by Tom Gaylord
Writing as B.B. Pelletier

A history of airguns

This report covers:

  • Smallbore calibers
  • Confusing lines
  • Other calibers
  • .12 caliber
  • .175 caliber
  • .180 caliber
  • .21 caliber
  • .21-1/2 caliber
  • A couple really odd sizes
  • Summary

Before we begin, I am leaving for Las Vegas and the 2016 SHOT Show today. I will have limited time to answer questions from readers, so I’m asking the veteran readers to help out until I return to following Saturday.

Smallbore calibers

We know there are 4 popular smallbore airgun calibers in use today. These 4 are not mandated by any regulation, nor controlled by any specification. Nothing makes them smallbores, except for the existence of big bores. In other words, they are smallbores by default — because they aren’t big bores.

The 4 smallbore pellet calibers we know today are .177 (4.5mm), .20 (5mm), .22 (5.5mm) and .25 (6.35mm). The round ball calibers are steel BB, which is .171-.173 (4.3-4.4mm). Anything larger than .25 caliber is commonly called a big bore, though there are no hard and fast rules about it. In fact, there are .25 caliber guns that qualify as smallbores and other .25 caliber guns that qualify as big bores. Confused?

Confusing lines

If a .25 caliber airgun is made primarily to shoot diabolo pellets, we call it a smallbore. But if it is made to shoot .25 caliber rifle bullets, we refer to it as a big bore. Some people call the big bore .25 a .257, but that’s the size of both the pellets and bullets, so the definition is muddled.

Other calibers

Okay, now that we have that out of the way, what other smallbore airgun calibers have existed? I’m excluding big bores from this discussion because a big bore can be any size you want. The Vesuvius dynamite cruiser had big bore airguns of a huge caliber! Let’s just stick with smallbores for today.

.12 caliber

There have been many .12 caliber airguns. The true caliber is .118, but we commonly round it up to .12. These are the guns that shoot number 6 bird shot and also the .12-caliber copper-plated steel BBs that Daisy once made for their early Targeteer pistol.

12-caliber gun
The Kruger single shot pistol made by Wamo, the Hula Hoop people, used toy caps to propel a .12 caliber lead ball.

The Daisy Targeteer was perhaps the most prolific and best-known of the .12 caliber airguns. It evolved into a BB pistol in the 1950s, but until then it fired copper-plated .118-caliber steel shot. The gun is better-known today than the shot it fired, which is seldom seen outside an airgun show.

Targeteer gallery
This Targeteer came packaged with a plastic shooting gallery. Two red, white and blue metal tubes of shot fit inside the gallery feet to keep it stable.

Targeteer shot
Real Targeteer shot is seldom seen today.

Besides the Targeteer and Wamo guns, this caliber also was used in the Bullseye and Sharpshooter line of catapult guns that lasted from 1923 until the mid-1980s. Those guns are low-powered, so having a very light projectile is quite an advantage.

.175 Caliber

In the early part of the 20th century, Daisy decided to reduce the size of their lead BB shot from 0.180 to 0.175-inches. It saved lead, which matters when you are making and selling millions of shots a year. It also sped up the guns, which meant Daisy could reduce the size of the mainspring and make the cocking effort easier.

There is a range of BB guns made from about 1900 to 1925 that should be using this size shot. Of all the odd sizes, this is the most difficult size to find today. If you fins and Air Rifle Shot of the3 right size, it’s collectible and too valuable to shoot. Everyone uses 4.4mm lead balls in these guns today.

.180 caliber

This is the original BB-gun caliber. It started out as shotgun bird shot, size BB (smaller than size B and larger than size BBB). Seventy years ago shot in that size was still pretty easy to come by, but it has gone out of favor among shotgunners of today, to the best of my knowledge. Original air rifle shot in this size is a collector’s item.

.21 caliber

Both Quackenbush and Crosman made .21 caliber airguns and ammunition. Quackenbsh made lead slugs of both the burred type (wider lip at the base) and also felted (piece of felt glued to the base) variety. Indeed, many Quackenbush airguns were .21 caliber. Even their darts came in this odd size.

Crosman made their model 121 GC (compressed gas) target rifle in .210 caliber. That was presumably so they would be the only supplier of the ammo for the indoor target ranges they were selling to companies.

Crosman CG
This Crosman CG is a .22 caliber, but the model 121 CG that was provided in Crosman’s shooting galleries of the 1940s looked identical. Sadly, many of those guns have now been converted to .22 caliber — just to solve the ammunition problem.

.21-1/2 caliber

What? Twenty-one and one-half caliber? Yes. Quackenbush made a combination gun that was both an air rifle and a .22 rimfire rifle. The firing pin was carried in a compartment in the wooden stock. While it fired regular .22 rimfire cartridges when set up as a firearm, it shot .215-caliber burred or felted slugs. This was never a popular pellet size, though it was produced from the 1880s until the 1920s.

A couple really odd sizes

I have heard that Jim Maccari experimented with a .14-caliber pellet rifle. I don’t know how many he made or what he did for ammunition. Fourteen caliber has been suggested by others in recent times. It would be a way to reduce the amount of lead in a pellet, which is becoming a cost concern, plus it would give some advantages in the velocity department. Rifling a .14-caliber barrel might prove tricky, though with modern rifling methods it might be more possible today than ever before.

I’ve also heard of experiments with a 6mm (.243 caliber) pellet. It’s so close to a .25 that there doesn’t seem to be much room for this caliber, but sometimes all it takes is a new caliber to stimulate the market.


Well, there you have it — all the smallbore calibers that airguns have come in since they started in 1886. There are other calibers, such as .28 that a lot of 19th century gallery guns were made in, but because that is larger than the .25 caliber upper limit I established, I decided to stop here.