Design an Airgun contest, Part 2

Tom Gaylord
Writing as B.B. Pelletier

Part 1

This report covers:

  • Several entries
  • Norica bullpup
  • Nerf gun
  • Two great entries!
  • Maximus Blowhardus
  • Learned something
  • Spaghetti blowgun
  • Catapult gun
  • Without further ado, My plinker:
  • Some of the features I incorporated:
  • Penny shooter
  • The simplest entrant
  • Stonebow
  • Wow!
  • A hard job
  • Summary

Today we learn who is the winner of the Design an Airgun contest. It began on September 10 and was supposed to end at the end of the month, but several readers asked me to extend the closing, so I did. The contest ended last Friday, October 16.

Several entries

There were several entries. Some were blue sky dreams and nothing was built. I didn’t take them seriously. But some folks submitted more than one entry and they built all of theirs. I considered everything on the basis of the contest rules, which were:

1. I’m guessing it will be a BB gun, but it doesn’t have to be.
2. I’m guessing it will be a smoothbore, but again, it doesn’t have to be.
3. When I say build an airgun, it doesn’t have to work with compressed air.
4. It can be any kind of powerplant — so long as it doesn’t use an explosion to launch the missile.
5. The winner would be the niftiest design that the most people could build.

Now let’s see what people did. First is reader Jim.

Norica bullpup

This project was done back in the early 1980’s.  It started as a semi-finished Norica model 61 air rifle sold by Beeman.  The original kit consisted of an air rifle with an un-finished stock.  I suppose the idea was to capitalize on the popularity of unfinished muzzle loader rifle kits at the time. 

Norica right
Norica right.

Norica left
Norica left.

I had the opinion that the sight must be mounted to the barrel for accuracy, as opposed to the typical break barrel with the sight on the receiver.  Since this moved the sight forward, a bullpup design would place the eye closer to the sight.  It is interesting to see how popular bullpup designs have since become.

The stock is carved from several birch boards glued together.  Finding a location for the rear action screw drove the length, with locating it above the pistol grip.  The trigger transfer mechanism is steel, with lightening holes drilled to remove mass.  I had limited access to shop equipment at the time, so the construction is a bit crude.  The stock is Accraglass bedded to the action, again with the idea of improving accuracy.

Norica trigger
The Norica trigger was moved forward for the bullpup design.

The sight is an all-plastic ambient light red dot sight of unknown origin, but was cheap at the time.  An aluminum spacer raises it to eye level.

Norica sight
The sight uses ambient light, so no batteries are required.

Accuracy was very disappointing.  At the time, all I had were Beeman Silver Jet pellets.  The rifle has not been shot in years.  But knowing what I now know from the various articles of tests & tuning from master Gaylord, I may give this gun another try.

This is one of reader Jim’s first two submissions. It was submitted almost as a guest blog, so I decided to make it look like one. He clearly did a lot of work to this gun! Could anybody do it? Probably not. But we can all appreciate it!

Nerf gun

Submitted at the same time by Jim is this plan to build a Nerf gun.

Back in the early 1990s I built three Nerf® guns from PVC pipe.  This was before the huge proliferation of styles now available.  I tried to give the guns an ‘authentic’ look that would not be accepted in public.

Nerf gun
Homemade Nerf gun.

Now, having some shop access, I was able to turn the PVC parts and make the rest of the parts.  The barrel is several layers of hobby tubing soldered together to fit the dart and the PVC fitting.

Sights are strictly cosmetic.  Rear sights were salvaged from other air guns that were converted to scope use. The front sight is a brass blade soldered into a screw slot.

Nerf rear sight
Nerf gun rear sight.

Nerf front sight
Nerf gun front sight.

The piston head originally used a piece of urethane machined to provide a ‘parachute’ type seal.  However, like my FWB 124, the urethane eventually hardened and broke apart.  I added an O-ring seal instead, but never removed the remains of the original urethane.

Nerf piston
The Nerf gun piston.

I have yet to modify my other two pistols.  The spring is just a hardware store spring.  Parts are lubricated to increase velocity as much as possible.

The triggers are surplus M98 Mauser triggers I purchased from an advertiser in Shotgun News. The trigger mount is silver soldered to a steel tube to position the trigger to the sear.  Aluminum and brass collars center the tube to the external PVC body.

Nerf trigger attach
Here is a ’98 Mauser trigger attached to the steel tube of the Nerf gun.

The sear is a collar pinned to the piston/ cocking rod and is chamfered to allow the trigger to reset when the cocking rod is pulled back, it has been hardened to reduce wear.  Shown here is the relationship of the trigger to the sear.

Nerf sear
Here’s how the trigger interacts with the sear.

I added a spacer to the cocking rod to prevent the piston from slamming into the plastic PVC fitting when fired.  Several fittings were broken & remade before I limited the piston travel.  A couple of O-rings help to dampen the hard stop (shown on the handle that’s pulled out on the rear sight photo).  The grip is bent square brass stock with walnut grips cut to fit — also shown on that photo.

The finned Nerf darts sail quite nicely, and will fly about 40 feet.  My daughters were in high school at the time, and these were very popular when they had friends over.

Two great entries!

These were two great entries. Unfortunately they were submitted in Microsoft Word format that contains all sorts of embedded code, so they took me many hours to sort out and strip off the code that couldn’t be used. Plus the photos were embedded in the document, which means they had to be pulled out and reformatted. Most word processing programs are not friendly to online publishing software. If you want to submit a guest blog, please ask me because I have to give you some submission guidelines first.

Jim also sent a great submission of a pedestal-mounted potato gun cannon. It’s even more complex than the first two, and I am saving it as a guest blog of its own, if I can get Jim’s permission. But here is a picture of it.

potato cannon
Reader Jim also gave us a potato cannon submission that I hope you will read about in the future.

Maximus Blowhardus

Reader pacoinohio whom I once jokingly called Pinocchio (and I heard about that from many readers!), sent us his submission that he calls Maximus Blowhardus.

Well I’ve been thinking about my entry. What to do? What to do? They say you should play to your strengths. I am after all a plumber. Not really, but I do know The Prime Rules of Plumbing — Water runs downhill; you get paid on Friday; don’t pick your nose on the job. 

So, here is my gun plumber entry that I call—

Maximus Blowhardus
Maximus Blowhardus.

It is simple pieces of black iron pipe, a couple of brass ball valves and some PVC bits.

Design criteria began with caliber selection which was dependent on projectile availability. Found a bag of wine corks that seemed suitable, so I settled on 1” pvc. Power supply? Oh yeah, air compressor in the shop. That helped with the rest of the parts selection. 

Took about 20 minutes at the big box store to get everything and another 20 minutes of assembly. Hooked up the air hose. Compressor is regulated at a modest 100 psi. Inserted a cork in the barrel, filled the reservoir and then attempted to fire. Stress ‘attempted’. The cork did not fly. Too much air passing by. Paper patching to the rescue.

I wrapped the cork with paper towel (Brawny for those taking notes) for a moderately snug fit in the bore. Second shot went about 25’. Hmmmmm……. what if I dampened the paper patch? This allowed for a tighter wrap and resulted in a 30’ distance. It also revealed that the bore was filthy. Yeah, I reused a piece of PVC. Important lesson — Always clean the bore. Brief break to do that and then back to testing. 

Up to this point, I had been using both valves. Fill reservoir, shut off fill valve, then open discharge valve. On the next shot, I did not close the fill valve and just opened the discharge valve. Almost 90’ distance. Enough. 

I think I have achieved proof of concept. Low pressure requires a large volume of discharge air. On the last shot I had added the air compressor tank and air line volume. So next step is to reduce caliber of bore. I think I will go with 1/2” and continue firing tethered for maximum air. I will have to turn the corks to size. Toying with using o-rings to seal to the bore. Lots of options of size, material, durometer, etc. And then there is lube. Have to polish the bore of the new barrel. So many rabbit holes. 

Learned something

Well, we learned something from Paco’s submission. If you are going to shoot with low air pressure, you need plenty of it. One-hundred pounds per square inch may sound like a lot, but to airgunners it’s definitely low pressure!

Spaghetti blowgun

Reader minuteofsomething made an unusual submission in the form of a You Tube video. Let’s watch.

Now, I have to say, this one is so simple even old BB could do it! And he shot it to some distance that I will guess was 15-20 feet. So it doesn’t just shoot through cans, it shoots to a good distance.

Catapult gun

This one comes from reader Airman of the Board

I present for you my entry into BB’s Airgun Design Challenge. It is a single shot rubber band powered catapult gun (capable of launching BBs as well as other appropriate projectiles of your choice) built from what I had around the house.

First, however, I would like to thank BB for having this contest. It motivated me to spend a lot of time in the shop this last week week and a half. Burning the midnight oil, as it were, solving design puzzles and trying new techniques. I am excited to show you all what I made. But first a few words about what I was trying to accomplish with my design.

As a long time reader, but first time poster, I hope I am not “oversharing” with this long post. I put a lot of effort (>40 hours) into this project and I am hoping it is something you all might be interested in.

BB said,”The winner would be the niftiest design that the most people could build.”

So that the most people could build it, I wanted my design to be low risk. A project for people with limited tool use and fabrication experience. A design were if something were to go wrong during the build or with the final product, the gun would not be subject to catastrophic failure, thereby unleashing a lot of pent up energy. Perhaps other novice airgun builders would be like me and find the complexities of starting to work with high pressure air, or controlling the power of a high strength spring intimidating. The design should also favor simple parts that don’t require tight tolerances and complex machining.

I do not wish to presume BB’s intention behind this design challenge, but I speculate it was to offer people the satisfaction of making something for themselves, and participating in a new facet of a hobby that fascinates us. It was not, I imagine, an attempt to uncover an airgun engineering savant among us. As amateur airgun designers we are unlikely to best the professional engineers working in this field. This suggests that this challenge was not about making the most refined, powerful or elegant design, but rather something that offers the individual the satisfaction of making something from scratch, the use of which would provide that other joy of man: launching projectiles. A plinker, that he or she made.

Without further ado, My plinker:

Drawing obvious inspiration from the Sharpshooter catapult guns that BB has featured on this blog, this “airgun” is a single shot rubber band powered launcher that I believe could be made various ways with relatively few tools. I made every piece of the prototype from readily available raw materials. The only parts I didn’t make were the screws, a coil spring scavenged from a retractable pen, a small magnet, and the rubber bands. I finished the project about an hour before I wrote this, so there has only been preliminary testing. I have not tried to tweak the performance, but think it is fair to say it will not satisfy the airgun connoisseurs desire for precision long range shooting equipment, but it will hit the broad side of a barn (I have been able to repeatedly hit a can at five paces). The piece favors an artillery hold. I don’t know how lightly it likes to be held, but you better point it up if you want any distance. I would rather get hit by the pea than the pea shooter, if you catch my drift.

The heart of the design is a cylindrical bolt in a slotted tube. The bolt is attached to the tube by means of elastic bands, which drive the bolt forward to propel the shot. The bolt face has a conical recess to accept and center the BB. The design could be made as simple or nifty as you desire. Simple: tying rubber bands to a PVC tube with a wooden dowel bolt that has another wooden dowel running perpendicular through it. The slot in the PVC could take a right angle dog leg at the rear to act as a bolt catch and rudimentary trigger. Or you could build it as I have here. What additional features and style you add to the basic premise depend on your abilities and desire for “niftiness”. Because I assumed the purpose of building one’s own airgun to be the pride of ownership and satisfaction of having made something, I saw no reason not to make as many parts as I could, and spend the extra time to make it nifty.

Some of the features I incorporated:

  • Figured Maple stock with checkered walnut grip panels.
  • Cold blued steel main tube and bolt
  • Adjustable (for sear engagement) trigger with steel sear pin (pictures upon request)
  • Aluminum trigger and “sear bar” (bar under main tube)
  • Magnetic bolt face to retain steel shot.
  • And to help the marketing men:
  • Free floating barrel
  • Polished Aluminum main tube end caps (barrel shroud?)
  • I think it has a Buck Rogers on the American frontier– ray gun meets Kentucky long rifle vibe.

Thanks for checking it out. Let me know if you want more pictures.
Now to go clean up the shop…..

A picture is worth a thousand words:

catapult gun
The AOB catapult gun.

catapult gun
Different view.

catapult gun materials

catapult gun parts
Catapult gun parts.

That entry is one after my own heart! I have always wanted to test a Hodges catapult gun and Airman of the Board has shown us how to make one! Of course his pistol plans would need to be scaled up to make a long gun, but it’s all there.

I also think this is the beautifulest entry of the contest!

Penny shooter

Airman of the Board also submitted a design for another catapult gun that’s a coin shooter. It’s similar in function if not design to the Turnpike Toll Gun I reported on in 2013.

I present, for your consideration, another entry into BB’s Airgun “as long as it shoots something at a target” Design Contest – The Penny Arcade Shooter.

penny shooter
The penny shooter.

penny shooter cocked
Penny shooter cocked.

What we have here is a catapult-style penny-shooting three-shot derringer. Three cents can be loaded into the “magazine” cutout on top, and each in turn is automatically loaded into the chamber/ barrel as the charging handle is pulled back. It has a spring-loaded penny catch and trigger mechanism, straight blade brass trigger, and open sights. It is made from Red Oak, .125” brass rod, some thin plywood (.15”), a small bit of music wire, and rubber bands.

penny shooter parts
Penny shooter parts side view.

penny shooter parts 2
Top view of the parts.

The design could be built with only the most basic woodworking tools, and the materials could be altered to what is on hand/ available. (Paint stirrers, popsicle sticks, small nails and pen spring?) The design could be scaled to the denomination… ahem..caliber of your choice. Ammunition is likely already on hand, and is cheap, especially since it can be reused.

I built it in a day, along with an arcade (cardboard box with rod running through it from which 3D targets are suspended) that my partner and I got a kick out of using indoors that evening. She got the hang of it quickly and was hitting a 4” target at 5 meters.

One could even just build the barrel and plunger mechanism and use rubber bands to manually shoot coins. But, if you want my two cents, (which is over half of this gun’s basic load – ED.) it is worth building the handle and trigger mechanism. It does not have to be that precise. Just as the act of marksmanship brings with it the joy of seeing your sphere of influence projected beyond the direct reach of your hands. A similar enjoyment can be experienced with the construction and use of a mechanism by which you touch/ act upon one thing and the effect takes place upon something else. Go on, get your Rube Goldberg on.

Thanks for checking it out. I welcome any comments or suggestions.

I like it! Everyone wants a Toll Both Gun but they are prohibitively expensive. This one you can make for very little money. 

The simplest entrant

So far we have seen entries that require some skill and a lot of work — except for the spaghetti shooter. Now we come to another entry that vies for the position of the simplest one. It’s called Smile from reader Fish.

Here is my entry to the AG Design Challenge. It’s called Smile. Shoots cotton swabs. Anybody can built it under $1.50. Fish.

It comes with no instructions, but it doesn’t really need them.


From the frozen north of Canada, reader Vana2 who is our friend Hank, sent us his  stone crossbow that he calls the Stone X-Bow.

For the “Design an Airgun” contest for something that shoots I would like to submit a “Stone X-Bow” which as the name implies, is designed to shoot stones or better still, marbles or ball-bearings instead of bolts.

Stone X-Bow
The Stone X-Bow is a modern interpretation of the ancient stonebow.

I have always loved anything that shoots a projectile and in my early teens designed and made a whole variety of weapons powered by elastics or bows. Slingshots were great but back then the bands (usually cut from bicycle inner tubes) were nowhere as good as the latex and surgical tubing bands used these days. Considering power and availability, bows were my power-plant of choice, the following is a prime example…

The overall Stone X-Bow design is straightforward and can pretty well be laid out on the fly. The main considerations are to have at least a 2.75 inch “window” between the bows and the bow supports (to clear the projectile) and to be sure that the pellet pouch is centered between the bows. The bow’s draw length determines the distance from the bow supports to the release mechanism. The rest of the stock can be penciled in to suit, with the only requirement being the shape of the grip for the trigger.

A variety of material can be used to make the bows. The bows for this project are cut from a fiberglass chain-link fence “tensioning bar”. Fiberglass rods used as driveway markers, or tent poles or chimney cleaning poles are suitable as well. Bamboo stakes also make a good bow, you just have to match up a pair and join them in the middle.

The Stone X-Bow is a fun project that is inexpensive to build and can be made with a couple of hours effort (spread over a day or two to allow for glue setting). They are consistent shooters and can be made powerful enough for small game hunting. In pursuit of “how big can you make it” I made a Stone X-Bow that would rival a potato cannon in power. It shot golf balls.

Hope you find this interesting enough to build your own.

To eliminate complex routing I laminate up the stock from six 6 inch wide, 1/4 inch thick pieces of plywood. Per the picture below, two pieces marked “A” are the outer laminates; “B” are the laminates that provide the clearance for the trigger block and “C” creates the slot for the trigger.

Stone X-Bow laminations
Quarter-inch laminations saved the problem of routing thick wood with precision.

Labeling all the pieces and pinning them together (with 2 inch finishing nails) keeps everything together and aligned for cutting and later registered for gluing.

I didn’t have any plywood available so I cut my 1/4” material from a 2×4 and added a piece of 2×6 for the butt of the stock. Not having the plywood was a bit inconvenient but it can be made to work without too much problem.

The trigger of the Stone X-Bow is a rolling block style similar to that found on many regular crossbows, the difference is that it has a single pin to capture the pouch rather than two pins to hold the string and bolt.

Stone X-Bow trigger detail
Trigger assembly detail.

Stone X-Bow trigger sear
The trigger sear.

Stone X-Bow fired
The trigger has fired the bow.

Stone X-Bow from the top
Stone X-Bow from the top.

The trigger block is made from a piece of hardwood dowel and a bolt that is long enough to make the pin and has the head filed flat to make a sear. The trigger block is mounted with two screws that are supported by washers imbedded in the stock.

The trigger has another modified bolt and is positioned to engage the sear on the block. A spring is used to keep the sear and trigger engaged until the trigger is pressed. I used a 2-inch finishing nail for the trigger pivot point.


Hank has just given us the detailed plans for a stonebow. Only a little more work is needed to turn his design into a crossbow. This is not the simplest project by any means, but it is one of the best!

Hank is aware that he cannot win the prize that would be difficult to receive in his country. He just wanted to be in the contest to support the blog and all of you readers. Thanks, Hank!

A hard job

When I started this contest I didn’t anticipate there would be this many entrants or this many really good projects. What we have is a range of projects to appeal to skills of all levels. I believe that many of you 100,000+ registered readers, as well as the quarter-million or more around the world who just read the blog and haven’t registered, are going to get much more from this contest than from several of my reviews put together.

How did I judge the contest? It wasn’t easy. In the beginning I wanted to make each new entry the winner and all I had to do was decide which of their projects I liked the best. But as more entries were received, things became more difficult. But one rule probably superseded all the others, and that was rule 5 that said, “The winner would be the niftiest design that the most people could build.” That made it easier for me.

While all of these entrants deserve recognition, one of them stands apart, based on rule 5. The winner of the Design an Airgun contest and the recipient of the American Zimmerstutzen — providing he still lives in the U.S.A. — is reader minuteofsomething, whose spaghetti blowgun is the niftiest and simplest project I see.

I purposely have not informed him of this. He gets to learn about it with the rest of you, by reading this report. I do have his email address but I am asking him to contact me today.

He has a You Tube channel with many other interesting videos, and I will try to make that available to all of you, once we connect.


This contest has opened my old eyes about what interests many of you readers. I wish my late wife, Edith, had been here to see it, but I believe she may be following it anyway. My thanks to all of you readers for a most enjoyable time — Tom

Umarex Air Javelin airbow: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Umarex Air Javelin
The Air Javelin from Umarex.

Part 1
Part 2
Part 3
Part 4

This report covers:

  • Quick review
  • More arrows
  • Setup
  • Sight in
  • At 10 meters
  • At 20 meters
  • Raise the sight
  • Summary

Today I shoot the Umarex Air Javelin at 20 meters with a dot sight that has been sighted in. You finally get to see the sort of accuracy that I saw at the SHOT Show in January. The range there was set up for about 25 yards and it seemed like the arrows all went to nearly the same place! You will see that today.

Quick review

Part 4 was a test with a dot sight too, but I also tested the Umarex CO2 adaptor that allows you to use two 12-gram CO2 cartridges. Unfortunately the Tasco Pro Point dot sight I used for that test could not achieve the elevation that was needed to hit the target at 20 meters. I also shot wide of the target bag when I shot an arrow that had been damaged in the rear from a Robin Hood. I didn’t know it was damaged until I pulled it from the fence and examined its base.

The adaptor only gave me 8 powerful shots. A reader told me that he gets 12 powerful shots. He asked me to check the ends of both cartridges to make sure both had been pierced. I did and both had been pierced for sure. I learned years ago when using multiple CO2 cartridges to back off on the piercing screw to allow the gas to push the bottom cartridge up away from the piercing pin and flow better. 

The same reader also said that the holes in the CO2 cap are to allow the gas to exhaust the end of the run, and indeed that is correct. However, I discovered that the adaptor was stuck in the gun after shooting until I inserted an Allen wrench into one of the holes to break it free — so what I said about using the hole for that purpose also applies.

More arrows

In Part 4 I lost one of the three arrows that came with the AJ and a second one was damaged by another arrow hitting its rear in a Robin Hood shot. So I emailed Umarex and asked for a couple more arrows to continue testing and by the end of the week they had sent me six. Those arrows made today’s test possible. With the one arrow I have that gives me 7 to test.


For this test I installed a fresh 88-gram CO2 cartridge in the AJ. I didn’t want anything to spoil the test. I also switched from the Tasco Pro Point red dot sight to a UTG Reflex Micro green dot. I knew from experience that this sight has a wide range of adjustments, which the AJ I’m testing needs.

Air Javelin UTG dot
I mounted the UTG Reflex Micro Dot sight forward on the AJ.

Sight in

I learned a valuable lesson last time. Always sight the AJ in at close range after installing an optical sight, or you may miss the target bag altogether. This time I started at 5 meters. The arrow hit high enough but to the left of the bull. I adjusted the sight to the right for the second shot and it  landed inside the bull about an inch away at the same height. That was enough for me, so I took the target bag out to 10 meters and shot again.

At 10 meters

This time the arrow landed at the bottom center of the bull. A second shot hit next to the first one. Neither arrow was damaged, bit I learned that 10 meters is too close to sight in. We don’t mind pellets going into the same holes when we shoot, but with arrows it’s a completely different story.

Maybe the lesson should be expanded to pull each arrow as it’s shot when you are sighting in.  The centers of these two arrows are 1/2-inch apart. But I didn’t pull them out of the bag.

Air Javelin sight 10m
From 10 meters the Air Javelin put two arrows within a half-inch of each other.

At 20 meters

Now I moved the target bag out to 20 meters and fired again. This time the arrow hit about an inch and a half lower and maybe an inch to the right of the two shots at 10 meters. I left all three of these arrows in the bag., I expected the arrow to drop at 20 meters, but the sight should be able to compensate for it.

Raise the sight

I adjusted the UTG Reflex Micro dot sight up by 11 clicks. I didn’t know exactly what that would do at 20 meters, but I do know that the clicks move the point of impact quickly with this sight.

The first shot hit inside the bull and slightly above the centerline. It was almost straight up from the previous arrow that had been fired. Through dumb luck I had adjusted the sight up by the correct amount. I bow hoped to shoot a group of several arrows for you, but then a bad thing happened.

The second shot at 20 meters was a Robin Hood that damaged the back of the arrow shot just before. Okay — even 20 meters is too close to shoot the AJ without pulling the arrows after every shot! I need to move the target bag out to at least 35 yards before I test the Air Javelin again. And, I am writing this reminder to myself for that test. Put three clicks of left adjustment into the sight and then pull each arrow as it is shot at 35-40 yards!

Air Javelin 20m
Here are all the arrows shot at 10 and 20 meters. Even with the sight adjustments and the different distances , the centers of these arrows are just 3-inches apart.

Air Javelin target
This is the target paper with all the arrows removed. The two holes on the left are the 5-meter sight-in. The two holes at the bottom of the bull were the next two that were shot at 10 meters. The bag went out to 20 meters and then I shot the lowest hole on the target. The sight then went up by 11 clicks and I shot shot the two holes at the top right at 20 meters.

Rather than waste arrows I plan to shoot another test at a longer distance. I will probably also pull the arrows as I go. 


I now have 6 good arrows left — one of the three that came with the AJ and five of the six that Umarex sent me to continue this test. It’s obvious that I have to be very careful because the AJ wants to put all the arrows into the same place. This accuracy is very equivalent to what we saw with the Sub-1 crossbow at close range. But the AJ is well over a thousand dollars cheaper.

Umarex Air Javelin airbow: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Umarex Air JavelinThe Air Javelin from Umarex.

Part 1
Part 2
Part 3

This report covers:

  • More to test
  • What are the holes for?
  • Remove the old 88-gram cartridge
  • Lots of gas!
  • Install the adaptor
  • Cock the gun!
  • Don’t do as BB does!
  • Adjust the dot sight up
  • Discussion
  • Summary

Today I shoot the Umarex Air Javelin with a dot sight optic. My UTG Reflex Micro  Dot was mounted elsewhere so I mounted a Tasco Pro Point red dot sight. 

Air Javelin dot sight
The Air Javelin accepted the Tasco Pro Point without a problem.

More to test

I didn’t tell you this but I asked Umarex to send me a 12-gram CO2 adapter so I could test the AJ with 12-gram cartridges. Some readers had asked about that possibility and since Pyramyd Air doesn’t carry the adapter, I went straight to Umarex.

Air Javelin 12-gram adapter
Several Umarex airguns including the Air Javelin use this adapter that switches the power source from 88/90-gram CO2 cartridges to 12-gram cartridges.

Let’s look at how it works. One end has an end cap that unscrews to accept the two 12-gram cartridges. The other end is treaded to screw into whatever airgun you install it on.

Air Javelin adapter description
The adapter has an end cap (arrow) that comes off to insert the CO2 cartridges, and threads on the other end to screw into the airgun. The holes are for moving the end cap when pressure holds it tight.

The two cartridges go into the adapter nose to nose. The piercing end of the first cartridge goes in first and the piercing end (small flat end) of the second cartridge is left up at the top, where the pin in the cap can pierce it. There is a spring-loaded winding tab on the cap. The spring holds the tab flat against the cap until you need it.

Air Javelin adapter cap off
The adapter cap has been unscrewed.

No directions for use came with the adaptor but it is pretty easy to figure out. I unscrewed the end cap piercing screw as far as it would go before dropping two cartridges inside. And I dropped in 5 drops of Crosman Pellgunoil before inserting the first cartridge. Then I put more Pellgunoil on the tip of the second cartridge.

Air Javelin cap screw
Here you see the cap screw (bottom) unscrewed as far as it will go.

What are the holes for?

If you ask what the holes in the sides of the end cap are for you haven’t yet encountered a gas gun with so much pressure that it wouldn’t let go of the end cap. This used to be a real problem in the 1950s and ’60s when improper o-ring material would swell from the gas and no let go of the end cap for hours after the gun was empty. With modern materials there is no more problem, unless the gas pressure inside the adapter is still high. This is not a large problem; it’s more of a convenience.

As you can see, I unscrew the piercing screw on the end cap as far as it will go, then screw the end cap down as far as it will go. Now I pick up the spring-loaded tab and start screwing the piercing screw in. That one screw is piercing both cartridges. It pushes the bottom cartridge down on the internal piercing pin inside the adapter as well as screwing in the piercing pin in the end cap. So I run it in as far as it will go. I heard no gas escape when I did this, but just to make certain the piercing pins were out of the way of the gas, I unscrewed the tab about a turn.

Remove the old 88-gram cartridge

Before the adaptor could be installed I first had to remove the previous 88-gram CO2 cartridge that was in the AJ. I didn’t know for sure but I calculated there were around 20 shots on it. We learned in Part 1 that the AJ has up to 30 good shots on one 88-gram cartridge. The last shots will send arrows out at just under 200 f.p.s. while the first shots have them going over 300 f.p.s. I will have more to tell you and show you later in this report, but for now you need to know that I was removing a cartridge that had a good 10 shots remaining inside. I had to do it to get a shot count from the two 12-gram CO2 cartridges in the adapter I’m about to install.

Lots of gas!

I will say this. Once you slowly unscrew the CO2 cartridge it comes to a point when the remaining gas is no longer sealed and starts hissing out. That lasted a long time — several minutes at least. I also dry-fired the AJ about 10 times as it was loosing gas to speed up the process. In the end the last gas hissed out and the old cartridge could be removed. The gun was now ready for the adapter.

Install the adaptor

The adaptor just screws into the gun where the CO2 tank was. Remember I put Pellgunoil inside when the cartridges were pierced, so that gets blown into the AJ to get on all the internal seals. BUT…!

Cock the gun!

Umarex tells you not to cock the gun when installing a new cartridge and I expect they also mean this adaptor. That is obviously a safety issue. But the adaptor holds two 12-gram cartridges that have limited gas. So I screwed the adaptor in, and when the hissing began I cocked the AJ and stopped it instantly.

Air Javelin adapter in
The adaptor fits in the AJ just like an 88-gram CO2 cartridge. This photo was very important later in the test!

Don’t do as BB does!

This is an object lesson. Some of you think I am modest, but the truth is — I am often that bad example your mother warned you not to follow! I set up the target bag in my back yard about 10 meters from the shooting bench. Yes that’s pretty far but I hadn’t shot the AJ in two months and my last recollection was one of great accuracy. It really was accurate last time — what could go wrong? I held the red dot in the center of the target that was taped to the bag and fired the first arrow. But I couldn’t tell where it went. It wasn’t anywhere on the bag! Oh, oh!

I looked in the grass all around and under the bag for signs of the arrow and then in the wooden fence between my property and my neighbors. Nothing. So I dragged the bag back to 5 meters and shot again. This is where I should have placed the bag to begin with.

Adjust the dot sight up

This time the arrow hit the bag, just below the bottom of the target paper. My previous shot had been taken at twice the distance, so the lost arrow is definitely somewhere in my lawn at something less than 10 meters. I searched for another 10 minutes for that first arrow with no luck. Umarex had only sent me three arrows with the AJ, and now I was down to just two. I adjusted the elevation up considerably and shot again.

Shot three hit a half-inch or less from shot two. It was on the bag but still below the target paper. From the looks of it (it was on an angle in the bag), it may well have hit the back of the second arrow— something I would discover in a little bit. Now I knew I was on the target so I cranked in a whole lot more elevation and moved the bag out to 15 meters.

Then I let fly with shot number four. This time the arrow hit the bottom of the 6-ring, almost touching the bullseye at 6 o’clock. Wow! I pulled the arrow out and moved the target bag out to 20 meters.

That shot had looked so good that I fired my second shot (number five on the CO2 adaptor). It hit the target about 3/4-inches below the last one. I needed to watch out or I would Robin Hood my two remaining arrows.

The last test in Part 3 demonstrated that the AJ is very accurate at this distance, so I felt confident it would not be a problem. However — remember that arrow that may have been hit in the back? I knew that I would nail the target in line with the center of the target and with luck I’d be inside the bull. No such luck! This time I heard a sickening sound of the arrow hitting the fence behind the bag. I have never missed the bag before this shot and was surprised I missed it this time. I found the arrow that had gone 4 feet wide to the left and was halfway through the fence.

When I pulled that arrow out of the fence I examined it to see why it had gone so wide. Right away I saw it. The end of the arrow is blown out on one side. I think I did hit the back of this arrow earlier and now I was rewarded with a wild shot. When I enlarged the pictures of all three arrows that was taken before the test started I saw that none were damaged this way. That is what I meant by that earlier picture being so fortuitous.

Air Javelin arrow end
The end of the AJ arrow that went so wide at 20 yards was broken out on one side — causing the arrow to veer to the side as it came off the end of the air tube. This arrow was probably hit in the rear on shot number three.

Air Javelin arrows
I enhanced this earlier photo to show there was no damage to any of the three arrows at the start of this test.

For safety’s sake I moved the target bag back to 15 meters and fired my one remaining arrow three more times — shots 7, 8 and 9. Shot 7 hit the target at the bottom center of the largest ring in the white. I had to pull the arrow to shoot shot 8 and it hit the target about 3/4-inches below and to the right of shot 7. On this shot I noticed a lot of time between the shot and the arrow hitting the bag.

Air Javelin arrows shot 8
Shot 8 at 15 meters hit below and to the right of shot 7. I could hear that this arrow was slower.

I pulled the arrow and fired one more time. This time there was a definite slowing of the arrow and it hit at the bottom of the paper, a little more than an inch below shot 8.

Air Javelin arrows shot 9
Shot 9 hit the target a little more than an inch below shot 8.


Based on this test I can say that two 12-gram CO2 cartridges give you about 8 good shots. They are not all the same speed, but I believe they all fall within the velocity spread of the 30 good shots you get from an 88-gram cartridge. Analyzing the costs tells me you get 8 good shots for about $1.00 with two 12-gram cartridges, and 30 good shots for about $8.00 with one 88-gram cartridge. The advantage of the adapter is shots that cost less. The advantage of the 88-gram cartridge is a lot more shots per cartridge. The velocity of the shots is the same because CO2 varies its pressure due to temperature. Volume is not a factor in pressure.There is no easy way to increase or decrease that pressure — certainly not one that’s available to the field.

The second thing I would tell you is to always examine your arrows just before loading them. I didn’t and only through a fortunate photograph was I able to determine that an arrow had been damaged during this test. A damaged arrow flies erratically and is too risky to shoot.

One last comment is that I need to jack up the rear of the dot sight for the next test. I had to apply too much elevation to get the arrows near to the aim point.


I’m still very impressed by the Air Javelin. Even with the challenges of today’s test, which in retrospect were all mine, the AJ held its own. When it is given half a chance it places its arrows close together at the distances I have been testing.

The CO2 adapter performs as well as many expected. I was surprised by the number of good shots we got in today’s test. And it is very easy to set up and use.

Hopefully we will see the AJ at least once more, and this time with more arrows and no sighting problems.

Sen-X AR-6 Tactical Arrow Repeating Crossbow: Part 3

by Tom Gaylord
Writing as B.B. Pelletier-

Sen-X AR-6
Sen_X AR-6 Tactical Arrow Repeating Crossbow.

Part 1
Part 2

This report covers:

  • Sights
  • Dot sight
  • Vibration
  • Safety
  • Hunting limb
  • Sight-in
  • Group
  • Damage to one arrow
  • Stopped at this point
  • Observations
  • Fletching
  • Next test
  • Summary

Wow! It has taken me a looooong time to return to the Sen-X AR-6 Tactical Arrow Repeating Crossbow. Most of the reason for the delay was the weather that never quite cooperated, but when I tried to do a test at the end of February the problem became something else altogether.


In Part 2 I showed you that the sights on the bow are primitive. There is a front post, but in the rear there is nothing to align it with except the silver spring latch on the magazine cover. There is a red laser built into the AR-6, but it cannot be seen in daylight beyond about 10 feet. With just those crude sights I managed to shoot the bow fairly well, but I wondered what better sights would do.

Dot sight

The sight I selected for the AR-6 was the UTG Reflex Micro dot. Pyramyd Air sells the red one but I have a green one that I use because a green dot is easier for me to see. The crossbow has a Picatinny rail on the front where this sight fits easily. I picked this sight for its small size. It seems to be made for this crossbow. I thought to have it sighted in within a few shots.

The UTG Reflex Micro Dot sight is perfectly sized to fit the AR-6 crossbow.

I sighted-in the dot sight at about 12-15 feet. Once the dot was doing well there I backed up to 10 meters and shot a magazine’s worth of confirmation shots. Then I backed up to what I now know is 18 meters.

At 18 meters the crossbow hit fairly well on the point of aim. Two arrows went together pretty close. But on the third shot I missed the arrow stop/bag altogether — something I had not done in all my previous testing of three crossbows, plus an Air Venturi Wing Shot air shotgun firing Air Venturi Air Bolts. All of that put over 200 shots into that bag! I heard the AR-6 arrow hit the fence behind the bag. It did not stick in the cedar wood of the fence slat, but bounced off and landed on the lawn. When I examined the arrow I could see it had bent from the force of the impact.

The metal shaft of the arrow bent from impact.

How could I have missed a target that had seemed so easy so many times before? Was the dot sight loose? I grabbed it and shook it and it was still mounted solid. But the bow limb wasn’t! It wobbled and slid in its slot, which it’s not supposed to do. If you recall in Part 1 I told you that I had to assemble the AR-6 before I could shoot it . The bow limb (what many would call the bow) had to be secured to the bow deck with a large Allen screw.

A large Allen screw holds the bow limb tight to the bow deck.

This fault came up suddenly and unexpectedly, though I imagine there were signs beforehand, if I had been looking for them. But now the bow limb was moving around like I knew it wasn’t supposed to and I remembered there being some steel shims in front of and behind the limb where the Allen screw contacted. I found the shims on the ground where I was shooting.


The AR-6 is a completely mechanical contrivance. Every time it fires the bow limb springs forward as far as the bowstring will permit and then stops suddenly, sending vibration throughout the entire assembly. I did not appreciate that. I know that spring piston airguns vibrate, but crossbows vibrate, too. And they need the same attention to tightening their screws as do springers — especially this large one that holds the bow limb in place.

At first I was concerned that I might not get the limb back into perfect alignment. Then I remembered that I had assembled it only a few weeks before and the process is very straightforward. There are marks and guidelines on the limb and the deck to assist you.


A bigger concern for me was safety. I had never missed the arrow bag/trap before, in spite of testing numerous crossbows and arrow shooters. Two people I allowed to shoot my Sub-1 crossbow and the Wing Shot had missed the bag, but I found out afterward that neither of them understood how they should be aiming them. It’s funny how they won’t tell you beforehand that they don’t understand what you have told them to do, but after the shot goes bad they open up!

Now, I was the one who wondered whether I knew how to shoot the thing. Sure I got it together again and it seemed tight, but I had also done that before, when I assembled it out of the box the first time. Oh, woe is me! And then the hunting limb arrived from Pyramyd Air!

Hunting limb

The hunting limb increases the power of the AR-6 to about 12 foot-pounds. That doesn’t sound like much until you consider that the target limb I am testing produces a little over 8 foot pounds (8.31 foot-pounds, according to the description on the website). Then you realize the hunting limb boosts the power by almost 50 percent. Here I am languishing in fear of the target bow and there is still a more powerful bow to test. Buck up, BB. Time to get with it!

Well, weather and equipment issues slowed me down again until last Friday. Then I got a perfect day to shoot and took full advantage of it.


I sighted-in the dot sight again, since I had to remount the bow limb. Again I shot from 12-15 feet, then 10 meters and finally from the same 18 meters as before. When I was finished the bow was shooting to the point of aim at 18 meters.

I had used the same arrows for all earlier shooting, as well as sighting-in this time. The fletching on those arrows was pretty much gone.

The same arrows, shot perhaps 15-20 times each, had lost much of their fletching.

So, I decided to use 4 new arrows to shoot at 18 meters. Would they shoot to the same place as the arrows I used for sight-in? Only one way to find out! Watch the video.


Three arrows went into 2.552-inches at 18 meters. The fourth arrow opened the group to 3.827-inches. All of this was shot offhand, as you saw in the video.

Damage to one arrow

The arrows sank deep into the target bag. The first shot went in beyond the beginning of the fletching and peeled back both synthetic “feathers” of either side of the arrow. I think there are now so many holes in the target bag that the smaller AR-6 arrows have an easier time sinking in.

AR-6-fletching damaged
This new arrow sank into the target bag deep enough to peel back the synthetic fletching on the first shot.

Stopped at this point

I ended the test at this point. Though the film shows only the final 4 shots, I shot about 15 other times to get the crossbow sighted in. At this point in this series I have made several observations.


The new arrows shot to a lower point than the ones with damaged fletching. I need to correct the dot sight to account for that.

The fletching on the arrows is subject to damage from penetrating the target bag too deeply. I now have many straight arrow shafts that are in need of repair. I will also look for ways to mitigate the damage, if possible.

The new arrows hit lower on target than the old arrows with damaged fletching. This is possibly because the full fletching creates higher drag on each arrow. I should shoot this bow again and adjust for the new arrows.

After 19 shots the Allen screw is still tight and the bow limb is still locked in place. I need to continue to check that from now on.


The word fletching means feathers, which were used on arrows in times past to create high drag and spin. The synthetic fletchings found on the AR-6 are called vanes and are sold by many places, along with the glue to hold them to the arrow shaft. This is something I need to research so I can repair my damaged arrows. I will tell you about it as I go.

Next test

I plan to shoot the bow again with fresh new arrows and adjust the dot sight to hit with them. I believe I can shoot 5 arrows offhand into a group smaller than three inches from 18 meters. That will be the completion of my sight-in with the dot sight.

After that I plan to switch the bow limb to the hunting limb that also came with a new bowstring. Then I will run the same tests that I have with this bow limb, except I will start with the dot sight mounted.


I did discover that my AR-6  works fine with 5 arrows or less in the magazine, but if I load a 6th arrow that it is supposed to work with, it malfunctions. That was probably my fault, because I accidentally bent the magazine spring that holds the arrows down and feeds them, when I closed the mag cover with the spring not inside. I could probably fix it but I don’t mind using it as is, and it does work just fine with 5 arrows.

The AR-6 crossbow pistol is a blast to shoot. It is to crossbows what the Diana 27 is the pellet rifles. There are many that are more powerful, but none that are more fun. I don’t think it has to justify itself by being a hunting arm. Can’t something exist just for the fun of shooting?

Umarex Air Javelin airbow: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

The Air Javelin from Umarex.

Part 1
Part 2

This report covers:

  • Before we begin — the inside diameter of the gas tube
  • The test
  • Setup
  • First shot
  • Aiming
  • Loading
  • Shot away!
  • Move target to 11 meters
  • Shot two
  • Shot three from 10 meters
  • Back up to 17 meters
  • Adjusted the rear sight one last time
  • Shots 5 and 6
  • End of the test
  • Shots 7 and 8
  • Summary

Today I shoot the Umarex Air Javelin airbow for accuracy. I know that a lot of readers have been waiting for this! This will be an accuracy test, but as I said before, the AJ is such an important shooter that this report is going to proceed along different lines.

Before we begin — the inside diameter of the gas tube

Oh my, have some readers obsessed over this! They are busy redesigning the AJ the way it should have been, if only Umarex engineers were smart enough to have recognized it! I hear from AirForce all the time that they wish they were as clever as the people who redesign their airguns. But they know they aren’t, so they just let it ride.

The outside diameter of the gas tube measures 0.278-inches. The wall thickness of the tube measures 0.022-inches. That would make the inside diameter 0.234-inches. But when I measured the ID with my calibers I get readings between 0.135 and 0.155-inches. I know that my calipers are not the proper way to measure the ID of this tube, so I will hold up a 0.20/5mm pellet next to the tube and let you take a guess.

Air Javelin gas tube
That is a Sheridan .20 caliber pellet in the jaws of my Mitutoyo 8-inch dial caliper. The band at the base of the pellet measures exactly 0.2000-inches. The nose of the pellet that is next to the gas tube measures 0.1945-inches.

The test

I will shoot from a sandbag rest — the same as I did when I first shot the AJ at the SHOT Show. There I was 25 yards from the target. But Umarex had sighted the AJ in with a red dot sight and all I had to do that day was shoot it. Today I was on my own.


I started with the target bag 15 feet from the AJ. Yes I am using the back-up iron sights (BUIS), but since they detach from the AJ and I had to install them, I want to be certain of my shot! I taped a 10-meter pistol target to the center of the target bag to give me a more definite aiming point.

Air Javelin first shot
For the first shot I placed the target bag 15 feet from the AJ.

First shot

I have so many things to tell you about shot number one. First, the AJ is extremely easy to cock! Nobody will have a problem doing it. When the arrow is seated you cock the gun.

I was wearing my new hearing aids, so my description of the discharge sound will now be more precise.

The trigger is two stage with a looooooong first stage pull! The trigger then breaks heavily but cleanly.


I’m using the BUIS and you will remember that I told you that front fiberoptic is large. I decided to use a center-of-mass hold, which means holding the front orange dot in the center of the bull. That turned out to be a mistake, but I didn’t know it yet.

I will say this — the orange fiberoptic front sight gathers light extremely well. The thing glowed like it was battery-powered!


Load the arrow with the gun uncocked and on safe. It slides down the gas tube easily until it contacts the o-rings in the rear. Then it needs an extra push.

The arrow has two red “feathers” and one white one. On all bows the orientation of the odd-colored feather is important, but the manual makes no mention of it anywhere I can see. So I made it a point to load each arrow with the white feather pointing up.

Air Javelin loaded
The arrow is loaded.

Shot away!

The first shot went off with a loud report and a small cloud of CO2 gas. The arrow hit the target below the bull but in line with its center. Remember, I am holding the fiberoptic dot as close to the center of the bull as I can.

Air Javelin shot 1
The first shot hit the target about 3-inches below the aim point.

Move target to 11 meters

I moved the target bag out to what I thought was 10 meters. When I measured it from the tip of the arrow it was 11 meters. I adjusted the rear sight up and shot the second shot.

Air Javelin 11 meters
The target was moved out to 11 meters.

Shot two

Shot two hit the target about one inch below shot one and a little farther from the centerline of the bull. I had not known how much to adjust the rear sight up, so I didn’t go more than a full turn of the screw. I started hearing the clicks of the detent as I did this.

Air Javelin shot 2
Shot two hit below shot one and farther from the centerline of the bull.
It hit the back of the first shot, cocking it to the right.

Shot three from 10 meters

I adjusted the rear sight up a little and fired the next shot. It struck the target to the left of the first two. At 10 meters the fiberoptic front dot is almost as large as the bullseye.

Air Javelin shot 3
The third shot went to the left a bit. I’m still at 10 meters here, and the front dot is almost as large as the 2.5-inch black bullseye. I measured these three shots after withdrawing the arrows and the measure 1.617-inches apart, center-to-crenter.

Back up to 17 meters

I now moved back to 17 meters, which is almost as far as I can go in my little backyard. At 17 meters the front dot is larger than the bull! It is still smaller than the 8-inch kill zone of a whitetail deer, but I have lost a lot of precision with the target I’m using today.  That was what I meant at the beginning of this report when I said I probably picked the wrong sights for today’s test, but now I’m not so sure I did. Because of what I did buyers will have a good idea of how useful the BUIS are and can plan accordingly. I will guess that the BUIS will work to 25 yards on a deer. Beyond that a dot sight will be preferred, but in a hunting scenario you might want the dot for better visibility, anyway.

The first shot went “whump” — a decidedly different sound than the others had made. I could not see the arrow from where I sat so I walked up to the bag. The arrow was way low on the bag. That was why it sounded so different. Apparently the arrow dropped a by three inches when I moved back the 7 meters, so I had some more sight adjustments to make.

Air Javelin shot 4
From 17 meters with the same sight setting the arrow dropped another three inches.

Adjusted the rear sight one last time

I cranked the rear sight up as far as it would go and still allow me to hear the clicks. Let’s see.

Air Javelin sight up
The AJ rear sight is up pretty much as far as it should go.

Shots 5 and 6

The next two shots are from 17 meters with the rear sight cranked up pretty far. The first shot climbed on the target. 

Air Javelin shot 5
After the rear sight was adjusted up the next shot climbed back the three inches it has lost from the move.

Air Javelin shot 6
Shot 6 was higher and off to the left. I will tell you why in the report.

End of the test

At this point I realized that it was futile to continue. I had exceeded the fiberoptic sight’s range for accuracy. I was guessing where I was aiming and was off by several inches on every shot. I am almost certain that with a dot sight I can shoot near Robin Hood shots  (one arrow inside another) at this close distance, so it is pointless to continue.

Discharge sound

The AJ is loud. I call it a 4 on the Pyramyd Air sound scale. The sound does diminish as the gas bleeds down, but it still cracked on the 8th shot.

Shots 7 and 8

I went back outside when the sun was high in the sky and fired two more shots offhand from 20 meters. This time I was at the limit of my back yard, without shooting on an angle. Offhand I put two more shots into the target bag 1.5 inches apart and one inch below the aim point. This time there was no paper bullseye, so I aimed at the target bag itself, which was much easier. Perhaps we can stretch the range for the BUIS to 20 meters if you aren’t aiming at a small target. A grapefruit would be ideal!


I like the AJ a lot! It is just as much fun to shoot as I’m making it sound. And I think that once I get a red dot sight mounted we are going to see some real accuracy!

The first compound bow

by Tom Gaylord
Writing as B.B. Pelletier

Allen compound bow
This Allen bow is one of the first compound bows ever built.
Allen invented the compound system!

History of airguns

This report covers:

  • The first compound bow
  • A gift!
  • History
  • Description
  • Made for a southpaw!
  • Bow data
  • Tuning the bow?
  • Dimensions
  • Value
  • Summary

I was looking for something completely different  for today’s report. I was temporarily bored with my list of airguns to cover and I didn’t feel like another rant, so today I am reporting on something that is in the shooting sports, but a long way from airguns — the world’s first compound bow.


About two months ago, and just before my town locked down for the Covid-19 pandemic, I was in my favorite pawn shop, looking to see what new/old things might have come in. Naturally I searched the whole store, as I always do. There are things on my watch list, like a long-bladed plain-head screwdriver with a wide tip, that I’m always searching for. I didn’t see anything interesting until the very end, when I spotted a strange and simple-looking compound bow standing in the corner by the gun rack. It looked homemade so I asked to see it. I wasn’t interested it it beyond seeing how it had been made. It looked for all the world like something that had been built from plans published in Popular Mechanics.

The first compound bow

As I was looking it over, Esther, the store owner who knows my eclectic tastes from my years of patronage, came over and told me it was the first compound bow. Well, it certainly looked like it! She told me it had been in her store for many years with absolutely zero interest, and I could see why. This wasn’t a bow anyone would ever shoot. And how many collectors of compound bows are there? About as many as there are collectors of 4-track tapes — yes, there is such a thing. Look it up! I did, and to my surprise I discovered there are even collectors of them! Okay — bad comparison.

But this bow is a different story. Most people buy bows to shoot. Looking at this one, I think that would be a very bad idea!

A gift!

As she was talking to me Esther surprised me by giving it to me. She said she wanted it out of her store and I could take it. Well, I had no idea of how much a thing like this is worth, and I certainly did not want it for myself, but I figured I could give it to an archer, so I accepted.


I came home and looked it up on the internet. It was marked as an Allen Patent, so I started (and ended) there. Sure enough, Holless Wilbur Allen (1908-1979) was the inventor of the compound bow! He developed his idea in the 1960s with the thought of making bow hunting easier. He sawed off the ends or a recurve bow and added pulleys to each end. His idea was to use a block-and tackle design to reduce the effort of holding the bow at full draw and also increase the speed of the arrow. He experimented with several designs and on June 23, 1966 he applied for a patent. The U.S patent 3,486,495 was granted in December, 1969.

Allen patent
The patent drawing resembles the first bow very closely.

At first he approached several archery manufacturers to build his bow for him, but with no takers he started making them himself. He referred to his patented idea as an Archery Bow with Draw Force Multiplying Attachments — and began production in 1967. He said of it, “All I was trying to develop was a bow that would get an arrow to a 10- to 25-yard target — a deer — before the target could move.”

The technical editor of Archery World magazine (now Bowhunting World), Tom Jennings, reviewed the Allen bow in the May 1967 issue and said things like, “reduction in peak draw weight”, “more stable than recurves” and “the first really new concept to come into bow design in a thousand years.”  He became the first to license the design rights from Allen who also licensed his design to four other companies, of which Browning Archery was probably the most successful.

The first compound bow was not readily accepted by the archery community. Given the size, weight and most of all the complexity, that isn’t surprising. But Tom Jennings, who was also a bowmaker, stepped in and in 1974 released his Model T that revolutionized the infant compound bow.  Until Jennings Model T, compound bows were clumsy and complex.

While other companies were still using four and six wheels for their bows, Jennings Model T used only two. It was lighter, and easier to tune. Sales went from sluggish to brisk. By 1977 Archery Digest listed more than 100 models of compound bows and they had taken over the archery world.

Allen died from injuries sustained in a car accident in 1979. But he might have had had a succession plan set up because a company called Allen Archery still makes bows today.


This first Allen bow is clunky compared to later designs. I’m not talking about the compound bows being made today — just those that were made soon after Allen started licensing his and the Jennings Model T came out.

The first Allen bow has six pulleys in the system That’s right — six! Two are at the end of each limb and the third is inside a guard on each end of the handle.

Allen pulleys
Two pulleys are at either end of the bow limbs. As you can see from the clasp at the bottom left, most of the bow is strung with stranded steel cable. The bowstring is just a short section in the middle, at the back of all the cables.

Allen pulley
The third pulley on each side is attached to the bow’s handle.

At some point, Allen called his bow the Original. That is on a sticker on the bow I have.

Allen Original
My bow is an Allen Original. The black bar on front of the handle is for some accessory — probably a sight? And the arrow rest is on the left side of the bow.

Made for a southpaw!

Of all things, the bow I was given is made for a left-handed shooter. I didn’t figure that out. Reader Jeff Cloud who goes by the handle Cloud9 spotted it. It’s almost ambidextrous, which might have been intentional, but it does feel better when held by the right hand and the arrow is drawn with the left.

Bow data

Like all the bows I have seen, the data for the bow is written right on it. In this case it is inscribed with a vibrating pen on one of the black steel flanges that hold the limb to the handle and also anchor the single pulley.

Allen data
The bow data was put on with a vibrating pencil. The model is 7306-10. The draw weight seems to be 50-60 pounds. The draw length is 29 inches and the L at the end of the serial number would seem to indicate a left-hand model. I can guess that the serial number indicates this bow was the 304th made in December of 1975.

Tuning the bow?

This is a subject I know nothing about, but I do see what look like stringed instrument tuning mechanisms that attach to the lone pulley on either side of the handle. A cursory examination indicates they move the axel of the pulley, which may change the mechanical advantage.

Allen tuner
The lone pulley on either end of the handle has what looks to me like a stringed instrument tuner. It seems to move the center of the pulley axel.

Allen tuner detail
This is what’s written on each “tuner.” I hope someone recognizes what this is.


This bow weighs 4 lbs. 4 oz, which seems light enough to me. It has an overall length of 50 inches, and of course the draw weignt has already been given.


At some point in its run the 7306-10 model was called the Black Hunter. My bow has no such markings, but they may have been in the catalog and not on the bow, itself.

Expired listings on Ebay show asking prices for the standard model of $175-$195 without any bids. One that is active is up to $81 with 6 bids right now. There are several Buy it Now listings that sold for less than $150. So the value of these bows is not high. I guess that’s because they cannot be used anymore.


I think it’s interesting how the first compound bow is so relatively recent — or at least that’s how it seems to me. And also how quickly the archery community accepted the compound, once it was refined into a convenient form. The compound dominates center stage in the world of longbows today.

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.


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.


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.


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!


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.