by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • The mostest-fastest pellet gun!/li>
  • The mostest-powerfulest
  • How to generate power
  • The deal
  • What does this mean?
  • Summary

I am at Sig today, so I won’t be able to comment as much as usual. I have airguns to test, but today I thought I would do something different. Many of our readers have gotten into modifying their guns, so I will address that today. What works, what “works” and what doesn’t.

The mostest-fastest pellet gun!

There are those who want to see just how fast a pellet can be propelled, so they put together a science experiment that uses helium as the propellant gas. They looked on the periodic table and discovered that helium is the gas with the smallest atom that is safe. Hydrogen atoms are smaller, but they remember the Hindenberg disaster.

They cobble up special fittings to connect a helium tank to their airgun. Ever wonder WHY certain gasses like oxygen and helium come in tanks with fittings that don’t couple with ours? It’s not a mistake. The fittings for those gasses are intentionally different that ours for safety reasons. That still doesn’t stop someone who works at a hospital from stealing an oxygen tank and making the fittings to fill their airgun. Then they find out why that’s not such a good idea.

oxygen fire
An air rifle that was operated on pure oxygen.

If they live through the experience, they become spokesmen for the DON’T MISUSE OXYGEN campaign.

Every few years I am contacted by someone who has discovered that helium is a thinner gas that flows faster through a valve and increases pellet velocity. They invariably think they are the first to discover this, which is similar to a troop of Cub Scouts exploring the wilds of New York City’s Central Park. It may look raw to them but lots of folks have already been there.

What these people who are after speed don’t understand is, speed is not why most people shoot airguns. It might be a passing interest, but most airgunners come to realize that hitting the target is far more satisfying. And, if there is one thing these speed guns don’t do well it’s hit what they shoot at. Either that or the entire ensemble of stuff required to do the deed occupies the rear seat of a car and weighs more than the shooter. And it costs as much to shoot as a centerfire rifle shooting commercial ammo.

By the way, helium also leaks readily. Your PCP that holds air for years may leak down in hours when filled with helium.

I’m not telling anyone that this isn’t an interesting pursuit. I’m just saying is isn’t mainstream and I doubt it ever will be.

The mostest-powerfulest

A close companion to the speed freak is the power monger. He is after the highest number of foot-pounds (or kilogram force-meters per second — because these guys live everywhere) his airgun can generate. There is actually a large segment of the big bore airgun camp that does nothing but shoot their guns through chronographs, trying to keep the power bar raising!

How to generate power

Power in a projectile is a factor of both velocity and weight. Velocity increases power rapidly, as shooters were taught by Roy Weatherby, the “High Priest of High Velocity,” back in the 1940s and ’50s. But velocity is not the only thing that boosts power

Weight also increases power in a projectile. And weight also does something velocity does not do — it increases penetration.

Elmer Keith was perhaps the best-known proponent of heavy bullets. Though diminutive in stature, Keith liked his big bullets and wrote about them a lot. And, he had an acolyte in Art Alphin, the founder of the A-Square Company, LLC. When Art and I served together in Germany in the 1970s, he told me his dream was to go to Africa and hunt the Big Five — the five African game animals considered the most dangerous to hunt on foot. They are:

African Lion
Rhinoceros (usually the Black Rhino)
Cape Buffalo
African elephant

We linked up again at Fort Knox several years later and I saw Art at the nearby Knob Creek range, shooting a .458 Winchester Magnum off a bench! You have to appreciate that Art didn’t weigh more than 160 lbs. in those days (I was lighter then, too), and to see this little guy firing round after punishing round from a bench made me wonder. I have shot a .458, but I would never consider doing it from a benchrest!

Turns out Art had lost a Cape Buffalo in the African bush after hitting him with a .458 Winchester. So he resolved to never allow that to happen again and A Square was born. You may not have heard of the company, but many of you know of the .577 T-Rex cartridge. The .458 Winchester develops just over 5,000 foot-pounds, depending on the load. The .577 T-Rex develops 10,180 foot-pounds! If that doesn’t phase you, type .577 T-Rex go Boom into You Tube and watch the video.

The deal

Here’s the deal — move the heaviest projectile you can as fast as you can and you will get the greatest energy possible from that projectile. Why do I say it that way? Well, as projectiles increase in weight they also increase in size. The bore diameter keeps their width in check, so the length has to increase. The ultimate horsepower warriors end up with long bullets their guns cannot stabilize, and eventually they reach the limit of bullet length that can be loaded. The SAD thing is — it’s all for naught! It’s a meaningless pursuit, because it gets you nothing useable.

The same Elmer Keith who loved his big bore double rifles also acknowledged that a pistol bullet will go all the way through a cow, head to tail. In other words, a .44 caliber pistol bullet fired at 900 f.p.s. from a Colt Single Action revolver will be just as lethal to large game like bison as a 500-grain .458 bullet moving at 2,500 f.p.s. Just as lethal because neither bullet kills by energy. Both kill by penetration and blood loss.

Now, the .458 bullet does have a big advantage. It will break bones that the pistol bullet will not break. It keeps on going when things get in the way. So, it may do more damage to the animal as it passes through. That’s why big game hunters shoot .458 Magnum rounds. But the reverse is also true. Bison have been killed with .45 Colt bullets that produce less than 700 foot-pounds.

What does this mean?

The application of all of this is pretty basic. Big bore airguns kill by one main method — loss of blood. Brain shots are also very lethal, but they require pinpoint accuracy, because the brains on game animals are not that large, plus many animals like pigs and Cape Buffalo, are protected by thick bone plates. Unless you are positive of the shot, a brain shot is not the way to go. Blood loss is slower but more reliable.

A big bore airgun that develops 250 foot pounds or more and is .45 caliber will work for smaller deer, as long as it is accurate. Drop back to .357 caliber and you better increase the power by at least 100 foot-pounds to get the penetration you need. Lighter bullets don’t penetrate as far. Also, the blood loss will be slower from a smaller diameter bullet. This is why I do not recommend .30 caliber big bores for deer-sized game. Sure, they will work, but if you have understood this report you’ll see why they aren’t the best choice.


If you really want to hunt game, look for a big bore with proven accuracy. I recommend staying with .45 caliber or larger.