to escape the bar, especially when the high-powered rifle is used. Also, I wanted the paths of the pellets to be as close as possible to parallel with each other.
Before the first shot is fired, each rifle is fired five times to bring the piston seal up to optimum performance. From experience with hundreds of chronograph tests, I know that this is adequate to get the rifle performing as it should.
The photos leave no doubt about it – round balls do penetrate deeper than domed pellets and pointed pellets. The reason is seen in the narrow wound channel left behind the ball. It looses energy at a slower rate than either of the pellets, making it less desirable for thin-skinned animals like chipmunks and small birds. But if you really need penetration on tough animals like crows and larger mammals, round balls may be the way to go. The bar was not restrained in any way. Hits from the CZ 631 moves the bar by several inches; the TX 200 slams it clear back into the back plate of the bullet trap, except when the round ball passes completely through.
TEST TWO – ACCURACY
I also shot all three projectiles in both rifles at about 15 yards. This shows the relative accuracy, but the results are not what you think. Instead of ruling out the round ball completely because it isn’t as accurate as a pellet, you can establish the range at which you can hold a group sized to the kill zone of your quarry. For a crow, that might be 1.5 inches. For chipmunks, it’s an inch or less. The distance at which you can hold a five-shot group that tight is the range at which a projectile can be used.
Round balls out-penetrate diabolo pellets. They can be as accurate as most diabolos in some airguns. Use them on hard targets, where penetration is desired over energy transfer – and hold your maximum range to the distance at which you can hold a group in the kill zone of your quarry.