Diana 23: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

Dioana 23
Diana 23.

A history of airguns

This report covers:

  • A stripper
  • The rifle
  • Two versions of the later rifle
  • Trigger
  • Breech seal and locking detent
  • Sights
  • Cocking
  • What is it good for?
  • Summary

This report should be titled, “By any other name” because the airgun I’m writing about doesn’t say Diana anywhere. It says Gecado, Mod. 23. I know it is a Diana because I have paid attention to Diana air rifles for the past four decades, or so. They can also be named Hy Score, Winchester, Peerless, Original, Milbro, RWS, Geco (of which Gecado is a derivative) and Beeman. And I bet there are more names I haven’t mentioned.

Dioana 23 markings
These are the principal markings on the rifle. There is no serial number, caliber or date of manufacture.

A stripper

Decades ago a new car that was basic and was priced as low as that model would go was called a stripper. Well, the Diana 23 is the stripper of Diana pellet rifles. In the photograph above the rifle appears to be the same size as a Diana 27, but when you see them together the difference becomes obvious. read more

How powerful were the big bore airguns of the past?: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

The history of airguns

This report covers:

  • New blog section — History of airguns!
  • How powerful?
  • Wood was first
  • Iron and steel
  • How fast — Spaltology
  • Velocity of the big bore airguns of antiquity
  • Available air pressure
  • Why this is important

New blog section — History of airguns!

Today I announce a new section of the blog that will be dedicated to the history of airguns. Monday’s posting about the Rise of the BB gun was the inaugural report for the series — History of airguns. Today is the second in what Pyramyd Air and I hope will become a favorite of blog readers.

My goal is to document the history of airguns in these reports, and the really neat thing is, we will keep track of all these reports on a special page that holds the table of contents. The articles listed will be links, so all you need to do is hover your cursor and click to get there!

As the number of reports grows, they will be grouped into categories for ease of management. For example, all BB gun reports will be in the BB gun section, and so on. But, until we get a few more reports, the links will just be listed as they come.

How powerful?

Today’s report addresses the power of the big bore airguns of the past. How powerful were they and how did people living 300 years ago measure the power of an airgun? They didn’t use chronographs; those were still hundreds of years in the future. So how did people in the year 1715 gauge the power of an airgun — or for that matter, of a firearm? They started simply. They judged the force of a shot by what it could do, and they set up tests to demonstrate those results.

Wood was first

The first “test” was to see how deeply a ball fired from an airgun penetrated into a piece of wood. That’s not so different from today — is it? But wood has many problems. Should it be a living tree or wood that has been cut into lumber? If lumber, should it be green or dry? Does it matter if the shot goes across the grain or with it? Does the species of wood make any difference? And so on. As it turns out, soft woods like balsa provide vastly different results than hard woods like ironwood and hickory. And it is easier to penetrate across the grain, rather than traveling with it. Wood is not a very good way to test the power of a gun.

Iron and steel

What about iron and steel? While there are many alloys of both metals, the outcome of shooting a lead ball at them isn’t affected by those differences as much as it is with wood. This was widely accepted in the past, and testing of airgun power was tied to how deformed a ball would be after it hit a steel plate. But before we continue, you must understand that the plate the ball strikes has to be immobile for what follows to make sense. If the plate can move, some of the ball’s energy is used to move it, thus rendering the flattened ball less accurate for what comes next.

In the 1957 book, Smith’s Standard Encyclopedia of Gas, Air and Spring Guns of the World, by noted gun writer W.H.B. Smith, there is a drawing of a smashed lead ball from history. It was fired from a Perkins steam gun (ca. 1825) at an immobile iron plate 100 feet from the muzzle. The ball is shown in its original shape and also as it flattened against the iron plate. If the image in the book is life-sized, the ball measures 0.453-inches in diameter. That sounds about right for a gun of the period, though it is on the small side.

ball from Perkins gun
Ball from Perkins gun, before and after striking an iron plate at 100 feet. Image taken from Lateral Science, a scientific pamphlet published July 8, 1912. Image B is on the left and C is on the right.

I know that steam is not air, but the principal of this gun remains the same. The Perkins gun had a barrel length of 6 feet and was capable of firing 500 to 1000 balls per minute. Yes, it was fully automatic — not in the sense that a machine gun is automatic, but just as a water hose sprays water in a continuous stream, so the Perkins gun sprayed bullets. Perkins’ gun generated the unbelievable steam pressure of 900+ psi, at a time when air pressure was not able to compete. More on that in a moment.

How fast — Splatology

Before I talk about the air pressure the antique airguns generated, let’s first look at that deformed ball — for it actually tells us how fast it was traveling when it hit the iron plate. Big bore maker, Gary Barnes, did extensive testing of lead balls shot from big bore airguns in the late 1990s. He discovered that all lead balls deform the same when they hit steel plates at the same velocity. So a .32 caliber ball and a .50 caliber ball both flatten by the same amount when both hit the plate at the same speed. From this he created Splatology — the science of determining the terminal velocity (velocity at the steel plate) of a lead ball by its appearance. If you follow the link, you can read that article.

There is a quiz at the end of that report. You can take it if you like and find the answers at the beginning of the next blog.

From Splatology we know that the ball from the Perkins gun hit the iron plate 100 feet away at a terminal velocity of 560 to 580 f.p.s. So the muzzle velocity had to have been higher — perhaps 625-650 f.p.s. In other words, we can accurately know the velocity of a shot taken nearly two centuries ago! That is the upper end of power for a big bore airgun from the past. But wait — there’s more!

Velocity of the big bore airguns of antiquity

One more point before I get to the air pressure at which these antique big bore guns operated. The Perkins gun was more powerful than most airguns of its day. That means that the velocity those other guns generated was also lower. However, some of the Perkins gun’s velocity was offset by the fact that it was firing a continuous stream of bullets, where the airguns fired but one shot at a time. And some more velocity is given up because the Perkins gun used steam and not air. Air is thinner than steam and flows faster through a valve. So, even though the steam pressure in the Perkins gun might get up over 900 psi and the air pressure in true airguns of antiquity does not go that high, the muzzle velocities of the best airguns are very close to those of the Perkins gun — closer than the difference in pressures would suggest. Let’s take a look at what they worked with.

Available air pressure

There are many accounts of vintage and antique airguns operating. Most of them are unsubstantiated by facts — either in the articles or from tests that have been run to prove or disprove the claims. So, in 1998 Dennis Quackenbush approached me with an idea. Why not create a couple hand pumps that were similar in all respects to those of antiquity and test them to see what they could do?

We did just that and I published the results in Airgun Revue Number 4. And I republished an abbreviated version of that article in a three part blog report in 2008. There is far too much detail to cover here, but in that series you will discover that Dennis and I proved that the hand pumps of antiquity could generate from 750 to 850 psi — though 850 was really pushing the envelope. Theoretically it is possible for a hand pump from that time to generate pressures up over 1200 psi, but to do so the pump’s piston has to be very small.  The number of pump strokes such a pump would require to fill a reservoir to that kind of pressure becomes enormous.

Suffice to say we now know that the antique big bore airguns operated at air pressures ranging from 450 to 800 psi. The earlier guns (and pumps) from the years 1600 through 1800 probably operate at the lower end of this scale, while the guns and pumps made at the end of the 19th century are at the higher end. That means whatever velocity those antique airguns were able to achieve had to be achieved by air pressurized within these limits.

You have read in this blog that velocity is achieved in a pneumatic gun by the length of time the valve remains open and the length of time the air has to push against the pellet, which is the barrel length. Only when both of these things are optimized does the air pressure come into play. So valve dwell time and barrel length are more important than the available air pressure. If you need a refresher on this concept or if you are a new blog reader and missed this discussion, look at this report.

Why this is important read more

The stuff we do!

by B.B. Pelletier

Announcement: Shao Lin is this week’s winner of Pyramyd Air’s Big Shot of the Week on their facebook page. He’ll receive a $50 Pyramyd Air gift card.

Shao Lin wins this week’s Big Shot of the Week.

The more I read the old books about shooting and guns written by men who were born in the 19th century, the more I realize how much alike we all are — and I don’t just mean shooters, now. I mean people, in general!

Let’s begin with nicknames or handles. We have some clever ones here on this blog. But are you aware that back in the late 1800s, shooters who posted letters in their favorite shooting publications — which at that time were mostly newspapers — did the same thing?

Names like Medicus and Iron Ramrod shout out from the late 19th century with their concerns that the younger shooters who are getting used to cartridge-loading breechloaders simply do not know the rudiments of shooting like the “real shooters” who grew up with black powder! The new crop of shooters (I’m speaking of late 19th-century shooters, now) have forgotten how to measure a group with string and they want to measure the distance to their targets in yards instead of rods like real shooters do.

Then, there are the experiments they performed. Dr. Mann was the great one for this, and he kept a very compliant Harry Pope busy fashioning the testbeds for his various forays into the arcane world of ballistics. Things like the cylindrical rifle action that allowed Dr. Mann to rotate the action by degrees in a complete revolution, all while the gun was safely snugged down in his 3,000-lb. “Shooting Gibralter” vise. Or the barrel he convinced Pope to rifle after drilling and tapping eight holes through the side of the barrel near the muzzle so Mann could test the effects of releasing gas to the side so it didn’t exit the muzzle with the bullet. Pope had to lay out that rifling job so those pre-drilled and threaded holes ended up in the grooves of his gain-twist rifling and did not cut through any of the eight lands!

I got a call the other day from Dennis Quackenbush, who follows my column in Shotgun News. He became interested in my comments on the rifling twist rate of airgun barrels as it relates to stabilizing those solid pellets that I call bullets. They don’t shoot very well in most airgun barrels because the twist rate of one turn in 16 inches of barrel isn’t fast enough to stabilize them once they exit the muzzle. So, he offered to make me two test barrels — one rifled 1 in 22″ and the other rifled 1 in 13″ — to test what effects the twist rate has on pellet stabilization. I’m going to accept his offer, and we’ll have yet another look at one of the big drivers of accuracy. I’ll also test velocity using the exact same power settings, so we will have a good look at how twist rates affect velocity.

Years ago, Dennis allowed me to cut off one of his smallbore CO2 rifle barrels an inch at a time so I could chronograph the pellets coming out of many different barrel lengths. I reported those results in The Airgun Letter after completing the test, which is why I now have some sense of how long a CO2 barrel needs to be to get maximum velocity.

Then, there’s the famous Cardew experiment from their book, The Airgun From Trigger to Target, where the authors fired a spring-piston rifle in an inert gas environment that didn’t support combustion — all so they could test the power level of a spring-piston rifle that was denied the possibility of dieseling. The fact that they did the experiment was good enough. We learned that all air rifles that shoot above a certain velocity diesel with every shot. But what was really cool was how they did it — by shooting inside plastic bags!

When I worked at AirForce, we had a customer who purchased a .22-caliber Condor, then proceeded to adapt the rifle’s reservoir to a large helium tank. He could then sit at a bench and fire the rifle on pure helium. He claimed to get over 1,500 f.p.s. from his modified rifle. It was useless for anything else, but he didn’t want to do anything other than see how fast it could shoot.

Even my semi-sane buddy Mac bought a 26-inch Weihrauch barrel in .177 just so he could adapt it to his son’s Condor. He was looking for a flat-shooting air rifle and I guess he got it, because his son is now supposed to be able to keep all his shots on the round end of a soda can at 80 yards.

Let us never forget the great pogostick repeating airgun! That one is now in Vince’s protective care, awaiting his verdict on whether or not it can be made operable.

Left-eye dominance
Here’s a problem many shooters have. Their dominant eye is on the other side of their body from the side that dominates the motor skills. The most common is a right-handed person whose has a dominant or master left eye. This can be overcome in a number of ways — including tinkering! Back when Edith was shooting BRV, she discovered that she is left-eye dominant; but Gary Barnes, who made the rifle she competed with, made her an outrigger scope mount that put the scope in line with her left eye. The mount had to be boresighted for just one range; because like the pellet drop, the gun also shot to the left from the shooter’s perspective. No problem in BRV, though, because it was all shot at one distance.

Edith’s outrigger scope mount helped her sight with her left eye while shooting right-handed.

But Edith is far from the first shooter to have this problem. Take a look at the lengths a shotgun maker will go to satisfy his client.

A friend owns this shotgun with a crossover stock. It was made to aid a right-handed shooter who is left-eye dominant.

A couple months ago, I bought an unusual Schmidt-Rubin Model 1911 rifle at a gun show. This one has been carefully transformed into a fine target rifle. I could spend a whole blog on just this one rifle, but here are some highlights. The military stock has been completely reshaped into a target style with a deeply curved pistol grip. The bolt handle that used to be two cones of red plastic (yes, I said plastic — though they may be almost any synthetic, since this is a 1911 rifle) now has a steel ball for a pull. It looks odd but it works. And the front sight is a thing of beauty. A man has taken the time to hand-make a target globe front sight with replaceable inserts. I got only the one insert that’s in the sight now, which is two brass wires arranged like scope reticles. They look crude up close; but last week at the range I put four cast lead bullets in one inch at 100 yards, and that was the first time I ever loaded for this rifle.

Someone converted this Swiss Schmidt-Rubin model 1911 rifle into a target rifle. The stock is fashioned from the original military stock.

He replaced the conventional red synthetic bolt knobs with a steel ball, which he welded to the bolt handle.

The amount of time and care that someone put into making this target sight is amazing! This is where enthusiasts will take the sport when they have the time, motivation and skills. read more

Sam Yang Dragon Claw .50 caliber big bore air rifle: Part 4

by B.B. Pelletier

Part 1
Part 2
Part 3

The Dragon Claw from Sam Yang is a .50-caliber big bore air rifle.

This is the second accuracy test with Sam Yang’s Big Bore .50-caliber Dragon Claw single-shot air rifle. As you may recall, or you can check out by reading Part 3 again, the rifle shot all over the place last time. I decided that I was not seating the bullets into the rifling as far as they needed to be, so this time I took special pains to seat all the bullets. I’ll tell you how that went as I report my findings.

Air use
I’m still filling the rifle from the same Air Venturi 88-cubic foot carbon fiber tank that I was using when I started this report. The tank has not been refilled, and there are now about 150 shots on the Dragon Claw (at the very least!), as well as a couple fillings for a Talon SS reservoir. The gun is still being filled to 3,000 psi, so that carbon fiber tank is definitely the way to go.

A customer test
While I was testing the rifle, a Pyramyd Air customer needed some help getting his Dragon Claw filled, so I spent some time working with him. He sent me a picture of a target he shot with his rifle at 30 yards. I’d like to show it to you to use as a basis for comparison with the results I’m reporting today.

A customer sent me this 30-yard group from his Dragon Claw. It corresponds with what I’m seeing with the test rifle.

This customer also reports that the discharge sound wasn’t as loud as he’d thought it would be, and the recoil wasn’t as great as expected. He felt it was just a gentle push. I would agree with that observation. It isn’t until you get into the 500+ foot-pound region that these rifles really start kicking, and even then, they’re more like a .243 than a .30-06. read more

Sam Yang Dragon Claw .50 caliber big bore air rifle: Part 3

by B.B. Pelletier

Part 1
Part 2

The Dragon Claw from Sam Yang is a .50 caliber big bore air rifle.

Today, we’ll look at the accuracy of Sam Yang’s Big Bore .50-caliber Dragon Claw single-shot air rifle. Thanks for being so patient on this report. It took three separate trips to the range to collect the data for what I’ll tell you today, and the report will not end here. This rifle has some more secrets to reveal, although I now know a lot more about it than when I started.

Break-in helps
For starters, this airgun needs some break-in time, so plan on it. When I started this test, the rifle was very stiff and hard to cock, but now it has smoothed up considerably. The hammer spring is still very stout, so cocking the rifle isn’t that easy; but at least the hammer comes back smoothly now. In the beginning, it was actually difficult to stop the cocking mechanism at low power because the hammer required such a yank to retract. Well, that’s behind us now; and the rifle can easily be cocked for low power or high power. Plan on about a hundred shots for a break-in.

Open sights could not adjust for the barrel droop
I never planned on using this rifle with open sights since it has such a nice scope base on top of the receiver, but just for fun I tried shooting several groups with the open sights during the initial chronograph testing. Naturally, all testing was done at the rifle range due to the incredible power of the airgun, so the targets were at the same 50 yards I would normally shoot using a scope.

But even with the rear sight adjusted as high as it will go the rifle still shot about 6 inches too low at 50 yards. I tabled the report on open sights and moved on to a scope.

The second time at the range, I discovered that the adjustable scope mount was not adjusted for the amount of droop this particular rifle has, so that was another day I couldn’t really test the rifle. I did discover, however, that .495-inch round balls scatter all over the place. They shoot about two feet low and group in 12 inches or more, so I decided not to test them further. Both the Air Venturi 200-grain round nose lead bullets and the 225-grain Air Venturi round nose lead bullets from Pyramyd Air seemed to hold some promise, and they were the ones I brought back for testing the next time.

Scope and mount
I was using an AirForce 4-16x50AO scope mounted in an old B-Square (American-made) one-piece AA adjustable scope mount. You can’t get that mount anymore, but you can use a Beeman 5039 adjustable mount in its place.

Before the test
Going into the accuracy test, I had a couple notions that proved to be wrong. Maybe not entirely wrong, but certainly not completely right, either. The first that was the rifle was going to be more accurate on low power than it would be on high power, and the second was that the 200-grain bullet would outshoot the 225-grain bullet. I will address these faulty ideas at the end of this report.

How the test was conducted
I learned (I thought) during the chronograph test that the rifle had enough air for two good shots on high power and five good shots on low power. The assumption for low power proved correct, but during the testing I discovered that a third shot on high power was possible with reasonable accuracy. I say “reasonable” because of another variable that I’ll have to conduct another test to resolve.

The five-shot groups you see that were shot on low power were all shot with a single fill, but the five-shot groups on high power were shot using two fills. The rifle was refilled after the third shot.

Let’s see the targets!
The groups are too large to show actual size, so they’ve all been reduced to fit the screen. The target is a 50-foot timed and rapid-fire pistol target whose bullseye includes a 9, 10 and X ring and is 3-1/16-inch or 7.9cm in diameter. I will explain each target in the caption.

Five 200-grain bullets at 50 yards on low power are all over the place. This group measures about seven inches between centers.

Five 200-grain bullets on high power only look better by comparison with the others. this group measures about 4-7/8″ between centers.

The five 225-grain bullets shot on high power are scattered just like the 200-grainers on low power. This group measures about seven inches between centers.

Five 225-grain bullets shot at low power almost did well. Three are in an acceptable group of about one inch. The other two open it up to about 4.25 inches. read more

Sam Yang Dragon Claw .50 caliber big bore air rifle: Part 2

by B.B. Pelletier

Part 1

The Dragon Claw from Sam Yang is a .50 caliber big bore air rifle.

Today, I’ll test the velocity of the Sam Yang Big Bore .50 caliber Dragon Claw single-shot air rifle. For this test, I used two Air Venturi bullets and a swaged round ball that are available from Pyramyd Air.

The rifle is supplied with a probe-type quick-disconnect fill device, and I can finally report that the Koreans have now conformed with the rest of the world in supplying these adapters with standard threads that attach to common 1/8″ BSP fittings. In the past it was a chore matching these adapters to hoses you might have on hand (if you’re already into PCP airguns).

The No. 1 recommendation I have if you’re buying the Dragon Claw as your first PCP is that you also purchase the Pyramyd Air Quick-Disconnect male fitting and switch out the fill port on your rifle. Then, you can fill from a variety of high-pressure air devices, including the Air Venturi 88 cu ft carbon fiber tank. You’re going to want something that large to keep this monster gun supplied with air.

Let me address the air issue right now. This rifle does use a lot of air. I found that I got four useable shots on high power or eight shots on low power, and each time I did that the gun dropped from 3,000 psi to 1,500 psi for high power and 1,200 psi for low power. This number of shots per fill is fairly good considering the caliber of the rifle, but you’re going to refill it often. Don’t even think of using a hand pump for this rifle!

Shot with open sights
I decided to shoot the velocity test shots with open sights to simplify things at the range, and in so doing I learned that this rifle shoots very low at 50 yards. So low, in fact, that it was impossible to move the point of impact up to the point of aim. That’s good to know, because I’ll want to use a scope mount with some droop correction for the accuracy test.

While I chronographed the Dragon Claw, I also got to see how it shot with open sights.

The rifle actually grouped pretty well with open sights, considering I was shooting three different projectiles at two different power levels for each. Of the approximately 25 shots I fired, about 21 grouped in a hand-sized group. Unfortunately, it was below the target paper, so I’ll leave all accuracy testing to Part 3. But this test did show me a couple things about the gun.

I know why there’s a low-power level
First, you may remember that I was skeptical about using the low-power level. Now I know why it’s useful. With the

Air Venturi 200-grain round nose lead bullet read more