The air transfer port Part 2

by B.B. Pelletier

First, an announcement. The 2008 International Airgun Expo is coming up in just a few weeks (Oct. 24 & 25). I make it a point to drive out from Texas every year to attend the show. It's THAT good! Pyramyd Air will be there again this year. Like last year, they'll have loads of new and used guns, scopes, accessories, a boatload of pellets and just about anything else an airgunner would want. If you didn't go to the Pyramyd Air garage sale last month, then here's another chance to get in on some good deals. Go to the show's web page for time, location, a map and a list of hotels.

Now, on to today's blog.

Part 1

There's a lot of interest in this subject. More than I would have guessed. So I'm running this second part today to give you something to talk about this weekend. Let's look at the shape of the transfer port as it relates to efficiency.

Many air transfer ports are simply straight holes bored through the end of the compression chamber. I'll discuss the size of those holes in the next and final report, but it's surprisingly similar across a wide variety of air rifles. Today, we'll look at transfer port holes that are not just straight tunnels.

Stay away from mirror-smooth
In a discussion I had with Jim Maccari, I was cautioned to not polish a transfer port to a mirror finish (assuming I could have done so). Jim told me his experience was that super-smooth transfer ports are not as effective as those that break up the airflow to some degree. In fact, he shared one of his tuning secrets - a transfer port shape he likes to use on lower-powered air rifles like the FWB 150 and 300, which are both target rifles. Both have a concentric transfer port, so this tip may work best for them and not as well for guns that have slanted transfer ports.

Jim's tip is to bore several graduated sizes of holes on the compression side of the transfer port - making a sort of bizzaro funnel, if you understand the Superman reference. A stepped funnel if you don't.


Seen in cross-section, a stepped port is cut from the compression side only.

According to Jim, this makes the rifle shoot smoother. I presume it's breaking up the airflow by creating eddies and swirls at each of the corners of the steps. I have no personal experience with guns using this kind of transfer port.

The changeable transfer port
I wanted to test several theories about transfer ports, and Dennis Quackenbush was kind enough to make up several ports that I could install in an R1 compression tube that Jim Maccari donated. Ironically, Jim donated this tube because it was ruined by an airgunner who drilled out his transfer port for more power. Of course, that didn't work and his rifle was ruined, so he went to Jim for repairs.

Dennis drilled out the port even larger and made up several transfer port inserts that could be installed from the outside of the gun in less than a minute. I had an excellent testbed for testing transfer port sizes and shapes.


Dennis Quackenbush made this set of removable air transfer ports so I could test various sizes and shapes for the R1 book. The port in the center actually has a Venturi shape.


Jim Maccari donated this compression/spring tube, and Dennis Quackenbush machined it to accept his quick-change transfer ports. When built into a rifle, it is a great testing tool!

What about a Venturi shape?
This question always comes up because we know the Venturi shape increases the speed of the air flowing through the port. When I did the transfer port test on the R1, I asked Quackenbush to make some ports that approximate a Venturi shape. The shape he made is shown below.


Seen in cross-section, this Venturi port has a bevel on both ends of the port.

I copied the shape after the port on a Webley Patriot, which is similarly beveled at both ends. I figured if it worked for the Patriot, it might also work for my R1. However, I saw no increase in speed with this shape. It may have been too large and may have reduced the compression by adding too much additional volume, like a slanted port. I don't know. I do know is that there was no increase when using the Venturi port when compared to a straight port of the same diameter.


Webley Patriot port is beveled like a Venturi, but the bevel is very shallow.

A shape that might be worth trying
Here's a shape I never tried, but one that I think might hold some promise for airspeed improvement. The trick will be to get the angle correct, so the total volume doesn't drop compression too low and offset any potential gain.


An interesting transfer port shape that I've never tried.

I bet you never thought there was so much to a simple thing like a transfer port, eh? It's not just where it's located, but also how it's shaped and even how much volume it contains. Next time, we'll look at the diameter of the port, which was the question that started this report in the first place.

Starting your own field target club Scoring

by B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5

Scoring field target is really what the game is all about, because every shooter is in it for the score. And, all of you know by now that successfully knocking down a target gives the shooter a point, just as leaving it standing earns no point. What could be simpler than that?

What if the target falls halfway back, or not even halfway, but the paddle moves out of the kill zone? What if the paddle falls all the way back, but the target continues to stand? What if the paddle goes back as if to fall, then comes right back to where it started? I've seen all of these things in a match and had to make a decision or ruling about them so the match could continue.

The alibi
When a target doesn't behave as it's designed to, or whenever a shooter thinks it isn't behaving as it ought to, he can call the shot an alibi. He marks his scorecard with an alibi for that target and, if possible, tells the match director so he can get a ruling and possibly a fix. If he's shooting twice at every target, he can mark the number of times the target misbehaved. It may have been fine for one shot but an alibi for the other.

When there's an alibi, the match director must decide what to do about it. If the target seems to be malfunctioning and there's a replacement available, he can stop the match and swap targets; but that slows the match, and the people who shot before the swap will feel slighted if they didn't get a perfect score. Or, the match director can declare that target to be out of the match and nobody will get credit for shooting it. That's the best way to handle it in most cases. However, beware of "Alibi Ike."

Alibi Ike
Alibi Ike is an age-old shooting nickname for that shooter who seems to have more problems than anyone else. Run a few matches, and you'll meet him. He takes longer to shoot, has problems with just about everything and will always have the most alibis in a match. Once I figured this out, I learned to let other good shooters have a go at the "bad" target before knocking it out of the match. I was lucky in having a half-dozen nationally-ranked shooters at my club, any one of whom could prove or disprove the alibi with one shot.

Beware of the intermittent alibi
When a target is emplaced poorly, it may have marginal performance. This is especially true for targets that use gravity to operate. A 20 foot-pound gun may smack it down, while a 12 foot-pounder may not. I test every target with a 3 foot-pound air pistol after emplacement, but constant tugging on the reset string can move them around after awhile.

Scorecards
The scorecard has a place at the top to record the shooter's name, his rifle, scope and pellet (people always want to know this after the match) the date and the lane his squad starts on.

The scoring section has a place to register hits and misses for every target and lane, as well as the total hits for that lane. At the bottom of the card or sheet is a place for all the lane scores to be totaled. I had shooters mark their alibis with a note in the margin on the same line as the lane where it happened.


This is what my scorecard looked like. We had 12 lanes with three targets on most of them and two shots per target, so each had a row like this. This is lane 11, which is worth as much as 6 points.  Near, middle and far refer to the targets on each lane. An X means a hit and an O means a miss.

Scoring
We put the three scorecards for each squad on a clipboard with a pencil for scoring. They received the clipboard at the match director's briefing. It was up to them to keep their own scores. At the end of the match, they turned in the clipboard and the scorecard was checked by the match scorer (usually my wife). She would count all the hits for each lane and found a surprising number of errors in every match. Once they were confirmed, the scores were entered on a tally sheet for the match and then prizes were awarded.

I found that shooters around the country were very interested in the results of our match, because they wanted to track certain shooters. Getting the scores up on our website was another important task. I tried to get them up within a few days of the match. If I didn't, the phone started ringing.

That's about it for running a club. There's a lot more, of course, but they're the kinds of things you learn by doing. Next, I'll discuss the use of scopes in field target and the pros and cons of adjusting the elevation for every shot versus holding over.

The air transfer port Part 1

by B.B. Pelletier

When I was writing the R1 Homebrew series of articles for The Airgun Letter, I did lots of side experiments and research to discover what tuning tips did and didn't work. In the area of air transfer ports, I discovered a lot that wasn't documented at all, and more that was known to only a few people. Apparently, the air transfer port is one of the most modified areas of a spring gun, yet very few people are doing any research on the effects of modification.

What is an air transfer port?
At the end of the compression chamber, there's a small hole that the compressed air passes through after being compressed by the piston. That's the air transfer port. In a spring gun, the amount of compressed air is extremely small when compared to a pneumatic. As early as 1948, the gunsmith and pistol competitor Walther F. Roper surmised that it wasn't the volume of compressed air that makes a spring gun work but the speed at which the air is compressed and released. Three decades later, the Cardews of airgun experiment fame agreed with his observation.

When seen in cross-section, the air transfer port is actually a tunnel that runs from the compression chamber to a point immediately behind the breech, where the pellet sits. The compressed air rushes through this tunnel and blasts into the skirt of the pellet, sending it on its journey down the barrel. How this port or tunnel is made and where it's positioned play a large part in the efficiency of the air blast, which determines the rifle's efficiency.


Seen in cross-section, the pellet seals the front of the air space and the piston seals the rear (piston is to your right and not shown in this drawing). This is the air volume that gets compressed when a spring gun fires.

Don't think for one minute that this design is easily understood, despite being so dirt-simple. Jack Lewis, a famous gun writer and editor of the 1950s and '60s, saw a cutaway like this and thought the empty space he was looking at was a valve. He described that phantom valve in detail in a 1960s article about spring-piston rifles--not unlike the amateur astronomer Percival Lowell describing the canals on Mars. But now you know what it is--the space between the piston seal and the pellet. It's the part that's the air transfer port that interests us.

Air transfer ports are placed where they have to be because of the gun's design and also in order to do their job. Their job is simple--pass the compressed air from the piston to the pellet. Since they're open all the time (being nothing more than passageways), they form a part of the total volume of the compression chamber, even though they're not inside the chamber. Understanding that is important to understanding what comes next.

Concentric ports versus offset ports
The piston is a large hollow slug of metal that's pushed by either a coiled steel spring or by a charge of compressed gas in the case of a gas spring. In front of the piston is a seal that keeps the air from escaping. The compression chamber is in front of the piston, with the air transfer port forward of it. At the end of the air transfer port is the breech of the barrel, which is sealed by a lead pellet. The volume of air behind the pellet and in front of the piston gets compressed when the piston rushes forward.

Where the hole is located plays a large part in the efficiency of the transfer port. If the hole is in the center of the compression chamber, the air flows evenly from all around the chamber and into the port. If the hole is offset, some of the air has farther to go, resulting in a decrease in the intensity of the air blast behind the pellet. That's because some of the air is still flowing through the port after the initial shock wave has hit the pellet skirt and started the pellet on its way.


The central transfer port is more efficient than the offset port. Pardon the distortion in this image. It was scanned from the Beeman R1 book.

Some air transfer ports are offset rather than centered or concentric because the barrel is a smaller diameter tube than the compression tube. It sits atop the compression tube, making the transfer port offset. The Feinwerkbau 124 (and other spring guns) has a transfer port opening in the center of the compression chamber, but it also aligns with the center of the breech. To do that, the port is cut on an angle.


An angled transfer port centers the port in both the barrel and the compression chamber. To be angled, it must be longer and, therefore, loses efficiency.

Unfortunately, when the port is cut on an angle, it has to be longer, and the extra length adds volume to the compression chamber--remember that? Extra volume means the air cannot be compressed to the same degree, and, if we are correct about the intensity of the air blast being more important than the amount of air compressed, well, then it becomes a very big deal.

The TX200 has a curious humpbacked appearance, because the barrel is lowered to align with the center of the compression chamber. Hence, a light spring can produce great power with less effort. The RWS Diana 48/52/54 is designed the same way and produces similar results. The majority of airguns are not designed this way, so their transfer ports either have to be offset or longer to carry the air where it has to go.

This was just our first look at the subject. Before you can appreciate how the size of the transfer port affects things, you have to understand the design of the transfer port.

BAM B26-2 thumbhole Part 2

by B.B. Pelletier

Part 1

We saw a lot of emotion over this gun in the remarks after the first report. Some of you seemed to be against it because of where it's made, and others had read criticism into my report that I didn't put there. I'm only here to report what I see and experience when I test these airguns, and the BAM B26-2 is a very nicely-made gun. If I gave any other impression, please forgive me. Yes, I did comment that the trigger is not a Rekord, but two readers advised me how they got a first stage from theirs, so there are definite possibilities.

Today, I'll look at velocity. You'll recall that I tested the cocking effort at just 24 lbs. If the rifle turns out to deliver 900 fps velocities, it will be very significant.

Clean the barrel
The first step is to clean the barrel with J-B Non-Embedding Bore-Cleaning Compound. By this time, you know the drill. I like to clean the barrel of all new air rifles if possible, to remove latent bluing salts, rust and factory dirt. However, I'll clean only those guns that lend themselves to it. I don't clean guns with sliding compression chambers and most PCPs, because I can't clean them with a solid rod from the breech. Those guns I just shoot until they're clean.

I removed the muzzlebrake before cleaning the barrel, simply because it's less of a hassle off the gun. JB paste can get stuck inside if you leave it on. The barrel proved to be very smooth and had no choke. There was some dirt inside the bore, but nothing nasty like rust. Once clean, the rifle was ready to be tested.

Velocity with Air Arms Diabolo Field domes
Air Arms Diabolo Field domes are made by JSB, so you know the quality is there. Once the rifle settled down, they averaged 709 f.p.s., with a spread from 694 f.p.s. to 723 f.p.s. That works out to an average muzzle energy of 9.42 foot-pounds for this 8.44-grain pellet.

Velocity with Crosman Premier lite pellets
Crosman Premier 7.9-grain pellets averaged 750 f.p.s. with a spread from 744 f.p.s. to 759 f.p.s. They seemed to fit the breech very well, which may be a hint of accuracy to come. The average energy was 9.87 foot-pounds.

Velocity with RWS Club 10 pellets
RWS Club 10 pellets are 7.0 grains, the same weight as RWS Hobbys, so I used them as my 1990s-era lightweight pellet. Once the rifle settled down, they averaged 854 f.p.s., with a spread from 839 f.p.s. to 869 f.p.s. That works out to an average energy of 11.34 foot-pounds.

Velocity with Crosman Silver Eagle hollowpoint pellets
Crosman Silver Eagle hollowpoint pellets weigh just 4.8 grains, and will usually give the highest velocity of any metal pellet. They averaged 1110 f.p.s., with a huge spread from 1009 f.p.s. to 1151 f.p.s. Only two shots out of 10 registered under 1100 f.p.s. The average energy was 13.14 foot-pounds, a number that is very interesting.

It straddles the fence!
By UK law, this pellet would make the B26-2 a firearm, since the energy is greater than 12 foot-pounds at the muzzle. And that should open your eyes to the precarious position airgun manufacturers find themselves in when trading in the UK market, since any new lightweight pellet has the potential to do this. Once a model tests above 12 foot-pounds, it's always and forever considered a firearm. Not just one specific gun, mind you--every gun made under that model number. If you bought it as an airgun and a new pellet pushes it over the limit, that's your bad luck! Spring guns are especially vulnerable to this because precharged guns don't normally vary quite as much.

What a spread of performance! From a low of just 9.42 foot-pounds to a high of over 13. That illustrates just how much it matters when choosing a pellet for an air rifle. U.S. shooters don't have to concern themselves with velocity or power, of course, so they can concentrate on accuracy and choose the best pellet they can. Next time, we'll find out what sort of capabilities this rifle can deliver. The .22 caliber B26 was pretty accurate, so I'm hoping this one will be, as well.

HW 55 Tyrolean - part 3

by B.B. Pelletier

Part 1
Part 2

Today, I'll start disassembling Wayne's HW 55 Tyrolean rifle to see what it looks like on the inside. Wayne bought this rifle on my recommendation and at a price that guaranteed a good investment from the start. From the firing behavior and other visual clues, the rifle seems to have been recently tuned. We will discover whether that assessment is true once we get inside. Also, there were a couple of concerns with the rifle. The Rekord trigger, which in the 55 is a special target version capable of extraordinary lightnesss with positive safety, has been adjusted rather heavy. It's not even as light as a sporting Rekord, which is nowhere near as fine as a target Rekord can be. So, I'll look into adjusting it and anything else it may need. Additionally, the cocking link drags over the mainspring when the barrel is closed after cocking. I've felt this before in other spring guns, but I'm going to have a close look to see if anything can be done.

A little R1
This rifle is constructed like many classic Weihrauchs, so there's a lot of similarity between it and the Beeman R1. Of course, the HW 55 is nearly three decades older than the R1, so perhaps it's more correct to say the reverse--that the R1 is a big HW 55. The point I'm making is that the 13-part blog I did on tuning a spring gun, which was based on an R1, holds true for this rifle, as well. There are some subtle differences besides the scale of the two rifles, and I'll cover those as we come to them. You might want to review that tuning report, as I may have touched on a few things that I'll not put into this report.

No safety
Step one is to remove the rifle's action from the stock. Before doing that, let's look at the first significant difference between an HW 55 and most other Weihrauch spring rifles. The 55 has no safety! The automatic safety was added to the line, model by model. At one time, none of them had it. I guess it seemed right for the sporting models, because that's where it ended up; but, since target guns seldom have safeties, it never made it to the 55 model, as far as I know. If anyone knows differently, I would be happy to be enlightened.


As far as I know, the HW 55 never had a safety.


This Beeman R1 has a safety button. Incidentally, this is the R1 that was the star of the book.

The Weihrauch safety is a spring-loaded pin that jumps into position when the rifle is cocked. If you want to reapply it after taking it off you have to break the barrel again--on the cocked rifle--so the piston rod can press the trigger parts out of the way, once more. Eliminating the safety does nothing to the function of the trigger, which remains a modular unit. But what it does do is remove one additional step a competitor has to remember while shooting a match. However, the 55 adds another step of its own, in the form of the breech lock lever, so it's really a wash. R1 owners get so used to releasing the safety that they never give it a second thought, anyhow.

Separate the action from the stock
The 55 has an articulated 2-piece cocking linkage, which means there is a steel bridge under the spring tube that the linkage passes through. That also means that instead of 2 forearm screws--one of either side of the gun--there's just a single screw in the bottom of the forearm that screws into a threaded bushing in the steel receiver bridge. HOWEVER--important tip--instead of just the front triggerguard screw holding the triggerguard and therefore the stock to the action - BOTH the front and rear screws hold the rifle together. The rear triggerguard screw actually threads into a nut held captive by the trigger housing. So, it still takes the removal of three screws to separate the stock and action.


Only a single forearm screw and a short cocking slot are features of an articulated cocking link.


On the 55, both triggerguard screws hold the rifle in the stock. The front screw fits into a boss on the spring tube. The rear screw fits into the rear of the trigger housing. That's the last hole on the right in this picture.

Remove the trigger
To remove the Rekord trigger, drift the two crosspins from left to right. Drift the front pin first and install it last during assembly. I will explain the special assembly procedure when we get to it. Once the trigger was out, I saw a strange and somewhat disturbing thing. It was still greased from the Weihrauch factory with what I call "tractor grease." Once you've seen this stuff, you'll never forget it. It's a clear sign the trigger has never been touched, but the mainspring that I can now see is coated with black tar. Who removes a mainspring and coats it with tar but fails to clean and adjust a Rekord trigger? There's an obvious answer to that, but I held my opinion until the mainspring was out.


Drift out the 2 crosspins that hold the trigger to the rifle.


The thick transparent brown grease that covers the trigger parts is a telltail factory sign. This trigger has never been cleaned or adjusted since new.

Remove the end cap
Once the trigger has been removed, there is a huge hole in the end cap. To get the threads started I insert the smooth end of a medium-sized crescent wrench into the hole and strike it on the the other end with a hammer to start the threads turning. It only takes two or three strikes on the wrench before the end cap can be unscrewed by hand. The smooth rounded end of the wrench ensures there will be no marks left on the sharp edges of the trigger slot.


Once the trigger is out, there is a deep slot where it was housed. The smooth rounded end of a 10-12-inch crescent wrench can be inserted in this slot and used as leverage to turn the end cap.


The end cap is threaded into the spring tube.

As you can see, the end cap simply unscrews from the spring tube. When the threads get near the end, I place the muzzle on a piece of wide leather (the inside of my sandal works for this) so the whole rifle can rotate while I hold the end cap still and exert downward pressure. When the threads end, the cap springs up with about one inch of spring tension, which is 30-40 lbs. of effort. I'm not using a mainspring compressor with this gun. I've always done it this way with the smaller Weihrauchs, and I know that other airgunsmiths do the same. If you don't know what you're doing, use a compressor.

The mainspring will now pull out. Once I have it in hand, my suspicions are confirmed. It's canted. That means this gun was not tuned by a professional. It has what is known as a redneck tune. Someone put black tar on the bent spring to calm the gun. It's like a politician paying hush money to cover his tracks instead of solving the problem. This spring will not be going back into this rifle.


This is the correct amount of black tar for a mainspring.


And there's a problem. A canted mainspring will make the gun buzz and produce less power. The last person inside the gun used black tar to quiet the buzz instead of replacing the spring with a good one. That may be where the dragging cocking link came from.

I'm going to stop here because this has become a lengthy process. Next time, I'll complete the teardown.

Steel Dreams - Part 2 Building a more powerful spring-piston gun

by B.B. Pelletier

Part 1

Lots of interest in this story! I should have told it long ago. One of our readers may have actually seen the rifle at the recent airgun and firearm show in Frederick, Maryland.

With the last report, we left off with an external examination of the rifle. Naturally, as a red-blooded airgunner, I put it through the chronograph first thing. The cocking effort was 53 lbs., compared to a Beeman R1 that cocks with 36-41 lbs. of force. So, while the rifle isn't the heaviest-cocking springer I've ever tested (that distinction belongs to a Hatsan 135 that took 75 lbs. to cock), it certainly wasn't built for casual plinking.

The firing behavior was harsh. There was a huge lunge forward plus lots of vibration. The big lunge means a heavy piston, and the vibration usually means a canted mainspring. I said last time that the barrel was an Anschutz, but I found that Steve Vissage told me he thought he remembered putting a Webley Ospry barrel on the gun.That would have had the proper dimensions for a .22 caliber pellet.

The velocity I got with 14.5-grain Eley Wasp pellets was 755 f.p.s. I checked with the two .22 caliber R1 rifles I used in the R1 book, and they averaged 725 f.p.s. and 751 f.p.s. after 1,000-round break-ins. Steve Vissage remembered a velocity of around 800 f.p.s. with this gun, but that could have been with a different pellet.

Then, I disassembled the rifle. I was all set to use a mainspring compressor, but Steve told me the mainspring was under about a half-inch of preload. So, I removed those three machine screws and the one triggerguard screw, and the end cap popped up by less than a quarter-inch. I guess over time the spring had scragged (taken a set length from which it will never diminish until it wears out).


Not a lot of spring preload. Vissage saved some money by not threading the end cap like a Weihrauch.

With the end cap off, the mainspring came out, and it's a monster! Its 32.5 coils are made from 0.190" ASTMA 410 silicone chrome wire. The compressed length is 6.175", which must be a record for spring rifles. The mainspring weighs 12.2 oz.

An R1 mainspring weighs 6.3 ounces, in comparison, or just over half what this one weighs. Look at the photo for a comparison.


Guess which spring goes in the Vissage rifle? The R1 spring on the left is worn-out and canted. The Vissage spring is also canted, although this picture doesn't show it.

The piston came out next. It weighs 18.2 oz. and is 1.30" in diameter, while an R1 piston weighs 12.6 oz. and is 1.147" in diameter. Vissage had the piston tempered and shot-peened to relieve stress. The piston rod was hardened and drawn to a dark straw color. That should make it file-hard. The spring guide is also proportionately larger than the R1 guide.


Vissage's piston weighs over a pound and dwarfs the R1 piston beside it.

A close examination of the piston seal revealed several flat spots, which are burn marks from excessive friction. Vissage told me he put a lot of effort into the selection of material for the piston seal. He was looking for high-lubricity and tolerance for high-temperatures from the heat of compression. Those flat spots told me the seal was too dry and was wearing from the friction with the chamber.


See the flat spot that's facing you? That's a burn due to friction.

After seeing the massiveness of these parts, I felt that some velocity was lost by a slowdown in acceleration of the piston. The weight of the piston told me where the rifle's powerful forward lunge was coming from. However, before you start criticizing Vissage, let me tell you that Jim Maccari once made a plastic piston for a TX200 to accomplish just the opposite - faster acceleration from lighter weight. That gun vibrated like a jar full of mad hornets, so you can go too far either way.

The piston seal is not a parachute design. Perhaps there's some loss of pressure around the sides, where the high-pressure air has nothing to confine it. A parachute seal would inflate and push its sealing edges against the cylinder walls, but this seal can't do that.

I lubricated the piston seal with Beeman M-2-M moly grease before installing it again. The mainspring received a coat of Maccari's black tar to cut the vibration. All friction points received a coat of M-2-M grease. The thin washers at the pivot point had never been lubricated. Steve counted on the Armaloy plating to self-lubricate, but I found it mostly scraped away when I disassembled the rifle. So, I used moly paste on the washers, and the cocking got smoother.

When the gun was back together, it felt like the cocking effort had diminished, when in fact it had actually increased by 2 lbs.! It was smoother but also a little harder to cock. The velocity with Wasps averaged 776 f.p.s., but that dropped to 767 pretty fast. I imagine the rifle will sink back to 755 in time. It vibrated much less this time, though there was still some present.

Sorry to say that I never shot the Vissage rifle for accuracy. I was more interested in how the powerplant performed; and, as we saw, it was about like a factory R1.

When I tuned a standard Beeman R1 with a Venom Mag 80 Laza kit, the average velocity with Eley Wasps jumped to 840.8 f.p.s., and the firing behavior was as smooth as glass. The Venom kit was the first to offer Delrin button bearings to float the piston in the spring tube. It took 50 lbs. of effort to cock, but the return was a much more powerful air rifle.

That's the tale of a man and his quest for speed. The other two rifles he built were a .177 and a rifle with both .177 and .22 barrels, which he kept for himself. Vissage never went supersonic in .22 caliber, but I bet he knew a lot more about what goes into a powerful spring rifle after this project was over! And, now, we all know a little more.

BAM B26-2 thumbhole Part 1

by B.B. Pelletier


BAM B26 is a well-done copy of the Beeman R9.
Before I begin, I received a packet of vintage Daisy BBs yesterday. I remember that one of you said he was sending them, but I don't remember who I am to thank. These will find their way into a vintage Daisy gun box somewhere.

This is actually my second look at BAM's B26-2. The first was back in 2006, when I tested a .22 caliber B26 with a standard stock. Today, I'll start looking at the same gun in .177, and this one sits in a thumbhole stock.

The B26 is BAM's second attempt at copying the Weihrauch HW95, which we all know as the Beeman R9. The B20 was their first try, and even that rifle was pretty impressive, but in the B26 has a copy of the Rekord trigger that was refined through more attention to finishing the parts.

For those who are not familiar with the R9, it's a classic breakbarrel spring-piston air rifle. It was developed from the BSF 55 action that Weihrauch acquired when they purchased the BSF company back at the end of the 1980s. The rifle went through several design iterations, first as the Marksman 55, then the Beeman R10 and finally becoming the R9. The R9 is a lightweight spring rifle with all the power of the Beeman R1 but at a lower weight and bulk. It has the famous Rekord trigger that gets airgunners so excited, so it was a natural to be copied.

I talked with the BAM representatives at the SHOT Show when the B26 first came out, which is how I know that the trigger was the major upgrade. They were really impressed with all the finishing Weihrauch put into the trigger, and they knew they would have to do more work if they really wanted to compete. That work was going to take their rifle from a retail price below $100 to significantly more, and in those days the Chinese competed on price, alone. So, BAM took a real leap of faith that the airgunning world was ready to pay more for a higher quality level. Of course, the fact that many were already buying the R9 helped them make the decision.

The rifle
The B26 thumbhole comes without sights, so plan on mounting a scope. The thumbhole stock is made from medium-brown wood that resembles beech. In typical Chinese fashion, the stock on my test rifle has several ares where wood putty was used to fill in gouges. There's no checkering, and the wood is finished very smooth. The raised cheekpiece is sharply defined around the border and looks very European. The butt drops very little, so medium or high mounts are what you want to use, because your cheek will already be quite high. Also, you might want to install an adjustable butt to lengthen the distance between your shoulder and cheek. Otherwise, the rifle will be difficult to fit to most people's hold.


Dark oval is wood putty. This rifle has three areas like this one. Most Chinese wood stocks will have this, though sometimes it isn't stained dark and can be harder to locate.

I have never been fond of thumbhole stocks because they don't fit my style of hold, but this one isn't that objectionable. It does make the rifle unfit for southpaws, however.

The metal is finished a little shinier than matte and is even all around. Markings are lasered on the metal, where they appear silver.


Rifle's nomenclature is lasered on the left side of the baseblock.

The trigger
BAM didn't copy the Rekord exactly and in so doing, they missed the boat. What you get is a delightful single-stage trigger with adjustable pull weight. If you can work with a single-stage trigger, this is a very good one. Light and relatively creep-free, but it isn't a Rekord.


A crisp single-stage trigger that's unlike a Rekord in operation. It still beats many popular sporting triggers found on air rifles today.

Dimensions
The rifle is 44.5" long and weighs a light 7.5 lbs. That's 1.5 lbs. less than an R1 of the equivalent power. The barrel is 16" long, but the muzzlebrake adds another 1.5" to that. The pull length is 14-1/8".

Cocking and trigger-pull
The rifle cocks at a surprisingly low 24 lbs. of force, which is amazing considering the advertised power. The piston seal is honking like a goose--a sure sign that things are too dry inside. That leads me to wonder if I shouldn't try to tune the rifle to see if I might knock off another pound of effort. The trigger lets go at 3 lbs., 2 oz. of pull. Because it's a single-stage, I don't want to adjust it too light or it could slip off by itself. The release is crisp and repeatable. And the safety, which is a weakness with Rekord triggers, is very crisp and positive. One negative observation is that the baseblock is under far too little tension. Once cocked, the barrel flops around freely instead of remaining in any position. A tune would fix that, as well.

A very nice air rifle
The B26 needs to make no apologies. It seems to hold its own with the R9. Apart from not having the Rekord trigger and the wood putty, the B26 is quite the air rifle--especially for less than $200. That's $300 less than the rifle it copies.