by Tom Gaylord
Writing as B.B. Pelletier
Below is a discussion about how a big bore airgun kills game. If your interests are in smallbore airguns and appropriate game for those calibers, scroll to the end of this article for links to another article and a couple videos.
If you’d like to comment on this, please go to the current day’s blog to do so — more people will see it, and we welcome off-topic comments.
• What constitutes a big bore?
• The one unified law
• Respect for game
• Big bore airguns are very different
• There are exceptions
• A big truth about big bore bullets
• Hydrostatic shock
• Why you need to know this
• Other airgun hunting resources
This will be a detailed discussion that may not be suitable for people who feel uncomfortable reading about or talking about killing animals.
What constitutes a big bore?
I’m asked this question all the time. What makes an airgun a big bore? I started answering this question before many others even knew what big bore airguns were, and I’ll continue to answer it in this same way. There are 4 common smallbore calibers — .177, .20, .22 and .25. Anything larger than a .25 is a big bore. Sounds simple, but it invites the barracks lawyers to chime in. There are airguns today that shoot .257-caliber conical bullets, and isn’t a .257 technically a .25? Yes, it is. This is where my simple definition breaks down a little.
But there’s more to it than that. A hundred fifty years ago, hunters had no difficulty understanding that a rifle that shot .40-caliber balls or larger was suitable for hunting whitetail deer. In a pinch, they would even use a .38-caliber rifle, but .40 caliber was the place they wanted to be for large, thin-skinned, non-dangerous game. You won’t find this written in any book that I know of; but if you read a lot of shooting history, it’ll come out.
So, the hunters of old knew that the bottom line for a rifle for larger game (the smallest you could use and expect success) was around .40 caliber. And .45 caliber was even better. When the ball got that large, there was no mistaking where things stood.
Then, conical bullets came along (1860?) and muddied up the water. Suddenly, a .32-caliber rifle shooting a heavy conical bullet (like the .32-40 in 1884) was sufficient for deer, but a .38 caliber shooting conicals (the .38-55, about the same time) was even better. And, just when that was being digested by the sporting public, smokeless powder came on the scene and bullet velocities doubled. At that point, .30-caliber rifles (like the .30-30) could take deer; and, soon, even .25-caliber rifles (such as the .25-35 Winchester) were considered marginal.
The one unified law
Many of today’s shooters don’t even know what a .25-35 Winchester cartridge is. Yet, they want one unified definition for a big bore airgun, but none exists. No single definition can be applied — especially, if the people applying it refuse to understand basic ballistics. If they think that the title “big bore” conveys some mystical killing power to any airgun, they’re sadly mistaken. Yes, I can tell you what a big bore airgun IS, but that, by itself, tells you very little about what it can DO. To know that, we have to understand how game is killed.
In the olden days, a .40-caliber ball was considered big enough to take deer — not because of its energy, which was almost nil, but because of its size. And projectile size is what I’m talking about here.
Respect for game
When I studied for my German hunting license in the 1970s while serving there in the U.S. Army, I learned how much the German hunters respect the game they kill. Besides learning a specialized vocabulary of German words that apply only to hunting and demonstrating proficiency with a rifle, we had to know how to treat game with respect. For example, whenever I killed a roe deer, I put a sprig of pine in its mouth as a ceremonial “last bite.”
Sure, such things are for the hunters and not for the game whose lives have already been taken, but what they do is remind the hunter that this was a living being that enjoyed life until the end. I think these small ceremonies keep most hunters from becoming crass. That has everything to do with this discussion.
Big bore airguns are very different
Most hunters are surprised when they shoot a game animal with a big bore airgun. They’re surprised because the animal doesn’t fall down at the shot. Typically, they stand for several minutes where they were hit . . . as they slowly expire (die) from blood loss. It’s so different from anything they may have experienced while hunting with modern firearms.
When a large game animal is hit with modern expanding bullets traveling at supersonic speeds, it can drop instantly in its tracks. Granted, that doesn’t happen often, but it does happen. At the very least, a well-hit animal that’s hit with a modern expanding bullet runs only a short distance before piling up. Thirty seconds is usually the longest you have to wait before it drops — when the animal has been hit well. Modern centerfire bullets have caused hunters to expect quick results that big bore airguns do not and cannot give.
Hunting with a big bore airgun is very similar to hunting with a muzzleloading rifle that shoots lead balls or bullets — not one shooting modern jacketed softpoints with sabots. It’s also similar to hunting with a bow. The game often stands in one place, looking around like it hasn’t been hit. Or if it does run, it runs fast and far and has to be tracked. The secret is to not follow the game right away. After the shot, wait about 10 minutes for the animal to stop running and start stiffening up. They’ll usually bed down at this point and won’t be able to get up again.
There are exceptions
Of course, there are exceptions to what I’m saying about modern bullets and game. I’ve had them happen to me — animals that appear to be hit well, but last much longer than they should. The hunting archives are full of stories about game that refused to die. But you have to recognize these for what they are — exceptions to what usually happens. In general, a modern bullet of the correct size and power will very quickly dispatch an animal that is hit well.
A big truth about big bore bullets
Here’s a truth that escapes many modern hunters. A .45-caliber lead bullet generating 250 foot-pounds of energy will kill a medium-sized animal such as a whitetail deer just as dead in the same amount of time as a .45-caliber lead bullet that generates 1,500 foot-pounds of energy. That’s because most of the more powerful bullet’s energy is not expended in the animal — it slips right through and keeps on going! Most of the energy is excess to your needs.
Unless there’s a large bone in the way, or the animal has a particularly tough hide, you don’t need to hit it with a lot of energy. These heavy lead bullets don’t kill with their energy — they kill with blood loss. This is why relatively light round balls kill large game so effectively.
New big bore hunters are fascinated with hollowpoint lead bullets — thinking that the expansion of the bullet inside game transfers more of the bullet’s energy to the animal. But it isn’t the energy that kills — it’s the loss of blood. So, a .45-caliber solid bullet kills just as fast as a hollowpoint bullet that mushrooms out to .75 caliber. Once the hole in the animal is big enough, it doesn’t make much difference if it grows any larger. The damage has been done.
What I’m leading up to is this: A 405-grain .458-caliber bullet is fine for the largest game. If I think I need it to penetrate a heavy bone or a thicker hide, the 405 is the way to go. But if I’m hunting thin-skinned whitetails or something similar (javelinas, coyotes, mountain lions, etc.), I want a much lighter bullet that has the advantage of a flatter trajectory.
The 405-grain bullet would be perfect for American elk (wapiti), red deer and bison. We know from actual field experience that it will pass completely through even these massive animals when it impacts on one side, such as with a classic heart/lung shot. That happens even when the bullet is fired from a 500 foot-pound rifle. Then, the process of bleedout begins and the animal drops several minutes later, when blood loss has its effect. This is something archers understand all too well. But many who come into big bore airguns from the firearm side are used to hydrostatic shock.
Hydrostatic shock is the shock wave that passes through the liquid-filled tissues of an animal when hit by an ultra-high-velocity bullet. This shock wave is devastating to the animal’s nervous system and can sometimes cause near-immediate death. Many hunters are so accustomed to this effect that they cringe when they see how long it takes a bullet from a primitive rifle or an arrow to drop an animal. That slow performance is exactly what you can expect from a big bore airgun bullet.
Why you need to know this
Many people would like to learn to hunt, and big bore airguns are starting to look like an easy way into the sport. That’s fine — as long as you know what you’re getting into. At the end of your hunt, an animal is going to die and it’s going to take a long time to do it — especially if you’ve hunted only with modern centerfire rifles, or the only hunting you’ve ever seen is what’s on television.
Believe me, the hunting shown on television is heavily edited! If the game happens to drop instantly when shot, they show it — but if not, they edit in some tracking, along with conversation to get your mind off what’s really happening. If it takes 12 minutes for an animal to die, you will only see about 20-30 seconds of that. I happen to agree with that approach, because people don’t need to see the suffering in their living rooms.
But, if you decide to go out into the field to hunt, then I want you to know what you’re going to see. I hunted extensively when I was younger, and everything I’ve described here I’ve seen many times over. But I’ve also seen a first-time hunter confronted by the truth. And he was shocked. That wasn’t pleasant.
Just understand that when you do decide to hunt with a big bore, the results will probably look a lot different than you might have imagined.
Other airgun hunting resources
If you’re interested in hunting with smallbore airgun calibers, read Hunting with airguns, a general article that touches on the common types of pests and game usually taken with .177- to .25-caliber airguns.
A couple videos you may find helpful when selecting a hunting airgun are: