Slavia 618 breakbarrel air rifle: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

Slavia 618
Slavia 618.

History of airguns

This report covers:

  • History
  • Research
  • Model variations
  • What is the Slavia 618?
  • Comparisons
  • Stock
  • Summary

Some of you may have been hoping for Part 2 of the Beeman R10 rifle report today. Well, Part 2 will be the strip-down and installation of the Vortek tuning kit, and I need a couple days to do the work and take the pictures, as well as the writing. So today I’m starting my report on the Slavia 618 breakbarrel pellet rifle.

History

Guess what? Almost nobody knows the history of this air rifle. It has a lot of fans, but nobody seems to know much about it.

The Blue Book of Airguns says it was made in the 1970s — period. But they say the same thing about the Slavia 622. Well, I received one of those as a gift in about 1961 or ’62, so that’s obviously not right.

My rifle from the early 1960s was labeled PIC, for Precise Imports Company. They were one of the U.S. importers of Slavia airguns. Considering when I got mine I believe the 618 and 622 had to have been made in the 1950s. The 1970s as an ending date I don’t dispute.

No doubt there is someone who lives close to the Czech Republic that was formerly Czechoslovakia where the arsenal that made the air rifle is located. It was made at Ceska zbrojovka in Brno. I apologize for not having the correct diacritical glyphs on the cyrillic letters in the names.

Research

I researched a lot of expired auctions to gather any information I could find on this model. I see that around 2010 these air rifles were bringing $20-35. Today most hover at the $75-100 range, with shipping raising that even higher.

Model variations

I bought one 618 off Ebay that was supposed to be in good working order. It is, except the rear sight is bent to one side from what looks like a fall. I was going to leave it alone and just test the rifle, but then a second one popped up for less money. This one was advertised as complete but needing seals. That was also an accurate description, though it needs a little more than just seals. It feels like it is gunked up inside and at least needs a good cleaning. We’ll know more when I open it up.

I will say that the both the wood and metal finishes are poor on both my rifles. The shellac is apparently not long-lasting and the metal rusts easily. Many of the 618s look like this.

I can test the first rifle for velocity, at least. I’m expecting it to be in the low 300s with lightweight pellets. I found velocities from 312 f.p.s. for a tired one shooting Crosman Premier Light pellets to 390 for the same rifle after a rebuild.

What is the Slavia 618?

The Slavia 618 is a small youth-sized breakbarrel air rifle. Several weeks ago when I tested the Diana 23, a similar youth-sized air rifle, a couple readers mentioned how much they enjoy their 618s. That’s why I got these two rifles to test, study and rebuild. I have been hearing about the 618 from readers for many years and decided it was time I investigated for myself. Side-by-side the Diana 23 and the Slavia 618 are very similar. The Diana is a little longer overall, at 35-7/8-inches versus 35-1/4-inches for the 618.

As far as I can tell, the 618 only came in .177 caliber. It was the 622 that was a .22 (only). One reference mentioned that some 618s were rifled and others were not, but I can’t really prove that. Both of mine appear to be rifled.

One of my 618s weighs 3 lbs. 6 oz. Because of the wood stock and one other difference I will tell you about, there will be small weight differences, but all 618s are lightweight.

When I looked at both my rifles I discovered several difference between them. These are differences that would come over a longer production cycle, which is why I think the Blue Book dates of the 1970s fall short. I am assuming that over time the design of a product will be changed to make it less costly to produce. With that assumption in mind, I have labeled one of my rifles as older than the other. Let me explain why.

Comparisons

The rifle I’m calling older has a thicker barrel. It measures 0.502-inches or 12.75mm in diameter at the muzzle. The newer rifle measures 0.468-inches or 11.89mm at the same place. The front sight on the older rifle is a blade sitting in a dovetail. The front sight on the newer rifle is a plain round pin. Since dovetails are more difficult to cut, I think that first one has to be older.

Slavia 618 nuzzles
The muzzle on the right is on what I am calling the older rifle. It’s larger than the muzzle on the left.

Slavia 618 older sight
The front sight on the older rifle is a raised post that’s dovetailed into the barrel.

Slavia 618 newer sight
The front sight on the newer rifle is just a plain round post.

The rear sights on both rifles appear identical, but the sight on the older rifle is spot-welded in two places to the dovetail that slots into the barrel and on the newer rifle it’s welded to the dovetail in just one place. The sight with the single weld is also the one that’s bent, and, looking down from the top it appears the weld may have weakened when it allowed the bend. I plan to try to tap it back straight, but I won’t be surprised if that weld shears off in the process. That sight leaf is also bent upward, so some of the elevation adjustment has been lost.

Slavia 618 bent sight
The rear sight on the newer rifle has a single weld and has been bent to the left.

Slavia 618 straight sight
The older rifle rear sight is straight and has two welds.

Both of my rifles have a leather breech seal, which leads me to believe they both have leather piston seals, as well. In my research I discovered that the 618 also came with an o-ring breech seal and a synthetic piston seal. I bought a synthetic breech and piston seal while awaiting the arrival of both rifles, but now I don’t know that it can be used in either one. Fortunately leather seals should be easy to fabricate.

I also bought two new mainsprings that both rifles probably need. We will see when we open them up.

Neither of my two rifles have a serial number. Some 618s do and others don’t On the 618s that have them, the serial number is stamped into the flat left side of the base block that holds the barrel. I saw serial numbers as high as 150,000+ when I researched the rifle. The serial number may have been required for certain countries to import the rifle, or CZ may have started putting numbers on all its air rifles at some point. Either way it does suggest, along with the leather seals, that my two rifles are older examples.

I saw one other interesting thing in my research. Many of the 618s I saw had two screws at the pivot joint. One was the pivot bolt and the other was a locking screw on the main bolt’s periphery. Both of my rifles have just a single pivot bolt. The other side of the bolt screws into a threaded nut that has two spanner holes for anchoring it when disassembling the rifle.

Slavia 618 two base blocks
As you can see, there is no serial number on either base block. And the pivot bolts have no locking screw. The rear sight on the upper rifle is bent up.

Both my rifles have the model name, number and country of origin stamped into the top rear of the spring tube. These markings run perpendicular to the axis of the spring tube. There are other 618s that have the same markings running along the spring tube’s axis, and in several places I found references to that variation being older.

Slavia 618 writing
Both my rifles have writing that’s perpendicular to the axis of the spring tube.

Both spring tubes on my rifles are plain, but I did find a 618 on the internet that had a short set of grooves at the rear of the tube. They were less than two inches long. The person doing the review thought they were there for mounting a scope but I’m pretty sure they are there for a peep sight.

The compression chamber is made by swaging a solid steel block into the end of a hollow steel tube. The transfer port has been drilled through this block, so once it’s held in by the swages, a spring tube is born.

Stock

All the 618s I found, including the two I own, have a one-piece beechwood stock with finger grooves on both sides of the forearm. I did see one 618 with a custom-made walnut stock and of course our own reader, Vana, made a stock for his 618 out of firewood that he described in a 6-part report.

The buttstock has fine ridges over the central half of the wooden buttplate. The pull is 13-1/2-inches.

Summary

What we have with these two Slavia 618s is the potential for a lot of fun. You readers seem to have created another fan!


Umarex Air Javelin airbow: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Umarex Air Javelin
The Air Javelin from Umarex.

Part 1

This report covers:

  • However
  • The “barrel”
  • Not a toy!
  • Sights
  • Front sight
  • Rear sight
  • Adjust the stock
  • Install the cocking handle
  • Charging
  • One fact to bear in mind
  • Summary

At least one of you readers is really interested in the Umarex Air Javelin, just as I am, so today is Part 2. However, because this is an arrow launcher, this Part 2 will be a little different. I normally test velocity in Part 2, but the Air Javelin is better tested outdoors for that and today the temperature here in sunny Texas is 36 degrees, F. Yes, we have bright sunshine and the temp is supposed to rise to 62 late this afternoon, but my testing and photography work gets done in the morning, so the cold is hampering me.

However

That doesn’t mean I can’t shoot the Air Javelin (hereafter called the AJ) indoors. In fact, by shooting it indoors I will get a really good idea of how loud the report is. Remember that I could not hear it when I shot it at Industry Day at the Range in January. I’m making this report up as we go, so let’s get going!

The “barrel”

Several readers were inventing new universes for the AJ to inhabit. Like, what if a pellet could also be loaded into the hollow air tube the arrow fits over? Let’s look at that now.

Air Javelin barrel
This is the hollow air tube the arrow fits over. The CO2 gas comes up that tube to propel the arrow.

The gas tube/barrel is permanently attached at its base to the source of CO2 gas. Of course it is not really permanent, but it cannot conveniently be removed to insert a pellet — even if it was the right size inside. While such a feature is possible and even has been done by other manufacturers — nobody on the planet right now other than Umarex is offering an arrow shooter like the AJ for only $169.99.

Not a toy!

The AJ comes with a hang tag on the triggerguard that tells you it is not a toy. Believe it! I just hope that new airgunners won’t look at the arrow velocities that are displayed on the box at just over 300 f.p.s. and think, no big deal. Because a 170-grain arrow traveling at that velocity can do serious damage to tissue, and can kill! I said in Part 1 that you could take a deer with the AJ if you keep the distance reasonable, and the under 60-yard distance that I stated is about where most bow hunters take deer. There are powerful crossbows that can reach out farther and I’m sure a skilled longbow shooter can also do it, but hunters should always try to take their shot as close as possible — and that goes for airgun and firearm hunters as well. Let’s give the AJ the respect it deserves.

Sights

The AJ comes with what firearms shooters call back-up iron sights, or BUIS for short. They are not really metallic; that’s just a name they are given. You readers know that BB likes shooting with non-optical sights, so I will test them first. Before testing with them, they must first be mounted.

Front sight

The front sight attaches via an Allen screw that’s screwed down onto the Picatinny rail. First you slide the front sight onto the rail, which is easy, because the fixed sight dovetail is larger than the dovetail on the Picatinny rail.

Air Javelin front sight
The front sight attaches with an Allen screw.

Air Javelin front sight bottom
This is the underside of the front sight. On the right you can see the end of the Allen screw that presses against the Picatinny rail.

Air Javelin front rail
This is the front of the Picatinny rail where the front sight slips on the gun.

When the locking screw makes contact with the rail it pushes the dovetails on the bottom of the sight up to jam against the rail. It’s straightforward except for one detail. The screw has to make contact with the rail to do its job. Remember that a Picatinny rail has deep 5mm-wide slots spaced at regular intervals to hold accessories. The end of the Allen screw needs to press against one of the risers between the slots and not fall into a slot!

Air Javelin front sight on
Here you see the front sight on the airgun. The Allen screw that is in the rear of the sight is aligned with and pressing against the first riser on the Picatinny rail. Note that the rear of the sight is slightly elevated. Positioning it like this aligns the front of the sight with the front of the rail.

Rear sight

The rear sight attaches to the Picatinny rail and not to the long flat spot at the rear of the rail. The screw that tightens the movable jaw at the bottom of the rear sight base is also the crossbar that interlocks with a slot in the Picatinny rail.

Air Javelin rear sight underside
Here you see the cross screw that is under the rear sight. It draws the movable jaw tight and it also bears against a ridge in the Picatinny rail to keep the sight from moving.

The sight will not attach to the long flat spot at the rear of the rail because that cross screw gets in the way. But it will attach to the first slot in the rail, and since this is a peep sight we want it as close to our sighting eye as possible. So the last slot is where it goes.

Air Javelin rear sight mounted
The rear sight is mounted with the cross screw passing through the first slot in the rail. This is as far back as the sight will go. The sight is tightened to the rail by that large knurled knob.

Adjust the stock

Once the rear sight is mounted you can adjust the stock. I told you in Part 1 that there are 5 stops in the stock, but this time I pulled the rear part of the stock off and saw there are actually 6 holes for locking it. The last hole for adjusting the stock as long as possible is very hard to feel when the pin clicks in. 

I found that I needed the stock set in the first click back to see through the rear peep sight correctly. The length of pull is set at 14 inches on the nose. My sighting eye only sees a faint outline of the peep hole this way.

Air Javelin peep
The peep hole is sized just right, from what I can tell so far.

Looking through the peep, the front sight looks huge! I can see that my traditional target-type sight picture will be no good. This sight screams center of mass. It’s like a non-optical dot sight — and a big one, at that!

Air Javelin front fiber
The orange fiberoptic up front looks as large as the side of a barn! I will have to abandon my target-type sight picture and shoot for the center of mass with this one!

Install the cocking handle

The AJ is ambidextrous. The cocking handle will go on either side of the rifle. For this feature Umarex gets the Golden BB award for innovation! Remember — this is a $170 arrow launcher! How easy it would have been for the designers to figure they had already given buyers enough, just by the low price. Many companies would do that, but Umarex saw a way to add functionality cheaply and they did! Go back to my, “What makes an airgun ‘good’?” report, because this is a shining example! This is how it is done.

I held the AJ to my shoulder and pantomimed operating it to decide that I wanted the cocking handle on the right side. It’s slightly easier for me to cock that way and, since I have to take the gun down from my shoulder to load an arrow anyway, it isn’t an inconvenience. If this was a pellet rifle, I might have chosen the other side.

Air Javelin bolt right
On the right side of the AJ receiver you see the bolt with the screw hole for the cocking knob half-hidden by the receiver. It’s on the right side of the long cocking slot.

Air Javelin bolt left
Here is the view of the bolt from the left side of the receiver. Again the screw hole is half-hidden.

I used a ballpoint pen in the hole on the left side of the receiver to pull the bolt back so I could attach the handle on the right side. The spring tension is light and this is easy to do. Then screw the cocking handle all the way in. It has a shoulder that prevents the large handle from contacting the side of the cocking hole.

Air Javelin bolt top
This top-down view shows what the cocking handle looks like when it’s attached.

Charging

I spent a lot of time today showing you the setup. The manual covers all the same areas, but the instructions fall short of the things I have shown and discussed. Now it’s time to charge the airgun with an 88-gram CO2 cartridge (which you all know can also be a 90-gram cartridge).

Start with an uncocked gun. The forearm is unlocked by a square pushbutton on the right side of the receiver. Then slide the forearm forward for clearance. I would put 5 drops of Crosman Pellgunoil into the place where the cartridge screws in every time I install a new cartridge.

Air Javelin cartridge
Slide the forearm forward and screw the CO2 cartridge into the AJ. I recommend Crosman Pellgunoil on every cartridge.

One fact to bear in mind

Once the CO2 cartridge is installed and pierced there is no way to remove it without exhausting all the gas. The manual says to not store the gun with a cartridge installed. I don’t think they mean overnight, but if you are putting the gun away for a time, remove the cartridge.

The manual also says there may be some hissing and loss of gas as the cartridge is being screwed in. I experienced that. Once the cartridge stops turning freely, get set to screw it in as far as you can with a single turn of the hand. Even then you might have to get a second grasp to complete the motion. The gas will stop abruptly when the cartridge is sealed.

Would a shutoff valve at this location be desirable? Certainly. How would they do it? Given the way the AJ is designed at present, it wouldn’t be easy. Bear in mind that the design of the gun is for slimness and convenient handling., I think I will take that over saving some of the gas. Remember, there will not be that many shots, even from this giant cartridge. 

Air Javelin 1077 AS
The Crosman 1077 AirSource had a valve to stop the flow of gas from the 88-gram CO2 cartridge. See how clunky it was!

Summary

I spent my morning setting up the AJ to shoot. She’s now got sights, a cocking handle and is charged with CO2. It’s 12:30 p.m. and it’s still just 54 degrees outside. Next week, cold or not, I will shoot it for you. Time for me upload, edit and schedule this report.

This report will go differently than others have, because of what I’m testing. But we will still get to know the Air Javelin as well as we possibly can.


What makes an airgun “good”?

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Soapbox!
  • Marauder
  • What makes an airgun good?
  • My list
  • Accuracy
  • A good trigger
  • Ease of cocking
  • Innovation
  • What doesn’t sell?
  • Price-point sales
  • Summary

Soapbox!

I’m on my soapbox today and I am preaching to the airgun industry, but probably also to some of you readers. I typed “what makes an airgun good?” into Google and came up with a list of retailers who all have lists of the “best” airguns of 2020. There were also some magazine articles with similar lists. I looked at all their lists. They had one thing in common. They were all bought and paid for! Every airgun on those lists was one that was either manufactured or at least sold under the name of a couple well-known manufacturers. Oh, they all had different-sounding product titles, but each of them was a subsidiary of a well-known airgun maker.

A couple of them were indeed airguns that have a long-standing basis of customer support, like the Daisy 880 and the Benjamin 392. The 392 is no longer produced, but it has been replaced by the 392S, which is a multi-pump in a synthetic stock. How similar it is to the now-discontinued 392 I will try to discover when I test it.

Marauder

The Benjamin Marauder made several lists, and it deserves to! This is a precharged pneumatic (PCP) that once lead the market and still offers features customers desire. A Marauder has a great trigger, quiet operation, good accuracy, a fine adjustable trigger, and the ability for the owner to fine-tune it to suit their preferences. 

The Marauder has also come out as a semiautomatic this year, but it’s not out yet and the jury is still out. I know the trigger is not as crisp as the one on the bolt-action Marauder, but whether that poses a problem remains to be seen. Accuracy and the other aspects of operation will have to be tested.

What makes an airgun good?

Marketing departments are confronted with putting a happy face on whatever products their company has to sell. Sales departments are tasked with closing the deals. And purchasing departments must buy products that can be sold. Who in the company is charged with knowing what makes an airgun good? Nobody, it seems.

Apparently knowing what make an airgun good is my job. Or, if not, I’m going to do it anyway, since nobody else seems to want to do it.

My list

The following are things I have observed that the market seems to appreciate and desire. If an airgun has them and if it truly delivers them the way the customer expects, the product has a good chance of doing well. That’s not as guarantee, just a good chance.  As I write about them I will tell you what works and what doesn’t.

At the end I will address price-point sales, but they should be kept separate from regular sales on the open market.

Accuracy

Real accuracy is very desirable. But what does it mean to be accurate? What it means is being able to put shot after shot into the same place or very close to the same place.

Is five shots in one inch at 25 yards accurate? It’s okay but it’s not really what customers look for these days. What about five shots in a half-inch. Well, that can be considered accurate, but it all depends on what kind of airgun is doing it. If it’s a spring-piston air rifle that costs less than $300, then, yes, it’s quite accurate. If it’s a PCP that costs $1,000, then no, it’s not very impressive. HOWEVER, if it is a Olympic-grade PCP target rifle that costs $3,200, it doesn’t matter!!! Nobody cares what a rifle like that does at 25 yards, because that kind of air rifle lives and dies at 10 meters or 11 yards. Learn the expectations of your products, buyers, before you start purchasing them.

A good trigger

A good trigger is one that has a crisp release that is uniform and predictable, time after time. The weight of the pull or let-off doesn’t matter nearly as much as people think. A service rifle National Match trigger on an AR-15 must have a release of not less than 4.5 pounds. That number looks high to many shooters, but it is the standard by which triggers of this category are tested. But don’t take my word for it. Listen to the company’s description of a highly-regarded $279.00 Geissele High-Speed National Match trigger.

“Our Service Rifle Trigger includes our exclusive 5-Coil trigger spring which will give a nominal 4 lbs. on first stage. The Service trigger pull weights are biased with most of the pull weight on the first stage. This will allow a light second stage with an icicle-sharp break, effectively giving your weapon a match-grade trigger let-off.”

So the key is the crisp let-off and not the pull weight. Sig Sauer knows that and delivers it in their new ASP Super Target. Weihrauch knew it years ago and incorporated it into their HW 40, which is the basis for the Beeman P3. Reader Kevin once tried the trigger on my Wilson Combat CQB 1911 pistol and guessed the let-off at one pound. It is actually three pounds. 

One final thing about triggers. If you make them adjustable make certain they really do adjust! Everyone who has tried the Sig ASP20 adjustable trigger has nothing but praise for it because it really does adjust. Same for the trigger on the Benjamin Marauder. However I have tested hundreds of triggers that say they are adjustable but nothing changes when you adjust them. Adjustable triggers are not supposed to be placebos or busy boxes, and shooters resent it when they are.

Ease of cocking

This isn’t the same as light cocking. The ASP20 once again wins in this category because it cocks easier than it should for the power it develops. I have tested several other gas spring air rifles recently that also cock much easier than their power output level would suggest. 

And don’t think this is limited to spring-piston airguns. A number of bolt-action PCPs are harder to cock than they should be and I have seen their owners protest loudly. There have been some “Mark II” models come to market just to correct this fault, so be wise and don’t let it happen to begin with.

Innovation

Customers may not say much about it, but when a company innovates, they know it. And they often vote with their wallets.  I have given suggestions for several innovations in the past year, and I hope some companies took them to heart.

Remember the $100 PCP project? What did it spawn? The Benjamin Maximus, that for a time was priced under $200. It’s $30 more these days, but it’s still one of the best bargains on the market.

How about the Seneca Aspen multi-pump that’s also a PCP? People have been asking for that for more than a decade and now we have it. Yes, I am aware that FX did it first with their Independence, but that rifle cost over $1,600 and was not targeted toward the market that wanted it.

Seneca Aspen
The Seneca Aspen is both a multi-pump and a PCP.

What doesn’t sell?

I’m not going to explain this list, because it’s too controversial. 

  • Fiberoptic sights
  • Camouflage coverings
  • Scopes bundled with airguns — unless the scopes are exceptional
  • Automatic safeties
  • Using the word “target” in a product title for something that is clearly not for shooting targets

Price-point sales

As some companies grow they look for other markets they deem lucrative. Discount and big box stores seem to attract a lot of attention. To sell to them there is but one criterion — price. The product must have the same general set of features that it has for the open market, but since price is the most important factor, anything that can be done to lower it is considered. For this market a product doesn’t have to perform to the same standards as one that’s sold to the open market. Brand loyalty and repeat business are not hallmarks of this trade. Price is king, along with a willingness to accept a higher level of returns.

This market is not less complex than the open market. It’s just different. Some companies sell the same products in both markets and in the price-point market they accept a lower margin that is partly offset by higher volume of sales. Some companies build products to lower specifications for this market and some companies remove things from their standard product offerings — like one magazine instead of two or a cheaper scope and rings bundled with the price-point sales.

Other companies never sell to the price-point market. They realize they cannot maintain the same standards and control of their products, so they never opt in.

To sell John Brown
What John Brown buys
You have to see the world 
Through John Brown’s eyes.

Summary

I wrote this report after seeing many lists of the “best airguns of 2020.” The lists were obviously artificial. Some of the guns on the lists have not yet come to the market. How can they be the best? After examining several of the lists it became clear they were generated through the process of an extended and hopefully concealed marketing campaign. That’s not the way good airguns are made. 


Rifling revolutionized!

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Outside the box
  • Rosenthal award
  • Rifling
  • How it works
  • Outside rifling?
  • Accuracy
  • Range increased by orders of magnitude!
  • Trouble brews
  • What is to come?
  • Rumors are flying!
  • Summary

Outside the box

I’m sure you have heard the phrase, “Think outside the box.” Many organizations don’t really want their people to do that. The organization just wants their employees to enlarge the box a little, but to continue to respect the time-honored principals that got the organization to where it is today.

Rosenthal award

But there are exceptions. In engineering there is an annual Sol Rosenthal Award for the creative idea that best advances its technology that year. Unlike many awards, there is only one caveat to this one. A prototype of the idea must be implemented, so it can be compared to an existing reality that can be measured.

The idea does not have to be an object. For instance, in 1978 a high school student in Twinsburg, Ohio, created a roundabout to replace a busy intersection in town that had a 4-way stop. The student demonstrated her idea on the stage of her school’s auditorium to the town council who was so impressed that they redirected $875,000 in highway repair funds to create an actual roundabout in town. The throughput of traffic at the selected intersection increased by 27 percent and accidents decreased by an astounding 31 percent — fatal accidents by 100 percent!

The result of this idea from a high school student is now the tens of thousands of roundabouts that have been installed or are under construction all around the United States. Fifteen-year-old Anita Carson won the 1978 Rosenthal Award of $250,000, and today Dr. Carson runs her own successful traffic analysis and management planning group in Fairfax, Virginia.

Rifling

In 2019 a graduate student at Stanford University in California, created a novel new type of rifling. Instead of a tube with lands and grooves inside, Thomas Manke made a rod that is rifled on the outside! He claimed there are numerous advantages to this form of rifling, the principal one being access to the lands and grooves. Manke says barrelmakers who use his process will have a much easier time both creating the rifling as well as perfecting it after it has been created.

Manke had to build a prototype to demonstrate his idea, so he used an airgun — a Benjamin Discovery that he modified. The idea is difficult to envision, so I will explain it now.

Benjamin Discovery
Manke’s modified Discovery. Photo provided by Thomas Manke.

How it works

A normal barrel develops pressure behind a projectile inside a tube. Since the pressure is too great for the projectile to resist, it pushes the projectile out of the barrel with force. Hundreds of years ago the inside of a barrel was smooth and only the straightness of the barrel directed the projectile to fly along a reasonably predictable path.

Some time after guns were first invented someone put grooves in the barrel with the thought of containing all the soot and ash from the burned gunpowder. At first the grooves were straight but then someone decided if they were cut in a spiral they would be longer and collect more residue. That didn’t work, but the spiral grooves did cause the projectile to spin, and its accuracy improved dramatically. The people who did all this are lost to history, despite what claims you may read, but the idea of rifling caught on and has advanced to its very high state today.

Outside rifling?

If the rifling is on the outside of a rod instead of inside a tube, how does the projectile get its push? Manke uses a larger and shorter tube on the outside rear of the rifled rod and his projectile fits inside that tube and around the rifled rod. Therefore, you may envision a Manke projectile as a disk. The outer edge seals the bore of the short hollow tube and the inner edge is engraved by the rifled rod. A Manke projectile is a flying disk!

Manke disk
The Manke disk is a donut-shape that fits around the rifled rod and inside the hollow tube.

The rifled rod doesn’t need to be very long. As long as it is about one inch past the end of the outer hollow tube, everything works as it should.

Manke system cross-section
The Manke system is simply a reverse of a conventional rifled barrel.

Testing the MD

Manke created his testbed rifle in 10 days by modifying a Benjamin Discovery. He said he used the Disco because it was the cheapest PCP he could find, but that almost any PCP can be modified to accept his disks. He also said there is no reason why spring-piston guns and CO2 guns cannot use his system with equal success.

Accuracy

Manke’s first test astounded even him. When the disk leaves the end of the rifled rod, air pressure causes it to tip and fly flat toward the target. It is spinning from the rifling, of course. He also discovered that he can alter the orientation of the flying disk by rotating the rifled rod, because apparently when the disk leaves the rod it orients according to its last contact.

After sighting in his testbed rifle Manke shot a 5-shot group at 25 meters that measures o.o-inches between centers. It was this group that was submitted with his patent application, as well as his doctoral dissertation and is shown here with special permission.

Manke bull
Manke’s first target was shot at 25 yards. Five disks were fired and there is no discernible separation of their impact points. The rifled rod was turned a precise amount for each shot. This is a 0.0-inch group. Photo provided by Thomas Manke and yes, the bull is upside-down.

Range increased by orders of magnitude!

Manke also discovered that his disks can be made to fly much farther than conventional bullets of similar weight. His 7.74 mm disks are made of lead and weigh 35 grains, but he says he can alter the weight within limits by changing the thickness of the disk. If they are fired perpendicular to gravity they act like Frisbees, flying as much at 20 times farther than a conventional bullet of the same weight and speed. If they are oriented vertical they have remarkable resistance to crosswind, though they do fall to earth just as fast as a conventional projectile.

Trouble brews

Manke did not develop his idea for the Rosenthal Award. It was the foundation of his doctoral dissertation. However, one of his faculty committee members withdrew after learning that an airgun was the basis for his proof. He said as he withdrew, “Mr. Manke has shown himself to be a very bright engineering student, but his involvement with firearms that shoot lead projectiles is not in good moral taste. Surely he must be aware that lead is known to the state of California to cause cancer and birth defects or other reproductive harm. And firearms are socially wrong from a moral standpoint.”

The dissenting faculty member was allowed to remove himself and was replaced by the head of the engineering department, who then submitted Manke’s idea to the Rosenthal Award committee.  He also announced that the Defense Advanced Research Projects Agency (DARPA) was offering Stanford an open-ended grant to investigate Manke’s thesis. Their stipulation was based on the university retaining Manke as the principal investigator. The university president responded that Dr. Manke would indeed be allowed to continue his research as a new tenured chair of the mechanical engineering department.

What is to come?

There is no doubt that Dr. Manke’s invention is going to have a major impact upon both firearms and airguns. In an interview given on Fox News Manke himself gave just a single example. What changes will result from a sniper weapon being able to fire with accuracy to 20 miles? DARPA has asked him not to speculate further, but Lieutenant General Robertson, the agency’s spokesperson, stated that this invention is as fundamental as the wheel. There will be no way to protect the patent, because anyone who tries it will get the same results. He said, “This is not nuclear science. This is fundamental physics that any child can replicate!”

Dr. Manke will be exploring many other aspects and problems of the disk. For example, it will be difficult, if not impossible, to get disks that weigh as much as bullets of the same caliber. That may have consequences that are both good and bad, and Dr. Manke wants to identify those consequences as soon as possible so exploration can begin.

Rumors are flying!

People who have heard about Manke’s discovery are talking! I can tell you that as far as I know there is no truth to the rumor that FX is considering calling their version of the outside rifling a Smooth Twist Three barrel.

Summary

Sometimes we go for a long time with not much advancement in the world of ballistics. And then something comes along that changes everything overnight. Dr. Thomas Manke’s discovery has opened a new door in the world of unguided ballistics.


IZH-61 repeating spring air rifle: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

IZH 61
The IZH 61 sidelever repeating air rifle.

Part 1
Part 2
Part 3

A history of airguns

This report covers:

  • The joke
  • Beeman peep
  • The test
  • Air Arms Falcons
  • H&N Finale Match Light
  • What was I doing wrong?
  • Can I shoot bad on demand?
  • Fatigue!
  • Proof of the pudding.
  • Stopped
  • Summary

Today I mount a peep sight on the IZH-61 I have been testing and shoot it for accuracy. I had originally planned to mount a dot sight, and I did, but the results were a disaster! Let me remind you of what happened. This is what I said after trying the dot sight.

————————————

I mounted the UTG Micro Reflex dot sight on the IZH-61 and prepared to shoot it at 10 meters, rested. I had to remove the front sight so the dot had a clear view of the target. The rear sight was just adjusted as low as it will go and was out of the way.

Oh, oh!

BB has slipped a cog everyone! He hasn’t even read the title of his own report!

BB is fine

No, BB hasn’t slipped a cog. He spent 90 minutes with the IZH-61 this morning, trying to shoot groups with a dot sight and failed to do so. His failure is your benefit, because he has some interesting information to share.

Parallax!

The IZH-61 I’m testing only has an 11mm dovetail at the very rear of the receiver. When I mounted the UTG Micro Reflex dot sight there it had a huge problem with parallax. Remember my report on the Romeo5 dot sight earlier this week? Some of you asked me what the advantages were and I said less parallax was one. Well, the UTG sight has a holographic screen and, when it’s mounted close to your eye, there is a lot of parallax. In all my testing of that sight on other airguns I have mounted it about 12 inches or more from my eye and the parallax was not noticeable, but this time the sight was three inches away and it was. The best I could do with RWS R10 Match Pistol pellets was 5 in about two inches. I’m not showing that group because it isn’t helpful.

Well, I gushed all over that Romeo5 sight from Sig. Why didn’t I mount it on the 61? I tried but the Romeo5 only mounts to a Picatinny base. Well, doesn’t UTG make an adaptor for converting those to 11mm dovetails? Yes, they do. And would you believe it — that adaptor will not fit the base of a Romeo5? It fits but the place Sig has put the Picatinny key in the base of the Romeo5 has the adaptor sticking halfway out the back.

Peep sight

I have a great idea! I’ll mount a peep sight on the rifle and try again. Why didn’t one of you readers suggest that? 😉

————————————————

The joke

The joke was that several readers had suggested mounting a peep and wise old BB ignored them, because BB marches to the beat of a different drummer. Or maybe it’s someone playing a washboard.

Beeman peep

I mounted a Beeman peep sight, which we learned the other day is really a Williams sight by a different name. I was able to adjust the rear sporting sight down out of the way, so it didn’t have to be removed from the rifle. And I learned a very important lesson today — one that I preached to all of you several days ago, but I had to re-learn it myself today.

peep sight
This peep goes on the rear of the receiver, and I made certain it was mounted tight. 

When I first sat down at the bench and tried to shoot with the peep sight I found the pull of the stock was adjusted too long. I couldn’t get my eye close enough to the peephole. Fortunately the IZH-61 has an adjustable butt that takes care of that. I didn’t catch it while sighting in because that was done offhand, where a longer pull is no problem.

The pistol grip also makes pulling the trigger with precision a problem. The grip is so small that it’s hard to use the tip of my trigger finger. So I used the first joint, and even that was a stretch!

The test

I shot the rifle from the bench. Given the AR-style stock it is next to impossible to use the artillery hold with the 61, so I held it as loosely as I could. I rested my off hand on a sandbag and the rifle on my hand.

I shot 5-shot groups in this test until the last target. The 5-shot magazine sort of promotes that. I used the same magazine that I have used for all previous tests.

Air Arms Falcons

In previous tests Air Arms Falcons have worked well, so I thought I would try them again today. I used them to sight in and also for the first group.

The first shot from 12 feet hit the target low and to the left. I adjusted the rear sight up and to the right. The peep I am using is the more expensive one that has knurled knobs for the adjustments instead of just screws. It’s easier to adjust, which I appreciate. Think about that when ordering a peep for yourself.

By the third shot the pellet was hitting the target right at the aim point. I knew when I backed up to 10 meters the pellet would climb up the paper, so I stopped at this point and went back to 10 meters. This is where I discovered that the butt was too long.

Shots 4 and five went into the same hole from 10 meters, so I felt the rifle was sighted in. I adjusted a few clicks to the right and shot a 5-shot group of Falcons. It was HORRIBLE! Five Falcons went into 1.345-inches at 10 meters. Not only that — they dropped lower than where I had them sighted. I will tell you right now that this rifle is much more accurate than that. I hadn’t yet discovered what I was doing wrong.

Falcon group
Five Falcon pellets went into 1.345-inches at 10 meters. I am sure the IZH-61 is more accurate than this!

H&N Finale Match Light

Next I tried five H&N Finale Match Light target pellets. They did well in earlier tests. But this time they let me down — sort of. The one thing I learned while shooting this group was what I was possibly doing wrong. That turned out to be a good thing, but we are not quite there yet.

Finale Light group
Five H&N Finale Match Light pellets went into this 1.679-inch group at 10 meters. Notice that the top four pellets are together in a much smaller 0.44-inch group. That stray lower pellet showed me what I was doing wrong.

What was I doing wrong?

The problem was simple to discover. I was not focusing on the front sight for every shot! I was focusing on it for some shots (like the top four in the last group) and on the target for others — like that stray hole at the bottom. Could it really be this simple? Heck, I am writing about peep sights and I know they work this way and even I (as great as I am) am having trouble staying focused! That gave me an idea for a little experiment.

Can I shoot bad at will?

If I was right about this I ought to be able to shoot a bad group by focusing on the wrong thing. I would take careful aim, but vary my focus between the front sight post and the target. If I am right, this should give me a poor group. I would shoot the best pellets I knew of, which for this rifle are RWS R10 Match Pistol pellets.

Five pellets went into a group that measures 1.172-inches between centers. It is the best group of the test thus far, but if I am right about the focus thing, I should be able to do better.

R10 Match Pistol group
When I shifted between focusing on the front sight and the target, the IZH-61 put five RWS R10 Match Pistol pellets into a 1.172-inch group at 10 meters. It is the smallest group of the test, but much larger than groups shot with the sporting sights that came on the rifle.

Now, if I am right in my thinking, I can shoot the same pellet into a much smaller 5-shot group, just by focusing on the front sight for each shot. There is probably some bias in this sort of test, but I have a way of reducing it.

The next 5 shots went into a group that measures 0.465-inches between centers at 10 meters. That is close to two-thirds smaller than the last group!

R10 Match Pistol group 2
Five R10 Match Pistol pellets went into 0.465-inches at 10 meters when I focused on the front sight post for every shot!

Fatigue!

Yes that group is much better, but oh, how tired I was from just those five shots! It was fatiguing to concentrate on that front sight so much. And that is why my first two groups are so large, I think. For some reason I find it very hard to concentrate on the front sight of this little rifle. That’s odd because with the Diana 27S last Friday I nailed the sights so well! But maybe the reason is in what I just said.

This “little” rifle is extremely short and the front sight is so close to my eye that it’s hard for me to see it clearly. It’s only about half as far away as a pistol sight when held at arm’s length.

Proof of the pudding.

Okay, I said I was going to prove that concentrating on the front sight is the answer. Now I will shoot a 10-shot group of R10s and concentrate on the sight for every one! I adjusted the sight 5 clicks to the right and proceeded to shoot the first clip, followed by a reload and then the second clip. That’s ten shots in all. I purposely did not look through the spotting scope while shooting this target, so I would not see anything that would break my concentration.

This time all 10 shots went into a group measuring 1.008-inches between centers. It looks better than the size indicates.

R10 Match Pistol group 3
That’s 10 RWS R10 Match Pistol pellets in 1.008-inches at 10 meters.

Stopped

I ended the test at this point because all the concentration had worn me out. The IZH-61 is reasonably accurate, but for me it takes way too much effort! And I want to make one more point. The 61 is the repeater and was never as accurate as the model 60 single shot, simply because the pellets had to be fed through the clip. Too much happens to the pellets for them to remain true.

Summary

I have gone as far as I intend to with the IZH-61. I have taken it from a new-old-stock rifle that had no clips and didn’t work properly because of hardened oil to a functional repeater that never misses a beat. At least it has been given a fair test.

For my money the TR-5 Pro target rifle that Air Venturi is bringing in is a better deal than searching for one of these. The one I tested for you out-shot this rifle.

This series began with a lot of hearsay quotes that I have heard over the years. It now ends with a clear picture of just how well the little rifle performs.


Range days at the 2020 SHOT Show

by Tom Gaylord

Writing as B.B. Pelletier

This report covers:

Sig Virtus

P365 BB pistol

Virtus airsoft

Smart Shooter

It’s over

Media day at the Range

Umarex USA

Air Javelin

Air Saber

Constant Acceleration Pneumatic Arms

Light gas

Not done yet

That’s all

I went to two range days this year. Sig Range Day was on Sunday and Industry Day at the Range was Monday. Both are for the media, so we get to see and possibly shoot the guns they are showing at SHOT. I say, “Possibly” because the guns don’t always cooperate. I have seen several that failed to function on range day. That’s either because they were rushed through production or sometimes it’s just bad luck.

Sig Range Day — Sig Virtus

The first day was all Sig. This year they had one new PCP pellet rifle that is now shipping — the semiautomatic Virtus. This rifle is based on previous designs of Sig CO2 repeaters and has a belt-fed magazine. This one is a precharged pneumatic (PCP) though, and develops up to 12 foot-pounds in .22 caliber. So it’s a fun gun!

I shot it with the Romeo5 dot sight and also with the flip up iron sights that are no-doubt called “Backup Iron Sights (BUIS)”. Well, the Romeo5 wasn’t cooperating that day, so I used the back up sights and discovered that the Virtus is a very accurate rifle out to 25 yards. I was putting pellet on pellet at 15 yards. It’s a quiet rifle too, though I will need to test it alone and away from a firing range — hint-hint, Sig!

Virtus
Sig Air Virtus is a tactical-looking semiautomatic PCP. 

Virtus Tom

Once I switched to open sights, the Virtus was stacking pellets!

P365 BB pistol

I was surprised to see that the Sig P365 BB pistol is back — and apparently has been for more than a month. That’s one I’m in the middle of testing and need to complete sometime soon — another hint Sig!

Virtus airsoft

Sig Air will be bringing in more airsoft replica guns this year. I have tested the M17 already, but not the new M18 that’s the sidearm of several US armed forces. Sig’s Matt Handy showed the guns to me off the range and then I was able to shoot the new airsoft Virtus on the range. I hope to test that one for you this year, as well.

Airsoft Handy

Matt Handy holds the new Sig Virtus airsoft gun.

Smart Shooter

As I was leaving the range I was buttonholed by Hadas Weizman from Smart Shooter. He told me about a new weapons system where the shooter doesn’t have to be that good a shot. Smart Shooter is an electronic sighting system that controls the firing of a rifle. You hold the sight on the target and press a button until the sights draws an illuminated box around the target. Then you release the button and pull and hold back the rifle trigger. A large illuminated cross forms in the sight and you swing that over to the target. When the computer senses the shot is good the rifle fires.

Smart Shooter

Hadas Weizman holds the Smart Shooter training device that he trained me on.

I was trained in five minutes and then turned loose with a live rifle. I hit the moving target in the head twice at 100 yards from the offhand position.

Smart Shooter Tom

I hit the 100-yard moving target twice in the head.

After I finished shooting the Sig guys looked at each other and wondered why the target’s head had snapped back but the whole target had not dropped. They then shot the target in the body and got it to drop. I was told that I had at least wounded the target and that was the goal. Ha, ha!

They told me that a battle rifle is not a precision weapon and center of mass shots are best. But I just thought, “Two in the head and you know they’re dead!”

Smart Shooter moving target

This is a standby life-sized moving target for the Smart Shooter range.

It’s over

Sig Range Day was over for me but I do plan on stopping by their booth to talk more with their reps. I want to get a better feel for what 2020 holds for Sig Air.

Media day at the Range

This Media Day was better organized than ever before. The bus dropped us off at the top ranges where the two airgun ranges happened to be, and all we had to do after that was walk downhill. Even I can do that!

Umarex USA

Almost across the street from the entrance was the Umarex USA range. They were showing both of their arrow launchers and I got a chance to shoot both of them.

Air Javelin

The first one is the budget-priced Air Javelin that’s powered by CO2. It accepts a large 88-gram cartridge, and, though I saw about 10 shots fired, I never saw the cartridge run out of gas. It was 50 degrees, Fahrenheit, that day so I will have to test this one for you myself! Hint, hint — Umarex!

It shoots at over 300 f.p.s. which made me think it was capable of taking deer until I realized that the hollow arrow shaft makes the arrow weigh just 120 grains. It probably could take a deer up close, but that’s not what I would recommend. The guys at the range were talking groundhogs, rabbits and raccoons for this one.

Yes, the arrow is hollow and fits over a long tube in the gun. The air seals quite well, and there is very little impulse when the gun fires.

Umarex Air Javelin

To load an arrow into the Air Javelin I had to look at the slim tube inside the firearm, because the hollow arrow shaft fits it tight.

Umarex Air Javelin Shoot

The Air Javelin was quite accurate at 20 yards.

Air Saber

The Umarex Air Saber is their big dog this year. It launches a hollow 276-grain carbon fiber arrow at 450 f.p.s. This one runs on high pressure air, so it’s a PCP. It operates at 250 bar or 3,625 psi. I’ll have to wait to test one to give you a shot count per fill, but I never saw it run out of air while I was there.

They had a bipod on the range gun and I very nearly shot a Robin Hood at 25 yards, though I purposely tried not to. This arrow launcher is so powerful that they stuck arrows with field points so deep in a 3D jackalope target that they could not pull them back out! For those who don’t know, a jackalope is a mythical cross between an American jackrabbit and an American antelope.

Jackalope

You see a lot of mounted jackalope heads in southwestern bars in America.

Umarex Air Saber

The Air Saber is a powerful PCP airbow.

Umarex Air Saber Tom

The Air Saber was surprisingly accurate at 25 yards. I almost Robin-Hooded, even though I tried not to!

Constant Acceleration Pneumatic Arms

These guys are new to the world of big bores, though I have been communicating with one of the founders, Mark Cherry, for a couple years. To be honest, I didn’t think I would ever see anything come from our talks, but Mark persevered and brought his creation to Media Day. I will first show you the info sheet at their range.

Cap Dragon

This sheet says it all except the experience of shooting the gun.

Light gas

No, light gas is not 90 minutes after you eat onions! It’s a blend of Helium and other light gasses that flow faster than air because their atoms are smaller. I have known for a long time that it’s possible to get much higher velocity from an airgun when you shoot it with Helium, but there is a big problem. Or a very small one, to be more specific! The tiny Helium atoms are so small that they aren’t easily contained by valve seals and o-rings that are designed to hold air. Besides costing a lot, Helium will make a precharged airgun leak!

Well, these guys may have found a solution or solutions for that. The Dragon I shot was tethered to a tank, so lots of gas was being used, but they were also letting the media shoot, so maybe that was just the prudent thing to do.

All I know is I smacked the target at 40 yards on the first shot, with a 350-grain bullet that developed over 700 foot-pounds at the muzzle. The gun kicked like a .357 big bore, which stunned me. Apparently that “thin gas” also absorbs a lot of the firing impulse.

CAP Dragon Tom

The recoil was mild.

They told me their patented valve design maintains constant pressure on the bullet all the way down the bore. A larger valve passageway, longer valve dwell time and that thin gas all contribute to the amazing power that’s claimed.

Not done yet

Old BB was then finished with airguns, so he moseyed down to the other end of the range, sampling all the ranges along the way and stocking up on giveaway SWAG (hats, shorts, cupholders, pens, etc.). I thought I was done until I happened by the Rambo pavilion. There I met Kelle Adams of ShopBadAss.com. She was offering free rides on electric-powered desert bicycles! Would I like to try?

WOULD I?????

So there I am, all 235 lbs. of balding fat man, perched on a fat-tired mountain bike and racing across the Nevada Desert like Jabba the Hutt on a unicycle. No I didn’t fall. And no, I didn’t allow photography. Some things like car crashes, modern art and pictures of me riding a bicycle are best kept private.

Why am I telling you this? So you will tell your wives and they will give you some snappy comebacks to lay on me. You see, that was Edith’s job. Who is gonna pick up a 72-year-old curmudgeon when he piles up his bicycle at 30 mph?

Rambo

I want one!

That’s all

That’s my report for today. The show opens tomorrow and I hope to have a lot more to show you!


Diana 27S: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Diana 27S
Diana 27S.

Part 1
Part 2

A history of airguns

This report covers:

  • SHOT Show
  • Odd-sized breech seal
  • Grainger
  • Velocity with Air Arms Falcon pellets
  • Fooled around
  • WHAT!!!?
  • On with the test — JSB Exact Heavy
  • Chronograph error
  • Cocking
  • 27S
  • Cocking behavior
  • Firing behavior
  • RWS Hobby
  • Summary

SHOT Show

I’m at the SHOT Show today. Today is Media Day At The Range, so I’m looking at all the new airguns that are on the range in Boulder City. Yesterday I went to Sig Range Day, so tomorrow I will have a report on both events. The show opens on Tuesday, so the Wednesday blog will be my first report from there.

Today we look at the velocity of the Diana 27S we are testing. If you recall, in Part 2 the breech seal failed and I couldn’t test the rifle. I replaced the seal with a temporary leather one and the velocity jumped from the mid-300s to the high 600s. I said then that it was the largest velocity increase I have ever seen from just replacing a breech seal. I expected a gain of 60-80 f.p.s. Several readers made similar comments.

Odd-sized breech seal

When I measured the old seal I expected to find numbers that were even, numbers that made sense! Instead I found the old seal’s material diameter (the thickness of the ring) was 2.4mm. The inside diameter was 8.3mm and the outside diameter was 13.1mm. Okay, where is the camera — I’m on Candid Camera, right? I expected a ring with a thickness of 2.5mm, an ID of 8.5mm and an OD of 13mm. Who would make something common like an o-ring with such random and odd dimensions? The ring wasn’t designed for Diana. Diana selected the ring from what was available and designed their airguns to fit.

Apparently, though, someone did design a ring like this because when I went to Grainger looking for one, there it was — 2.4mm by 8.3mm by 13.1mm! The reason I was so skeptical is because when it comes to measuring things I’m a cut-three-times-measure-once-and-then-hire-somebody-else-to-do-the-job kinda guy. But, listening to all of you guys with skills, I figured I could at least give it a go — might provide some fodder for a funny blog!

Grainger

So I placed an order with Grainger for 25 o-rings. I have about 6-8 Dianas that need these seals, and the way I love these guns more can come at any time. The rings arrived last week, and, with considerable trepidation, I installed one in the 27S. Then I set up the chronograph and fired the first tentative shot.

Diana 27S breech seal
The new o-ring/breech seal from Gainger fit perfectly.

Velocity with Air Arms Falcon pellets

Okay guys, we will start the velocity test with the Air Arms Falcon dome pellet. Ten Falcons averaged 689 f.p.s., for an average muzzle energy of 7.73 foot-pounds. Remember — the magic number of 671 f.p.s. is the velocity at which the energy of the pellet in foot-pounds is equal to the pellet’s weight in grains.

The spread ranged from a low of 672 to a high of 710 f.p.s. That’s 38 f.p.s., which is high.

Fooled around

After that I shot some more Falcons and got a string of three that measured 320, 309 and 310 f.p.s. — WHAT!!!?

WHAT!!!?

Right after installing the new breech seal and shooting the gun at velocities in the 690s, I suddenly got one at 374 f.p.s. And that is when it hit me. The new breech seal DOES NOT add 300 f.p.s. to the velocity of the rifle! I had shot through the chronograph in such a way that the first skyscreen was triggered at the wrong time. I know that because I can now do it anytime I want.

It isn’t common but I have seen this phenomenon before. If the muzzle of the gun is too close to the first skyscreen (with Shooting Chrony chronographs) you will get a reading like this. In the case of this Diana 27S I also have to point the barrel slightly downward by a few inches at 3 feet to make it happen every time. That is what happened in the last test, but I didn’t catch it until today. It was just the way I was sitting that made it happen. Apparently the Diana 27S is just long enough to put the muzzle in the exact right spot for this to happen.

So — chronograph users beware. And everybody — a new breech seal should not increase velocity by 300 f.p.s. unless there was no seal to begin with!

On with the test — JSB Exact Heavy

Next up is the JSB Exact Heavy pellet. At 10.34-grains this dome is on the heavy side for a rifle of this power but I have seen excellent results from such pellets in weaker airguns in the past. Ten JSB Heavys averaged 555 f.p.s. from the 27S. The spread went from 552 to 560 f.p.s., so a difference of just 8 f.p.s. At the average velocity this pellet generates 7.07 foot-pounds at the muzzle.

Chronograph error

I got two “Error 2” messages on this string. That message means that skyscreen 2 isn’t seeing the pellet. This is something I am familiar with. Unless the pellet missed passing over the skyscreen it means something has fallen onto the widow above the screen’s sensor. As close as I shoot I knew I wasn’t missing the screen, so it had to be an obstruction. When I looked I saw exactly what it was and was able to clean the screen and get going again.

Diana 27S skyscreen
I shoot with the chrono so close to the pellet trap that stuff sometimes falls on skyscreen 2. There is a smashed lead pellet on the left and a large piece of paper on the right. Remove all the stuff and wipe the screen window with a cotton swab and you’re back in business!

Cocking

I reported in Part 2 that the 27S cocks with 24 lbs. of effort. That’s more than I expect from a Diana 27, but this isn’t a 27 — it’s a 27S.

27S

The Brits call the 27S the 27 Super, and apparently it was sold to them under that name. They also know of a 35 Super model that I never heard of. Well, looking at both the cocking effort and just the velocities we have seen thus far I think the 27S is more like the Diana 35 than it is like the Diana 27. In fact, the Diana 35 that I tested and tuned last year shoots at lower velocities than this one.

Cocking behavior

The 27S cocks with a slight scraping noise that is common to rifles that have two-piece articulated cocking links. The solution is lubrication, which I will apply when I go inside.

Firing behavior

This rifle shoots with a jolt and a lot of buzz that isn’t common for the other vintage Dianas I have experienced. I will have a look around inside for what can be done and also to see what that anti-beartrap mechanism looks like. But while I’m inside I will lube the rifle with Tune in a Tube in both the mainspring and ball bearing trigger areas. In fact, I am curious to see whether the ball bearing trigger in the 27S looks like the one in a 27 or the one in the 35 that has a few additional parts.

RWS Hobby

This is the last pellet to be tested. RWS Hobby was the speed demon of its day, which was contemporary with the vintage Diana line we have examined. I have found in recent tests that Falcon pellets, though slightly heavier, are often faster, but we shall see.

Ten Hobbys averaged 660 f.p.s., so true to form they are a little slower than Falcons. However, the Diana 35 that I tuned last year averaged 601 f.p.s. with a 26 f.p.s. velocity spread with Hobbys. Today the 27S low was 650 and the high was 671 f.p.s., so the spread was 31 f.p.s. At the average velocity the Hobby generates 6.77 foot pounds.

Summary

That’s it for this report. The new breech seal tells us what we need to know about this rifle — it’s in good condition and probably shooting like it did when new.

I would also like to add that today was a big learning day. We learned or were reminded about some quirks of chronographs that I hope will help some of you.

The next report will be a disassembly and examination of the insides of the 27S. And, if it cooperates, I will give it a lube tune and button it back up for another velocity and firing behavior report to follow. So, stay tuned!