Beeman R9 with Vortek center-latching air piston: Part 1
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- The Vortek unit
- Filling the unit
- How it works
- Spring guide
- Barrel goes back
- End cap in
- How long and how difficult?
I try to stay away from products that are not available, but today I’m starting a look at a new gas piston unit for the Beeman R9/Weihrauch HW95 breakbarrel rifle. This report will be unique in several ways. First, it is the first look at a new Vortek gas spring unit that may either be available from Pyramyd Air or from Vortek directly. Second — the R9 I’m using for this test is in .20 caliber. I know there are many shooters who favor .20 caliber, but many more who don’t. I will address that as the report unfolds, but let me state for the record that, except for testing a Sheridan Blue Streak or Supergrade, I haven’t tested another .20 caliber air rifle in many years!
The Vortek unit
This new gas piston is so new it doesn’t even have a name as I’m writing this. I will call it the center-latching unit, or CLU for short. It came to me as a kit that included the unit, a piston seal, a white spring guide and an adaptor. But, an adaptor for what?
The CLU kit came with the unit, piston seal, spring guide and fill adaptor.
The adaptor is one of the things that makes the CLU special. It’s a fill adaptor that has a male Foster filling to attach to a source of high pressure air — preferably a hand pump. You see, this unit is filled by the owner!
Theoben used to allow users to pressurize their gas springs many years ago. I’ve owned several Theoben rifles with this feature. The problem was, too many owners were over-pressurizing their gas springs in attempts to get the last f.p.s. of velocity, and they were ruining their airguns. Ben Taylor — the Ben of Theoben — once told me that owners would pressurize their gas spring too high, turning them into slide hammers that beat their rifles apart. Davis Schwesinger told me the same thing, and I have shown you the results of such abuse.
This piston seal was taken from a Theoben rifle that had been shot while over-pressurized. The rifle was losing power as the piston seal vaporized.
The Vortek unit doesn’t fix stupid. You still have to use sense when you manage your own gas piston pressure, and this report will look at how that’s done. And, if you are going to tune the unit, you have to have a chronograph. Sorry, guys, but the “back door to the hickory tree” chronograph won’t work for this. You can still fill the unit with a hand pump and it will work, but a chronograph is needed to refine it. I will tell you the pressure I filled to in a moment.
Filling the unit
Vortek sent me the unit with a low pressure inside to keep the inlet valve closed. I was to pressurize it myself. I was told it would take just 8 ot 9 pump strokes, but that will only work if I have the exact hand pump they use. Not just the same model — the same pump. Because things like the length of the fill hose will play into this. And it did. They have a 6-inch microbore hose. Mine is 24 inches liong. The hose is going to take more air to fill.
So, fill the unit until it has at least 45 bar of air pressure inside. That’s 653 psi. But you can go up to 700 psi and still be okay. I filled the test unit to 675 psi for the first test. The muzzle velocity will tell me what to do after that.
The fill adaptor on the right is screwed into the top pf the piston, left. The ridge in the center of the flats of the piston are where the cocking shoe rides.
How it works
When I first examined the unit I found it impossible to compress the rear latch of the piston. It didn’t move! Vortek had told me there was just a maintenance charge of air in the unit, and I thought I should be able to compress it easily. So I called Vortek.
Tom Gore told me I could put all my weight on the latch — it still wouldn’t move. Because it never moves. He had me put the white plastic spring guide on the tail of the piston and then press down. That worked! Okay, this unit works differently that any one I’ve ever seen.
Here we see the end of the piston that engages the end of the white plastic spring guide. The hollow end of the guide fits into that groove on the back of the piston and shoves it forward. This is an entirely new way for a gas piston to work, and it is patented.
The ridge in the center of the flats of the piston is where the cocking shoe rides.
Pyramyd Air sent me the R9 rifle they display at trade shows. It had no mainspring, because no gun inside those shows can be operational. So, disassembly should be pretty easy. But I haven’t taken an R9 apart in a long time, so let’s see how it goes.
First the rifle comes out of the stock. The rest of the installation is done on the barreled action. Now remove the Rekord trigger.
The mainspring is out of this gun, but if it was in the gun a compressor would have to be on the end cap before the next step.
The R9 doesn’t have a threaded end cap like the Beeman R1 and other Weihrauch airguns. Instead, the end cap is held in by one locking flange and four tabs. A new R9 can be somewhat tedious to take apart because those tabs that have to come out first are very tight in their holes.
If there was a mainspring in the gun the end cap would be under tension at this point and a mainspring compressor would have to be used. This one had no spring, so the cap slid out easily.
Because there was no mainspring in the gun, things have been easy to this point. But there is still a piston inside, and it needs to come out for the CLU to be installed. To get it out, the barrel has to be removed. That’s because the cocking linkage cannot be disengaged from the piston with the barrel installed. The link is too long and won’t allow us to move the cocking shoe to the enlarged slot in the spring tube for removal.
Taking off the barrel is not hard. The pivot bolt nut comes off and the pivot bolt can be unscrewed from the spring tube forks. Once the bolt is out that barrel separates from the spring tube. Now the cocking shoe can be removed from the spring tube, and that frees the piston to be removed.
Now the gun is ready for the Vortek center-locking air piston. It’s as long as the Weihrauch piston we just removed, plus there is the white plastic spring guide in the rear.
I haven’t said anything about the Vortek piston seal yet. It’s impregnated with moly, so no lubrication is required. It covers the fill port where the air is pumped in, and it just snaps in place.
Now I slid the Vortek CLU and spring guide all the way into the spring tube. Once the ridge in the center of the flats on the CLU is aligned with the center of the cocking slot, the cocking shoe and cocking link can be installed in the spring tube, where it engages the Vortek CLU.
Barrel goes back
Now the cocking shoe is inserted in the spring tube to connect with the CLU. I greased the bottom of the shoe with moly paste before installation. Once it’s in, the barrel is reconnected with the spring tube and the pivot bolt and nut are tightened.
End cap in
At this point, the end cap goes back in the spring tube. It slide in almost all the way, and stops when it contacts the end of the spring tube.
As you can see, the end cap goes back in the spring tube almost all the way. A mainspring compressor is needed to push it all the way in. I used the Air Venturi Rail Lock compressor.
Once the end cap was in I rotated it so the locking flange aligned with its slot, then I tapped in all 4 tabs. The compressor was removed and the safety and trigger went back in. Remember to cock the trigger before installing it, to make it easier to align the pin holes.
The barreled action then went back into the stock and all bolts were tightened. Time to test. The rifle cocked and fired the first time, so everything works as advertised. I’ll give you a detailed performance report next time.
How long and how difficult?
This job took me one hour, start to finish. The hardest part was getting the R9 apart. Those pesky tabs were new and resisted removal for about 25 minutes. Other than that, this was no more difficult than replacing batteries in a flashlight. More things to do, certainly, but no more difficult. I’ve done this sort of thing many times, though, and I have the right tools, which include a pin punch set, a plastic hammer, a mainspring compressor and a small Allen wrench.
Remember I also had to compress the CLU, which took a hand pump. The adaptor came with the unit, but a high-pressure hand pump was required.
The beauty of this unit is if I don’t like how it shoots, I can disassemble it and change the pressure in the unit. I will show that in a future report.
Next I will test the velocity as it stands right now. Pyramyd Air sent me samples of every .20 caliber pellet they sell, so we have the whole field to test.
I will also be testing accuracy down the road, although that isn’t the focus of this report. But, as long as I have the R9, why not?