“It’ll hit like a .22!”
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Sheridan Blue Streak
- Flattening a ball
- Universal law
- So what?
- Oh, fudge!
When I was a boy in the mid-1950s, that was the catch phrase of the day, “Pump it up 20 or 30 times and it will hit like a .22!” The people who said such things were all older than me and many of them were adults, so of course I knew it was true. Pump that Benjamin rifle 20 or 30 times and it will hit like a .22. It had to —right? I mean, if you pumped it just 5 times it would go through both sides of a tin can, which in my day was made of steel plate. The title tin was a holdover from the early 1800s when tin-plated steel was used for the can’s body and a lead and tin solder was used to seal the seam of the can.
When I made cans at National Can in Sunnyvale, California in the 1960s, there was no tin anywhere in the can. The steel was sheet steel and the seams were soldered with lead — I know because I cut the steel and kept the solder baths that sealed them filled and fluxed. If the contents of the can were going to be acidic, such as tomatoes or soda pop, we sprayed the inside of the can’s body with a lacquer coating to keep the contents separated from the steel.
The point is, those cans back then were tough! They were nothing like the thin aluminum cans we see today. They served us well as makeshift chronographs. A powerful BB gun could shoot through one side of a can. Benjamin’s 30/30 (1962-1976) advertised that it could shoot through both sides of a 5-gallon steel pail!
Benjamin’s 30-30 was a powerful CO2 BB gun.
Benjamin touted it as being able to shoot through both sides of a 5 gallon steel pail. That was the criteria for power in those days.
Sheridan Blue Streak
Sheridan said it in a different way. They showed “controlled penetration” in wood. One-inch, to be exact. They did mention the wood was soft pine, and indeed a Supergrade or Blue/Silver Streak will penetrate that far if the wood is truly soft. Hard pine is a different story, and we discovered that to our chagrin!
Sheridan ran this ad for many years. This one is taken from the 1956 edition of Smith’s Standard Encyclopedia of Gas, Air and Spring Guns of the World. by gun writer W.H.B. Smith.
The point is — we didn’t have chronographs in those days. Chronographs were only owned by big laboratories and took several people to operate. So we did the best we could to determine power, and that turned out to be penetration.
Flattening a ball
A century and more earlier, the criterion for determining airgun power was how flat the ball would become when shot against a hard steel surface.
This drawing appeared in the November 6, 1824 edition of the London Mechanics Register. It is a drawing of the lead ball fired from a Perkins Steam Gun against an iron plate. It was the way to show power almost 200 years ago — a time before chronographs and cameras existed. From Gas, Air and Spring Guns of the World.
Roughly 60 years later an airgun manufacturer used the same method to show how the power regulation screw on their guns that controlled the hammer spring tension affected power in a Giffard-type rifle.
This photo is from a CO2 gun’s advertisement. It shows how the power of the gun can be controlled. From Gas, Air and Spring Guns of the World.
If you are a long-time reader of this blog you may remember that we also talked about this method of determining airgun velocity. It is a practice that airgun maker, Gary Barnes, called Splatology.
Splatology refers to the observation of pure lead balls that are fired against a rigid plate — producing what Barnes referred to as “splats.” He rediscovered what the airgun makers from history had known — that lead balls deform along rigid parameters as their impact velocity increases. But Barnes had access to something the ancients never did — a chronograph. He could also know the velocity of the splat to within a very precise amount. And he did something amazing with that information.
Barnes created a physical splat graph of lead balls that had deformed at precise velocities. It was two boards that charted the deformation of balls impacting at incremental velocities from very low speed to as fast as the splats held together. Any higher and the ball was reduced to lead dust and particles too small to be of any value.
This first board takes balls from 0 f.p.s. to 452 f.p.s.
This second board takes balls from 429 f.p.s. to almost 700 f.p.s. At that velocity the balls break into small fragments and this process can’t be used any more.
This report began as an informal statement, “Pump it up 20 or 30 times and it will hit like a .22!” That was completely untrue, but in the day when it was said nobody ever challenged it. So it became accepted as fact.
In truth it is nearly impossible for a pellet gun that shoots a diabolo pellet to ever come close to the power of a .22 rimfire cartridge. A standard speed .22 long rifle cartridge can launch a 40-grain lead bullet at between 1,050 and 1,100 f.p.s. That generates a muzzle energy of between 98 and 108 foot-pounds. What do we know about smallbore airgun energy? We know that the AirForce Condor in .25 caliber can produce about 105 foot-pounds at the muzzle when it shoots the heaviest diabolo pellets currently available. And that level of energy has only been possible in the last 5-10 years. Before then, no smallbore air rifle produced anything like that kind of energy.
The Benjamin pump guns people were talking about in the 1950s never got above 20 foot-pounds and even that was a real stretch. Fourteen foot pounds was more like it.
Barnes also discovered that the size of the lead ball made no difference in determining how it deformed. The form of the splat was a constant regardless of the size of the ball that created it. That turns out to be as important to determining velocity as astronomers’ “standard candle” is for determining distance.
If you have to ask you aren’t getting it. The reason this is important is because people are unreliable sources for accurate information, and you can include me in that statement. That’s why I show you the targets I shoot. It’s also why I often shoot 10-shot groups instead of 5. And I still make a lot of mistakes. What I try not to do is promulgate beliefs because they sound good or, “That’s just the way it’s always been.” It’s why in 2011 I tested Velocity versus accuracy and determined that supersonic flight does not affect a pellet’s accuracy adversely. I still hear people saying that it does and I don’t bother correcting them because the 11-part report has been online for 8-1/2 years. You don’t have to believe it, but I did tell you what I did to test it. None of the good old boys who said overpumping a Benjamin will make it shoot like a .22 did that.
In reading Part 11 of the velocity report mentioned above I discovered that I was planning to do even more with it. Well, no time like the present!
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