Does Speed Kill?

Does Speed Kill? | Shooting Sportsman Magazine
Photo by Dale Spartas/spartasphoto.com

Speed kills.” It’s a simplistic declaration about shotshells commonly repeated in the shotgunning world that I’ve touched on previously in passing but not in the ballistic detail it needs for full understanding.

Let’s examine the technical accuracy and veracity of the claim that high velocity in shotshells is the way to improve killing performance. It’s an idea that sells, because in the world of bullets dominated by aerodynamically efficient projectile shapes, increasing the velocity of such projectiles at the muzzle can result in significantly improved retained energy downrange. It’s also because most bullets, compared to individual shotshell pellets, are relatively large with substantial mass—and once launched they don’t slow quickly.

But the shotgunner’s ballistic world is profoundly different than that of the rifle or pistol shooter. Currently the vast majority of bird hunting and clay target shotshell projectiles are ball-shaped. The physics of spheres, or balls, is significantly different from the physics of bullets. This is something the “speed kills” advocates do not understand . . . or possibly choose to ignore. The most important difference is that balls are much less aerodynamically efficient than bullets. Because of this, the faster a ball is initially launched, the more rapid is its deceleration.

Advertisement

Therefore, while it is of great value to increase the muzzle velocity of a bullet by, say, 150 fps, it is of minor value to increase the muzzle velocity of a bird-shot-size ball a mere 150 or even 200 fps. That’s because such a small ball simply sheds the vast majority of that couple-hundred-fps muzzle-velocity increase so quickly that very little of the original velocity and pellet-energy increase are retained by the time it travels a mere 40 yards. And those balls shed their velocities even quicker if they are soft pellet types like lead or bismuth and suffer deformation before leaving the muzzle.

Let’s look at an example. If a No. 2 (.150") steel pellet is traveling 1,300 fps three feet from the muzzle (the distance shotshell velocities are measured in the US), that pellet at 40 yards has slowed enough to retain only about 2.18 foot-pounds of energy. Increase its three-foot velocity to 1,450 fps, and that No. 2 pellet now retains approximately 2.40 foot-pounds of energy. This is only a 10.1% increase at that distance. At 1,500 fps launch velocity, the pellet retains about 2.48 foot-pounds (13.8% more), and at 1,550 fps it retains 2.55 foot-pounds (about 16.9% more). Retained energy could be increased even more by increasing velocity, but 1,550 fps is about the practical limit of most shotgunners’ tolerance of the resulting greatly increased recoil.

I assure you from being responsible to approximately 35 wildlife agencies and hunter conservation organizations worldwide plus four US ammunition manufacturers that sponsored my lethality research regarding taking gamebirds with lead and nontoxic shot during a 40-year period and the subsequent necropsies of some 28,000 of those birds taken at measured distances, an increase in per-pellet retained energy of less than 20% was never found to significantly increase penetration on birds. These are proven scientific facts that I published individually or with co-authors in peer-reviewed professional journals and special reports to the sponsoring ammunition manufacturers and wildlife agencies.

Conclusion: It is both false physics and bogus to argue or promote unconditionally that speed kills insofar as bird and clay target shotshell ammunition is concerned. The mass of research summarized above proves conclusively that modest launch velocities of about 1,200 to 1,300 fps with lead, bismuth, HEVI-Shot or other tungsten-composite types and 1,300 to 1,400 fps with steel are all that is needed for game-killing and target-busting performance. (This provided the correct pellet type and size are used and the proven minimum pattern count needed can be produced at the distance the bird or clay target is being struck.)

Now there is a way that is both scientifically proven and supported by physics to increase the lethality of shotshell loads containing ball-shaped projectiles. And that is simply to go up one pellet size of the same pellet type if one desires increased penetration on gamebirds or better clay target breaking. Let’s look at an example. If at 1,300 fps launch velocity one is willing to go up to a No. 1 steel pellet (.160") from a No. 2 steel, the No. 1 pellet will retain at 40 yards about 4.70 foot-pounds of per-pellet energy (compared to the No. 2 steel’s 2.18 foot-pounds). That is a whopping 116% increase in retained energy. And that will result in significantly increased penetration and therefore lethality on birds. And, no, the pellet count of the load will not be significantly reduced by going up just one pellet size. This example applies to all pellet types and sizes.

Advertisement

Conclusion: The increase of merely one pellet size of the same pellet type driven at the same velocity level will always significantly increase retained energy and penetration on birds. Lethality is significantly increased because of the larger pellet’s significantly greater mass.

What’s more, staying away from ultra-high-velocity loads will avoid the pattern-degenerating effect of high velocity on pellets. And it will also save you from suffering the awesome recoil levels of such loads—which is especially helpful to older shooters. Most 1,450-plus fps nontoxic loads in 12 gauge develop recoil levels well into the 40- and 50-something foot-pound range. That’s a young shooter’s tolerance range—and then, many would argue, only if mitigated by shooting a gas-operated autoloader.

So keep all this in mind when buying factory ammunition or reloading your own. You do not need ultra-high velocities for bird hunting or clay target shotshells. The manufacturers that are now marketing ultra-high-velocity shotshell loads also still offer traditional modest-velocity loads, although the selection has shrunk.

To consult with Tom Roster or to order his new Advanced Lead & Bismuth Shot Handloading Manual, his HEVI-Shot and HW-13 reloading manual, or custom loading data, contact Tom Roster, 1190 Lynnewood Blvd., Klamath Falls, OR 97601; 541-884-2974, [email protected].


Buy This Issue!


Written By
More from Tom Roster

Science & Steel Catch Up with Doves

Taken for granted by hunters outside the South for many years, shooting...
Read More

Leave a Reply

Your email address will not be published.