Diana 34 Easy Modular System (EMS) Synthetic: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Diana 34 EMS
Diana 34 EMS with synthetic stock.

Part 1
Part 2
Part 3

This report covers:

  • Scope
  • The test
  • Pellets
  • Sight-in
  • JSB Exact Heavy domes
  • Crosman Premier Heavy
  • Trigger
  • Heavy pellets
  • H&N Baracuda with 4.50mm head
  • Evaluation so far
  • Summary

Okay. Today is the test many have been waiting for — the Diana 34 EMS at 25 yards. How accurate is it?

Scope

I scoped the rifle with an older  UTG AccuShot 4-16X50AO scope, mounted in BKL 2-piece double-strap one-inch rings. Since the scope was already shimmed in the rings I figured they would adjust to the point of aim relatively easily.

The test

I shot from 25 yards with the artillery hold and my off hand rested on a sandbag. I will note that with the thumbhole stock I’m testing a true artillery hold isn’t possible, but I held the rifle as loosely as possible. My off hand was at the rear of the cocking slot.

I shot 10-shot groups today. I have to say the EMS is easy to cock and you don’t have to slap the muzzle to break it open. This is a very well-behaved air rifle.

Pellets

I selected JSB Exact Heavy domes from the test at 10 meters. In that test we learned that the 34 EMS likes heavier pellets that are also larger. So I also selected two heavier pellets that I hadn’t tried before. When you see the results I think you’ll agree I picked two good ones.

Sight-in

I shot a single JSB Heavy pellet at 12 feet and confirmed that the scope was close enough on for me to back up to 25 yards. Once there it took me three more shots to get on target. Of course I didn’t want to hit the center of the bull and destroy my aim point, so all groups will be at the edge of the black.

JSB Exact Heavy domes

First up was the sight-in pellet. The first shot landed in the top of the bull and I thought it was perfect, but the next several landed high and outside. When all 10 had been shot I had a somewhat vertical group that measures 0.675-inches between centers. It’s a little larger than I would like from this rifle, but there were no shots that were called pulls.

Diana EMS JSB Heavy
The Diana 34 EMS put 10 JSB Exact Heavy pellets into 0.675-inches at 25 yards.

Crosman Premier heavy

The second pellet I tried was the 10.5-grain Crosman Premier heavy. These pellets are sometimes the best of all, and today was one of those days. The 34 EMS put 10 of them into a tight 0.619-inches at 25 yards. 

Diana EMS Premier heavy
Crosman Premier heavys wanted to stay together when shot from the Diana 34 EMS. Ten went into 0.619-inches at 25 yards.

Trigger

You may recall that the 34 EMS has a different trigger that is not crisp like the Diana T05 or T06. This trigger has a second stage through which the trigger blade moves considerably. It’s light enough, but not crisp. I have said that it feels like a single-stage trigger, once you get to stage two. I got used to it in Part 3 and today I was able to do good work with it. I still can’t tell when the rifle is about to fire, but pulling the trigger has no adverse effect on the stability of the crosshairs.

Heavy pellets

I think there is something to this thing about heavy pellets and the EMS. It seems to like them a lot. If you get one of these, try it with heavy pellets first.

H&N Baracuda with 4.50mm head

The third pellet I tested was the H&N Baracuda with a 4.50mm head. I just knew this one was going to shoot well and it did. Ten of them went into 0.634-inches at 10 meters.

Dioana EMS Baracuda
The Diana 34 EMS put 10 H&N Baracudas with 4.50mm heads into a 0.634-inch group at 25 yards.

Evaluation so far

I really like the Diana 34 EMS. It is different than the Diana 34 of the past that we knew, but it is a worthy air rifle in it’s own right. Yes, Diana shouldn’t have touted the barrel shimming and caliber swaps before they worked out the details, but that marketing blunder has no bearing on the rifle’s excellence.

I don’t often select spring rifles to shoot at 50 yards, but I’m choosing this one. With luck I’m thinking we could see ten pellets in less than one inch.

Summary

If you have been waiting to see whether the Diana 34 EMS was a worthy air rifle, I think that point has been proved. I would recommend getting the wooden stock just so you can shoot with the full artillery hold, but if money is an object this synthetic thumbhole stock can also shoot. Today demonstrates that.

I just hope Diana makes the gas pistons, barrel shims and different caliber barrels available soon. I would sure like to try them out!


Does seating pellets extremely deep help?

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • The rifles
  • The test
  • El Gamo David
  • Discussion David
  • Diana model 35
  • Discussion Diana 35
  • Diana 27
  • Discussion Diana 27
  • Summary

Recently a reader posted a comment that he had improved his accuracy by seating pellets extremely deep into the barrel of his airgun. He said he pushed them in 40mm or more. So today I conducted a test to see what affect, if any, that has on a couple of my rifles.

The rifles

I selected the El Gamo David because we just saw it shoot. And I selected the Diana 35, which is a very accurate breakbarrel I last tested June of 2019. Then I researched both rifles and selected the best pellet from all my testing and also the best hold for each airgun.

The test

I shot off a rest at 10 meters. I shot 5-shot groups so I wouldn’t tire out in the middle of the test, but also so I could concentrate on my technique.

To seat the pellet deep I used an Allen wrench with 40 mm marked off on the shaft. I pushed the pellet into the bore until that mark was flush with the entrance to the breech. The reader who commented said there wasn’t any magic about 40 mm, it was just his way of telling us about how deep they were seated. And 40 mm works out to 1.5745-inches, in case you wonder.

40mm
The Allen wrench seated the pellets to about 40 mm deep.

El Gamo David

The El Gamo David shot best with RWS Meisterkugeln Rifle pellets. In Part four I put 5 of them into 0.166-inches between centers at 10 meters, resting the rifle directly on the sandbag. I shot the David first the way I did in Part 4 — seating each pellet with a ballpoint pen. The first shot hit the target to the right of the bull, but I continued to shoot the group anyway. Five pellets landed in a group that measures 0.607-inches between centers. It’s much larger than the group I shot in Part 4, so I will keep an eye on my shooting technique.

David Meister Rifle pen
When the pellet was seated with a ballpoint pen, the El Gamo David put 5 RWS Meisterkugeln Rifle pellets in 0.607-inches at 10 meters.

I was surprised that the group was as large as it was, given what the David did just last week, but maybe the group was more of an indication how well I was shooting — not the rifle.

Now it was time to seat the pellet deep. I started each pellet with the pen to get the skirt into the barrel, then pushed it in with the Allen wrench to the mark on the shaft. Then I shot each pellet just as carefully as before. This time five Meisterkugeln Rifle pellets went into as group that measures 0.648-inches between centers at 10 meters. It’s not much different and certainly no better than the first one.

David Meister Rifle 40mm
When the Meisterkugeln Rifle pellet was seated 40mm deep in the bore five of them went into 0.648-inches at 10 meters. This group is also a little more to the right than the last one.

Discussion David

So the El Gamo David didn’t do much different with the deep seating. Given the extra work that’s involved, I think this procedure is not for this air rifle.

Diana model 35

Next to be tested was the .177-caliber Diana model 35. This rifle delivered remarkable accuracy when I last tested it in June of 2019. It likes Air Arms Falcons the best of all and back then it gave 10-meter 5-shot groups that ranged from 0.194-inches to 0.371-inches between centers.

I first tested it with the pellet seated flush and using the artillery hold with my off hand at the rear of the cocking slot. Five Falcons went into 0.25-inches at ten meters. Not only is that a great group, it also proves that old BB can still shoot. And, it is in the range of this rifle’s accuracy with the same pellet a year and a half ago.

David Falcon flush
The Diana 35 put 5 Falcon pellets in 0.25-inch group at 10 meters when seated flush.

Next I used the Allen wrench to deep-seat the Falcons 40 mm into the bore. This time, using the same artillery hold the Diana 35 put five Falcons into a 0.836-inch group at 10 meters. This time the difference between seating flush and extra deep is decisive!

Diana Falcon 40mm
When seated 40mm deep, the Diana 35 threw the Falcon pellets into this 0.836-inch group at 10 meters.

Discussion Diana 35

I was so glad to see that I was shooting okay. This is why it’s nice to have an air rifle that always delivers. Also — never sell an accurate airgun!

At this point in the test I had one result that was inconclusive and one that was decisively against seating 40mm deep. So I shot one more rifle.

Diana 27

This rifle is my Hy Score 807/Diana 27 in .22 caliber. I used obsolete Eley Wasp 5.6mm pellets for the test. First I shot five Wasps that were seated flush with the breech. They made a group that measured 0.555-inches between centers at 10 meters. They also struck the pellet trap noticeably louder!

Diana 27 Wasp flush
The Diana 27 put 5 Wasp pellets that were seated flush into a 0.555-inch group.

Now for 40mm deep-seated pellets. This time the Diana 27 put five Wasps in 1.207-inches at 10 meters — a definite degradation in accuracy!

Diana 27 Wasp 40mm
When seated 40mm deep the Diana 27 scattered five Wasps into 1.207-inches at 10 meters.

Discussion Diana 27

These three little tests are not conclusive, but they do indicate that seating a pellet 40mm deep in the barrel doesn’t help — at least not with these three rifles. It was such a bizarre idea that I just had to know for sure. If the reader who told us about this would like to write a guest blog and expand on what I have done here, he is certainly welcome.

Summary

When the idea of seating 40mm deep was first mentioned I didn’t like it because of the lack of cushioning the piston would get. However I did listen closely during this test and couldn’t detect any difference in the shot cycle.

At least we gave it a try!


El Gamo David breakbarrel air rifle: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

El Gamo David
The El Gamo David is a lower-powered breakbarrel from the 1960s or’ 70s.

Part 1

History of airguns

This report covers:

  • H&N Finale Match Heavy
  • Breech seal
  • Pick it out
  • Seal is out
  • What to do?
  • Cocking effort
  • Summary

Today we look at the El Gamo David breakbarrel rifle’s velocity. In Part One I predicted that, if the powerplant is in good shape, the David should be able to push an 8-grain pellet out at between 550 and 600 f.p.s. I have not chronographed a single shot yet, so I will find this out as you do. Let’s get right to it.

H&N Finale Match Heavy

The first pellet I tested was the 8.18-grain H&N Finale Match Heavy wadcutter. The tin says they weigh 8.18 grains. I weighed five and got this:

8.2 grains
8.3
8.3
8.1
8.1

Then I shot a string of 10. Before the string started I shot 2 pellets to “wake up” the powerplant. Then I shot the string and 10 pellets averaged 480 f.p.s. The low was 464 and the high was 487, so the spread was 23 f.p.s. That’s not a terrible spread for a springer, but I would always like to see it smaller. At the average velocity this pellet generated 4.2 foot-pounds. I had expected more like 5.5 foot-pounds.

That string was slower than I expected. But the powerplant sounded okay. What is the first thing you should look at when you discover that a breakbarrel is off its feed? I’d like to turn this into a quiz, but we really don’t have the time, so I’ll tell you. The first thing you look at is the breech seal. Let’s look now.

David breech seal
The David’s breech seal isn’t looking so good.

Breech seal

Everything you see that’s round in the photo above is the breech seal. It may look like an o-ring but it’s not.

Take a look at the picture. The David breech seal is not an o-ring. It’s much larger. That tipped me off that Gamo had used a formed proprietary breech seal. For the prospect of fixing the rifle quickly, that’s not good.

Pick it out

I used a dental pick to start the breech seal coming out. That puts holes in the material and even tears out chunks, so this side of the seal cannot be reused. It took about ten minutes to get the seal out far enough that its size could be seen. I had hoped to possibly substitute a Weihrauch breech seal, but once I saw the size of the David seal I knew that idea was out. The David seal is huge!

By the way, both ends of my dental pick were severely bent in the process of picking out the seal. The good news is the bent ends will break off and I will have a different sort of pick when they do.

David breech seal coming out
It probably looks like the seal is ready to come out at this point. Not so! It took another 10 minutes of careful work with a small pocketknife blade to get it out.

Quick fix

Once the seal was out I confirmed that nothing I had on hand would replace it easily. I can think of many ways to repair the gun quickly at this point. Fitting a wood or metal spacer in the deep breech seal hole and topping it off with an o-ring seems possible. The spacer would resemble the original seal in size, but would be shorter so the o-ring that sat on top would seal the breech.

Or find a piece of rubber tubing that’s close to the same diameter as the breech seal, but a little smaller. Wrap it with Teflon tape to bring it to size. Cut it shorter than the breech seal so an o-ring can sit on top.

Or cut several leather washers and stack them in the hole. Either top them off with an o-ring or make them so high that they squash and become the breech seal themselves.

David breech seal out
Once the David’s seal was out I could see the size. It’s huge! More like a section of thick tubing cut to length. We are looking at the bottom in this photo, showing that the seal cannot be reversed. It’s not smooth enough.

The breech seal hole is very deep. I measured it as 0.372-inches from top to bottom. 

David breech seal hole
That seal hole is deep — 0.372-inches to the bottom!
It needs to be cleaned.

What to do?

What to do next is another pop quiz question. If you’re a lover of these old-timey airguns you know what to do. Get on the T.W. Chambers website and look under El Gamo. Only there is no listing for EL Gamo. Okay, just Gamo then. There is a listing for that, but no David model is shown. But what do we know?

First, we know that the El Gamo Expo was popular around the same time as the David and it lasted a lot longer. We know that from comments left by readers Lain and GunFun1 to Part 1 of this report.

Second, we know that the Expo was roughly equivalent to the David — or at least we believe it was. We believe that the David was for a limited market and the Expo was for a broader market and most likely replaced the David when it came out.

Third we know that in manufacturing a company will always attempt to make one part work for many different models. That is especially true of parts that share a common purpose — like breech seals. If you have gone to the trouble of creating the tooling and fabrication processes for a proprietary seal, you want to do it as few times as possible.

That only makes sense, as each unique part not only needs to be manufactured, it also needs to be managed. The fewer unique parts you have to manage, the better. You can buy 100 o-rings for a dollar and call them breech seals or you can spend the time and labor making 100 unique seals. The fewer unique parts that are in your product, the easier it is to make — though the performance will be at the mercy of the generic part you select and you will also have to ensure a longtime supply of the generic part.

The drawing of the Expo shows a breech seal that’s shaped like this one. It’s worth a try!

I GUESSED that the breech seal for the Gamo Expo that TW Chambers does have in stock will also fit the David. The price was 5.25 British pounds, plus shipping. By the time it arrives in about two weeks I will have about $15 invested. If I’m wrong about the fit, I can explore the other less desirable options.

Cocking effort

Well, I can’t shoot the rifle without a breech seal, so the velocity test has to be suspended. But I can test the cocking effort.

The David cocks with 15 pounds of effort. That makes it good for kids.

Summary

That’s where we find ourselves with the David. We are waiting on parts and we have a baseline on where the rifle was with the breech seal that was in it.

This is the downside of working on older air rifles. Sometimes they need attention. That’s just as much a part of the story of the El Gamo David as any of the other testing will be. As anyone who fools with vintage airguns will tell you — this is the fun part!


What do you want?: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • So what?
  • The most important thing
  • What gives accuracy — the barrel
  • What gives accuracy — the trigger
  • Safety
  • What gives accuracy — the breech lock
  • Powerplant
  • Sights
  • My idea
  • Between the lines

This is the start of a series that I think will be quite different. The inspiration comes from the SpaceX company that has now successfully put two astronauts on the International Space Station. SpaceX has significantly reduced the cost to build rockets and launch payloads, making space exploration more affordable. Elon Musk determined that he could buy the materials to build a rocket for just three percent of what the Russians wanted for theirs. That was what put him in business.

So what?

What does any of that have to do with airguns? Everything, I think. Because it illustrates just how much can be accomplished when there is a plan and when the schedule is not artificial but is based on realistic forecasts. This report is not meant to criticize any company or person, but it will also not permit the hardening of attitudes that stifles progress.

We are going to design an ideal airgun. In fact we are going to design a couple of them, and I am starting with the spring-piston powerplant. This will be an air rifle

If we are successful, we will design an air rifle that can be manufactured at low cost and yet have all the things shooters desire. I will start the conversation, but you readers are as much a part of this as I am. So — speak up!

The most important thing

I think the most important thing about an airgun is that it hits what it’s shot at. Power alone is not important because power without accuracy is meaningless. Beauty isn’t of chief importance because, while it might satisfy the taste, if it can’t hit the target it won’t get shot. Ergonomics aren’t that important because it can fit like a glove — if it doesn’t also hit the target it’s not going to be picked up. Price is not the primary importance because if it can’t be relied upon to hit the target, who cares how cheap it is?

Nobody made me full ruler and controller of anything, so if you disagree with me on this point, make your case. I’m not saying that power, beauty ergonomics and price don’t matter; I’m saying they only matter once there is an accurate airgun to apply them to.

What gives accuracy — the barrel

Accuracy is not just the barrel, but it certainly begins there. Crosman has learned that if they first ream the inside of the barrel tube before they rifle it, they get the best results. Sig has learned that the barrel doesn’t have to be choked — as long as the bore size is relatively uniform from breech to muzzle. Add that to what Crosman has learned and we know what must be done to rifle an accurate barrel. AirForce has learned that by cutting a progressive leade into the rifling at the breech, pellets will load straighter and deform less when shot. Add that to what Crosman and Sig have learned and we start to see the beginnings of good barrels.

FX has learned that it is possible to swage in the “rifling” from the outside of the barrel and lower the cost to make a barrel. But, they also know that a barrel rifled this way will be very picky about what pellets it likes. The barrel will be very accurate with a certain pellet within a certain range of initial velocities, but that range must be maintained. Oops! Perhaps we have gone too far.

I could go on and talk about lapping the barrel after rifling. Bartlein laps before rifling and again, after rifling. Their barrels are considered some of the finest in the world. But for our project, I think lapping after rifling is one step too far. It takes a $100 barrel and makes it a $250 barrel rather quickly. If the reaming process is run slow enough and the tools are kept sharp enough to prevent chattering, I think we have gone as far as we need to.

What gives accuracy — the trigger

An accurate air rifle needs a good consistent trigger to realize its maximum potential. But it doesn’t have to be a 50-gram trigger from a 10-meter rifle. I have told you of the benefits of the ball bearing trigger that certain vintage Dianas have. They were great for their day, but that day has passed and those triggers contain far too many parts to be economically acceptable. We also know that Rekord triggers have been superb for nearly 70 years, and the Air Arms version is the highest evolution of that design in production. Ivan Hancock used to make and sell a brass version of the same trigger that was called the Mach II, and that handmade version was perhaps as good as the design ever got.

But we don’t need a trigger that good in our ideal air rifle. Let’s turn our attention to Sig, instead, and look at their  Matchlite trigger that’s in the ASP20 breakbarrel rifle.

Sig ASP20 trigger graphic
Sig Matchlite trigger. Graphic provided by Sig.

Sig produces an American-designed airgun trigger that’s ideal for our project rifle. Ideal, only we can’t use it unless Sig also builds the rifle. What it demonstrates is that the Rekord is not the only good airgun trigger design. The Matchlite cannot be adjusted as light as the Rekord, but within the box of its performance it’s good enough for the rifle we are building.

Sig ASP20 trigger box
The adjustments on Sig’s Matchlite trigger work inside the bounds of safety. You get a light trigger that the lawyers are okay with.

What we need is a trigger with the adjustability of the Matchlite but with simplified design. It needs to have fewer parts and should retain some adjustability. And it should have a positive trigger stop.

Safety

Yes, there should be a safety. It should be ambidextrous and manual. 

Design the breech so one hand has to pull down on the muzzle of the barrel to fully access the breech for loading. That’s your anti-beartrap. You just made the shooter part of the safety equation.

What gives accuracy — the breech lock

Sig also showed us that a breech lock can be built that locks up a breakbarrel like a bank vault without an overly aggressive detent. Their Keystone breech is light-years better than any other one on the market. But is that the only way to do it? I think not. I think with some thought a different type of lockup can be created that doesn’t infringe on the Sig patent — unless Sig decides to built the rifle I’m talking about!

Spring-gun manufacturers other than Sig haven’t been investing any thought in how to lock a breakbarrel breech or how best to reduce friction in the pivot joint without allowing the base block to wobble when the barrel is closed. Through corporate hardening of the attitudes they have put progressively heavier detent springs and more aggressive chisel detents into the hinge joints. I can think of a system right now that would lock a breech solidly and be nothing like the Sig Keystone. And I am not an engineer!

Powerplant

The powerplant is where this project really takes off. In the recent report on the Beeman R10 you learned that the piston stroke is where power lives — not the diameter of the piston. Now, stay with me on this.

Why do people love the FWB 124? After the accuracy, the one big reason for liking the 124 is how easily it cocks, relative to the power. So, let’s do this — let’s reduce the piston diameter to around 20mm, and let’s increase the stroke to around 90mm. Let’s reduce the power of the mainspring to a third of what it is now to create a breakbarrel that cocks with 15 lbs. of effort, yet puts out 12-13 foot-pounds in .177. Can it be done? I’m not sure, but it would be something to strive for.

The Vortek PG3 tuning kit suggests what kind of powerplant parts are needed to do what I’m suggesting. Knowing that up front means designing a powerplant from the beginning that meets the specification for light cocking, reasonable power and vibrationless operation. Button the piston during the design stage and make the buttons easily replaceable (they literally fall out when the piston is out of the spring tube!). Or, take a page from the TX200 book and put a rotating nylon ring front and rear on the piston with no possible spring tube contact of the piston body in-between.

What if the piston wasn’t made entirely of steel? What if the body was nylon with a steel head? The loss of weight would combine with the lighter mainspring and tighter powerplant tolerances to eliminate vibration.

What a powerplant like this gives us is a rifle that doesn’t weigh a lot. That’s why I say it should be a breakbarrel — to keep the weight off. I’d like the rifle to weigh no more than 6 lbs. And lighter is better. That means a synthetic stock. I want a stock with a 14-inch pull, a sculpted pistol grip with a palm swell that fits both right and left-handed shooters equally well. It should have a very slim forearm that’s not too deep. We save weight plus get a rifle that feels right instead of a fencepost! Fill the butt of that stock with sound and vibration-damping compound, or cross-braces that create the feeling of a solid butt without the weight.

Sights

I have spent a lot of time discussing good open sights with you, and several readers have taken up the crusade. Ditch the fiberoptics, or at least make them either optional or an included part that doesn’t have to be installed. The basic front sight should be a square post that is sized to match a square notch in the rear. But — make the sights removable so options can be installed by the owner.

Sure — give them a Picatinny scope base on the spring tube — BUT — make it a screw-on option!

The rear sight should be easily and positively adjustable for both windage and elevation. There are plenty of good rear sights on the market today, so this should present no challenge.

My idea

There — that’s my idea for a new spring-piston air rifle that I believe would be very popular. It’s nothing like what you are ever likely to see, but if each feature/component were done right, and that means as close to what I said as possible, I think the world would have a new icon to celebrate.

But who says I know what everyone likes? Well, I sort of got it right with the Discovery, didn’t I? I missed on the Rogue, but what Crosman brought out under that name bore no resemblance to what I briefed them on. I was in the hospital while that one was being put together. And the Bronco was reasonably successful. At least people liked it once they shot it. 

Between the lines

If you know the airgun industry you can read between the lines of today’s report. Some companies are in better position to execute such a new spring gun than others. But the sad thing is when the ammo trucks arrive at the battle a half hour too late for resupply. Let those who know understand!

Now, you readers take it from there. Or tell me why I’m wrong and what needs to be done, instead.


Diana 23: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Diana 23
Diana 23.

Part 1
Part 2

A history of airguns

This report covers:

  • The test
  • RWS Hobby
  • Sights are off
  • H&N Finale Match Light
  • RWS R10 Match Pistol
  • RWS Superpoints
  • H&N Match Green
  • Discussion
  • Summary
  • One last thing

Today we look at the accuracy of Diana 23. I sure hope she’s accurate!

It took me half an hour to set up the range indoors, so I wanted to make this count.

The test

I shot the rifle from a sandbag rest at 10 meters. I used the artillery hold and did not test anything else. I rested the rifle on my off hand that was back almost touching the triggerguard. The stock is a little short to allow me to treat it like other adult rifles, so my off hand placement was the best I could do. I shot differing numbers of pellets at each target so I’ll address that when we get to it.

RWS Hobby

First up was the RWS Hobby pellet. Given that this is a Diana rifle I felt RWS pellets had the best chance to be good. Since the Hobby is a wadcutter and it landed at 10 o’clock just outside the bull on the left I saw the first shot clearly without a spotting scope. But I didn’t see shot number two. And when shot three enlarged the first hole ever-so-slightly, I felt that Hobbys were a good choice.  I decided to shoot ten of these.

After 10 shots I had a nice little group just outside the bull. It measures 0.574-inches between centers and is what I would call a keeper.

I have to tell you that the pictures that follow are poor because I wasn’t able to lug out my heavy camera tripod that I normally use. I had to use a flash and hold the camera by hand. None of that is good for these kinds of pictures.

Hobby group
The Diana 23 put 10 RWS Hobbys in 0.574-inches at 10 meters.

Sights are off

I know what you are thinking after seeing that group. The sights need to be adjusted to the right. But the 23 sights don’t have a windage adjustment. They do have dovetails, both front and rear, and it is possible to push either or both sights to make small left or right corrections. But when I examined the front sight I saw that someone had moved it already — and to the right, which is in the wrong direction for what I needed with this pellet. You move the front sight in the direction opposite of how you want the pellet to move.

Seeing that I thought I should leave the sights alone, because somebody went to the trouble to put them where they are. They may be right for a certain different pellet and with luck I might find it.

Diana 23 front sight
This top-down photo of the front sight shows that someone has drifted it to the right. You can even see the metal distortion on the left side of the sight base where it was hit with a hammer.

H&N Finale Match Light

The next pellet I tested was the H&N Finale Match Light wadcutter. The first shot hit at 10 o’clock even farther to the left than the Hobbys. When the second shot hit even farther away and opened this group more than the entire first group of Hobbys, I decided to only shoot 5 shots. They made a very horizontal group that measures 0.795-inches between centers.

With open sights a vertical group often means you can’t see the front sight very well. A horizontal group means either the breech joint is loose or you are just shooting a bad pellet for that rifle. The breech joint on this 23 is fine.

Finale Match Light group
Five pellets gave me a very horizontal group that measures 0.795-inches between centers. 

RWS R10 Match Pistol

Next I tried 5 RWS R10 Match Pistol pellets. I thought they should do well in a Diana, and they did. Five went into 0.509-inches at 10 meters. However, given that the Hobby group is not much larger and was shot with 10 pellets, I don’t think the R10s are any better.

R10 Match Pistol group
The Diana 23 put 5 RWS R10 Match Pistol pellets into a 0.509-inch group at 10 meters.

The R10 is a great pellet for the 23, but it’s costly. Hobbys do just as well so I will stick with them.

RWS Superpoints

How about a non-wadcutter pellet, BB? The 23 is not a 10-meter target rifle, after all. Once again I turned to RWS, whose relationship with Diana has always made the two a good match.

I shot 5 Superpoint pellets and, while the group was larger than the Hobbys or the R10s, it was dead-center! See? That’s what I was looking for. So I went ahead and finished the group with 5 more shots. What I got was not a small group, but it is exactly where we want it to be and it just looks right to me.

Ten RWS Superpoints went into 1.162-inches at 10 meters. If you just go by the numbers it’s a horrible group, but when you look at it, it doesn’t seem so bad.

Superpoint group
Ten RWS Superpoints went into a 1.162-inch group. The number sounds bad, but the group is right where I want it to be. I think it’s good for a plinker.

H&N Match Green

The last pellet I tested is the pure-tin H&N Match Green wadcutter. But on the second shot I could see they weren’t going to group, so I only shot 5 pellets. Five made a 1.349-inch group that was the largest group of the test.

Match Green group
Five H&N Match Green pellets went everywhere! Group measures 1.349-inches.

Discussion

This test brings us to a point that needs discussing. If, after more testing, we find that the Superpoints still hit in the center of the target, but the Hobbys group tighter, do we leave the sights alone and shoot Superpoints or move the sights and shoot Hobbys? I would probably stay with the S-points, but you guys talk amongst yourselves.

Summary

Well, I’m quite happy with this little air rifle. It’s small, has a nice trigger and the power is probably where it should be. For once I bought something that didn’t need to be tuned. I didn’t tell you but I paid $75 for this gem, plus something for shipping. I see them offered all the time at $175 and higher and I think that’s a little high. But at this price I couldn’t pass it up.

One last thing

I’m looking for some oddball airguns to write historical reports on. I would like to purchase these airguns, so at present I’m not looking for loaners. Here is a list of the airguns I am looking for.

  • A Rutten Windstar or any Rutten spring rifle that has the double cocking underlever technology.
  • A Park HR91 or HR93.
  • A Benjamin Rogue.
  • An Erma ELG10.
  • A Walther LP II pistol.

I may want to look inside some of these airguns, so I don’t want loaners. I want to own what I get so I can do with it whatever I want. If you or anyone you know has any of these airguns for sale please contact me at [email protected]


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.

Dioana 23 with 27
When compared to the Diana 27 (bottom) the Diana 23 looks tiny.

Diana 23 Germany
This is the only other marking on the rifle. There’s no date of manufacture.

The rifle

The Diana 23 I am reviewing is in .177 caliber and has a rifled barrel. They also came in .22 caliber and in both calibers smoothbore barrels do exist.

The rifle I’m testing is 36 inches long and has a 14.25-inch rifled barrel. The pull is 13 inches exactly. The rifle weighs 3 lbs. 11 oz. which puts it solidly in the youth air rifle class. Yet as diminutive as it is, I find that older men are attracted to it far more than kids. My late friend Mac had several of them and loved them dearly, including a .22 that absolutely fascinated him. He thought of them as the model trains of the airgun world — sort of like I feel about the Sharpshooter pistol that’s powered by rubber bands.

There are two different models of Diana 23s. One was produced from about 1927 to 1940 and the other one was made from 1951 to 1983. The gun I am looking at is the later model.

Two versions of the later rifle

The 1951 to 1983 model 23 also breaks down to two different versions. The first one has a thinner slab wood beech stock with finger grooves on the forearm. That is the one we are looking at. The later version has thicker wood, no finger grooves, pressed checkering a slightly raised cheekpiece and different front and rear sights that may be plastic. I have the earlier version, but unfortunately I do not know when the model switch was made.

I think the model I have is the most desirable because it is slim and lightweight. It makes no pretence of being anything more than a basic air rifle.

Trigger

The trigger is two-stage and not adjustable. It is a direct sear that holds the piston in place until the moment of release, yet the trigger pull is very satisfactory.

Breech seal and locking detent

The Diana 23 breech differs from the larger vintage Diana rifles that start with the model 25. Instead of the breech seal being around the rear of the barrel, it is a leather seal attached to the end of the spring tube around the air transfer port. The rear of the barrel is solid metal that presses against the seal when the barrel is closed.

Diana 23 breech seal
You are looking down into the air transfer port behind the barrel. The leather seal is around it rather than around the breech. The silver bump on the left is where the ball-bearing breech lock engages.

Diana 23 breech
The actual breech has no seal. Don’t be fooled by the discoloration. Diana used the same ball-bearing detent from their larger rifles to lock the breech closed during firing.

Sights

The front sight is a tapered post. The rear sight is a V-notch at the end of a leaf. A sliding elevator works on a stepped ramp to raise and lower the notch. As simple as it appears, you get crisp detents as the elevator slides up and down the ramp and there is even tiny pointers on both sides of the elevator to tell you where you are. So, as inexpensive as this model is, Diana still put a lot of thought into it.

Diana 23 rear sight
The rear sight is simple yet effective.

Cocking

The mainspring is weak, so cocking a Diana 23 is very easy. I am guessing it will register under 10 lbs. when I test it in Part 2.

I looked through the cocking slot of the stock and saw that the mainspring was very dry, so I took the barreled action out of the stock and oiled the mainspring with some bicycle chain oil. This rifle doesn’t buzz when fired which is good because as weak as it is, this would not be the mainspring to put anything thick on.

Diana 23 spring
The mainspring was dry, and in this view some of the coils appear to have collapsed.

With the action out of the stock I used the opportunity to go over all the metal parts with Ballistol and to look for a date of manufacture. No other marks were seen anywhere — including on the inside of the stock.

What is it good for?

You might ask what a weak little pellet rifle like this is good for. I would turn that around and ask you how well your 6-year-old granddaughter does with the Beeman R7 you bought for her? The Diana 23 belongs to a class of diminutive pellet rifles that have no modern equivalents. 

I like the R7 as well as anyone, but it isn’t made for wee teeny folk like this Diana 23 is. There is an entire class of small air rifle that isn’t being made anymore. Even rifles like the Ruger Explorer that come close are still larger, heavier and harder to cock.

Summary

This will be a quick look at an air rifle most of you will never own. There are others like this one that I will never get to, so enjoy this look while you can.


Diana 27S: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Diana 27S
Diana 27S.

Part 1
Part 2
Part 3

A history of airguns

This report covers:

  • Trepidation
  • Disassembly
  • Anti-beartrap mechanism
  • Pictures!
  • Secret washer
  • Remove the trigger?
  • The rest of the disassembly
  • Cleaning
  • Lubrication and assembly
  • Hit the wall
  • Frustration
  • The solution
  • The final solution
  • Denny was a pattern maker
  • The irony!
  • One more thing
  • Summary

Today I do something different. I show you a tuneup that is not complete. I do that because the monster has been vanquished and I will be able to get the Diana 27S back together to report on the performance after a cleaning and a lube tune. Here we go.

Trepidation

When I began this job a week ago I had trepidation because of the anti-beartrap mechanism Diana put in this model. I have stripped other springers with anti-beartraps before and I’ve always been successful, but their presence complicates the rest of the powerplant quite a bit — especially the trigger.

I also knew that the 27S probably had the trigger from the Diana 35 instead of the trigger that’s found in the 27. They are similar, except the 35 trigger has a more powerful spring pushing the inner ball bearing cage. And that particular spring also has a guide rod that the 27 spring does not have. 

So, I took a lot of pictures as I worked. It turned out those pictures saved the day, though not in the way you might think. Explanations are coming.

Disassembly

First the stock is removed to get to the barreled action. Since the 27S has an articulated cocking link it has an additional stock screw on the bottom of the forearm. I was prepared to see that screwed into a steel bridge that the link passes through — to keep it from buckling. But there was no bridge. The screw just has a rounded end for the link to slide on and the absence of a mark on the link told me it had never touched that screw. The stock keeps the link from buckling!

Diana 27S stock screw
That screw under the forearm was supposed to screw into a steel bridge that the cocking link passed through. But it didn’t.

Diana 27S  stock screw inside
The forearm stock screw attaches to this threaded bushing inside the wooden forearm. The tip is rounded to allow the cocking link to slide over it, but the link never touched it! The wood of the stock keeps the link aligned.

Diana 27S  stock screw detail
The end of the forearm stock screw is rounded to allow the cocking link to slide over it freely, but the link has not touched it yet.

Anti-beartrap mechanism

Setting the stock aside, I now examined the anti-beartrap mechanism.

Diana 27S  anti-beartrap
This picture shows the long sliding plate of the anti-beartrap mechanism. Two springs pull it into the trigger when the cocking link moves far enough to permit it.

Diana 27S  anti-beartrap 2
This is the anti-beartrap mechanism interfacing with the trigger assembly. The two springs pull the sliding plate into the trigger when a notch in the trigger blade permits it to enter.

At this point I thought I was home free. This mechanism is simple and looks straightforward. But I was about to encounter a problem!

Pictures!

Because this is the first time I have seen this mechanism, I took a great many pictures of it. And they saved the day several times. The large bolt in the center of things is where the forward triggerguard screw attaches. It also limits the movement of all the anti-beartrap parts to a short range of movement that you will see in a moment. But that wasn’t the most important thing. I will get to that in a bit.

Diana 27S  anti-beartrap 3
The bolt in the center of the anti-beartrap (arrow) limits the movement of the rest of the parts.

Secret washer

Here is the first surprise this mechanism gave me. After I disassembled it completely a small thin washer remained on the spring tube. Where it came from I had no idea, but when I reviewed all my pictures of the mechanism, taken while disassembling it, I found it! It took me quite a while (45 minutes of trying the parts various ways and then searching through the photos) to determine where this small washer belongs.

Diana 27S  anti-beartrap washer
The arrow points to the small thin washer in the anti-beartrap mechanism that I found after disassembly. Only a portion shows, but it’s enough to determine which layer the washer sits in.

Diana 27S anti-beartrap washer out
There is the tiny thin washer, hiding under the trigger blade. Apparently it is shy. Next to the trigger are the crosspin and the stout trigger spring that gave me so much trouble!

Remove the trigger?

At this point in the disassembly I decided to disassemble the trigger assembly from the spring tube. I believed that was necessary, though I now know different. It meant I also had to remove the anti-beartrap mechanism — also unnecessary. But I did it. At least you get to see the parts that are in the mechanism.

Diana 27S  trigger mechanism
The trigger mechanism with the anti-beartrap still connected. This picture was very helpful later, as well.

Diana 27S  anti-beartrap apart
The bolt has been removed, giving access to all the parts. I have also disconnected both anti-beartrap springs.

I don’t show all the beartrap parts apart, but they are basically several sliding plates of steel that can be seen stacked in the picture of the assembled trigger above that was taken before disassembly.

The rest of the disassembly

Now the barreled action went into the mainspring compressor for complete disassembly. With the beartrap apart and the trigger out of the rifle the two side pins that restrain the internal trigger parts (the black and silver cages and the ball bearings that are in the black cage) can be removed. Just press in on the black trigger cage with the compressor to take tension off the two pins and they fall right out. Then back off the compressor and the mainspring relaxes. You can then remove the spring guide and the mainspring.

At this point all other spring rifles require removal of the barrel to disconnect the cocking link from the piston. Then the piston can be removed. I did remove the barrel, and only later discovered that the two-piece articulated cocking link would allow me to remove the piston without first removing the barrel. However, taking the barrel off allowed me to lubricate the pivot bolt and the to pivot washers with moly grease, so the effort was not wasted. But this was another difference the Diana 27S showed me.

Cleaning

I cleaned all the parts with denatured alcohol. To get inside the spring tube I used a long dowel with paper towel wrapped around the end. The inside of the spring tube was surprisingly clean and did not appear to have ever been taken apart. I will let reader Carel address that, since the gun was his before I received it.

The other parts were also very clean for the 40 or so years this airgun has been around. The mainspring is not perfectly straight, but it’s close enough that I don’t think a replacement is needed. 

Lubrication and assembly

I lubed the leather piston seal and the front and rear of the piston body, as well as the central piston rod, with moly paste grease. Then I lubed the mainspring with a light coating of Tune In A Tube grease. I also used TIAT to stick the three ball bearings inside the black cage for assembly. Even when the cage fell to the concrete floor the balls remained tightly inside. Now for assembly.

Hit the wall

And assembly was where I hit the wall. To this point in the report I had spent perhaps 90 minutes on a job that usually takes me 30. I was taking my time to understand the anti-beartrap mechanism completely. And I missed the biggest challenge of all — the trigger spring!

Frustration

I took the remainder of that day and two hours into the next day trying to put the crosspin and the trigger spring back in the rifle! I could get it partway, but never all the way in. I started with brute force and when I didn’t have enough of that I used wood clamps. Let me show you what challenged me so much.

Diana 27S  spring tube
This is where the trigger assembly goes. That small bump (arrow) holds one end of the trigger spring in place. As you can see, it is coated with TIAT to hold the spring.

Diana 27S  spring standing
The trigger spring is standing up on the small bump. It’s held by TIAT. The trigger assembly has to come down and connect to the other end of the spring.

Diana 27S  trigger interior
The underside of the trigger assembly has another bump (arrow) that has to fit inside the trigger spring on its other side.

You might think that keeping the powerful trigger spring in place was a problem. But it wasn’t! Tune In A Tube is so tacky that it held the spring through all I did. The problem was pressing the trigger assembly down far enough so the crosspin could pass through both side and hold it. That was what I struggled with for the rest of the time.

The solution

The solution was in two parts. First I had to find a way to use the small wood clamps to press the trigger assembly down against the force of the spring and still not slip off the greasy spring tube and trigger assembly. I am now estimating that spring has 60-80 pounds of force. It’s way out of proportion with its size!

I played with clamping positions for hours, almost getting it before the clamp shot off and I had to start over. Then the lightbulb went off and I put the clamp where it could not slip, no matter what. It still slipped but now it was slipping because the force of the spring was bending and twisting its jaws. That made it easier for me to control.

It was now Day Three of my saga, but I knew I was going to succeed this time. It only took me 10 minutes and a few tries before I succeeded in getting the crosspin 3/4 on the way through.

Diana 27 crosspin almost
The crosspin (arrow) is almost through the trigger assembly and the two anchor points on the spring tube.

The final solution

The second part of the solution was to ask my neighbor, Denny to tap the crosspin through the trigger assembly while I held it in place with a more powerful wood clamp. I had read somewhere that many hands make light work or men should learn to ask for help or something like that!

Anyway, I showed Denny what I was trying to do and then he tapped the pin though as I held the trigger assembly down and in line with the wood clamp. It worked the first time in less than ten seconds.

Denny was a pattern maker

Then Denny looked at the job and told me I probably needed to get a Kant Twist clamp for tight work like this. You see — Denny was a pattern maker. That’s a guy who makes jigs, fixtures and patterns for production work. He worked last in the aviation industry, making patterns for the B2 bomber.

I looked Kant Twist clamps up at Granger and saw a wide variety of cantilever clamps. They are indeed the tools needed for a job like this. Better still — DON’T TAKE THE TRIGGER OUT IN THE FIRST PLACE!

So why did I take the trigger out? Because I thought I had to! The 27S trigger is very similar to the trigger that’s in the Diana 35 — with one important difference. The Diana 35 trigger pin passes through the spring tube of the rifle, where the 27S trigger pin is below the tube. Let’s see.

Diana 35 trigger pin
The crosspin that holds the Diana 35 trigger assembly passes through the spring tube (yellow arrow) as well and has to be removed to get the piston out. The blue arrow points to another powerful trigger spring in the 35 trigger that was somehow easier to work with last year than this 27S spring has been.

Diana 27S crosspin
As you can see, the Diana 27S trigger crosspin (arrows) hangs below the spring tube. That allows the piston to come out without the trigger being removed. And, unless my eyes deceive me, the wire in this spring is thicker than the wire in the 35 trigger spring.

The irony!

The irony of this misadventure is this — Diana designed the 27S to be easily maintained. The trigger doesn’t have to come out to remove the piston, nor does the anti-beartrap need to be removed. Even the barrel can be left on the gun! I didn’t know any of that up front so I did all of it and increased my work a lot. Of course I did get to examine, clean and lube all the parts, which is what you want to do in a tune, so I would have done most of it anyway. But I wouldn’t have removed the trigger! 

This report is now a detailed set of instructions for the next brave soul to follow. That’s why I have taken the time to spell out all the details.

One more thing

When I disassembled the rifle I noticed that the trigger in the 27S resembles the Diana 35 trigger in many respects. The spring that pushes the black cage holding the three ball bearings is very strong, just like the one in the 35 trigger. It’s not like the regular Diana 27 trigger that’s weaker. The 35 cage spring has a short steel spring guide, while the 27 trigger does not. This 27S did not seem to have that guide when I disassembled the rifle, or if it was there I never saw it and it has now gone to the same place as all my missing socks.

The truth is, I found a photo that shows conclusively that there was no spring guide in that spring to begin with. I tried to assemble the action without that guide, but that powerful cage spring just bunched up. When I removed it, it was kinked. I don’t want to assemble the rifle wrong, so I ordered a new spring and guide from T.W. Chambers and will wait for them to arrive to complete this job. I don’t want to do this job again, so it’s worth doing it right this time!

Diana 27S cage spring
There is no steel spring guide in the black cage spring in the Diana 27. It’s end would be in front of the end of the spring. Look at the same part in the Diana 35 above. Photo was taken before disassembly.

Summary

This has been a bit of a horror story of what can happen when you disassemble a spring-piston air rifle. This is perhaps the second time in the last 25 years that I have been so challenged — which is my way of telling you it usually isn’t like this. Please don’t be put off by this tale, but glean what you can from what I did and how it turned out.

Oh, and guys — please be open to asking someone to help you when you need a third hand. I mean — honestly! Pride goeth before a fall!