Precharged pneumatics, regulators and power adjusters: Part 2
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Mac’s gun
- Difference between the Talon and Talon SS
- Long barrel
- Air flow is the key
- The Condor
- The Freimarked rifle
- NRA airgun range
- For RidgeRunner
It seems like you readers are hot for more information on tuning valves and adjusting power on precharged pneumatics (PCP). Very well. In response to something RidgeRunner said yesterday, I will do Part 2 of this report today.
It began many years ago with my friend, Earl MacDonald — Mac. He was of the opinion, shared by many airgunners, that a high-velocity .177 caliber pellet will be most accurate at long range because it will drop less over distance. So, he wanted the mostest-fastest .177 ever made. He talked to AirForce, where I worked at the time, and convinced them to let me build him a super-fast .177 Talon from blemished parts. In those days production was smaller than today and we didn’t have as many blemished parts around. Still I managed to find the parts I needed to assemble the gun.
Difference between the Talon and Talon SS
Many airgunners say “Talon” when they are referring to the TalonSS. They are two different air rifles. The Talon has an 18-inch barrel and no sound suppression. The TalonSS that is suppressed has a 12-inch barrel that is tucked inside the frame of the gun — in something airgunners call a shroud today. AirForce pioneered this design in 2001, when they brought the Talon SS to market, and they have been refining it ever since. They were not the first company to offer a shrouded barrel on a PCP though. That honor falls to Davis Schwesinger of the now-defunct Air Rifle Specialists, who added his own shroud to the Career 707s he sold. AirForce Airguns was the first manufacturer to design a shroud into an air rifle on purpose.
Mac had a 25-inch Weihrauch .177 barrel that was made for an AirForce rifle that he bought from the company, Mac I, so that became part of the rifle. I took a valve that was built for power by decreasing the return spring rate by a couple pounds so the valve would open easier. I also raised the height of the top hat considerably higher so the valve stroke would be longer — meaning the valve would stay open longer. Use it on a TalonSS with a standard 12-inch barrel and all you would get was a louder rifle with no appreciable velocity increase. But put it on a rifle with a super long barrel and you got what Mac was after — a Talon that would shoot H&N Baracudas supersonic. I believe that is the rifle that RidgeRunner now has, because he reports Baracudas going supersonic. A Talon with a standard 18-inch Lothar Walther barrel and a standard valve would be shooting the same pellet in the low 900s with the power adjuster set all the way up.
Air flow is the key
RidgeRunner was right when he said air flow is the key to velocity. However, it has to be coupled with a barrel that’s long enough to benefit from it or all you do is waste air and make noise.
In 2004, when AirForce brought out the Condor, the world received its first supersonic .22 pellet rifle. I mean one that was purposely designed that way — not one that somebody goofed up with hairspray or oil down the transfer port. The Condor valve has a huge air passage compared to the standard AirForce valve. I was as amazed as the rest of the airgun world when I saw the performance, which I did firsthand. AirForce was so concerned that the rifles lived up to their advertising that we chronographed the first 100 and recorded their velocity by serial number — just so we had the proof. That was where my story from Mr. Condor that I mentioned last week came from. When he brought us his bag of parts we knew exactly when it had been sold and to whom. And also how fast it shot when it left the fsctory. And when I say “we” tested every one of them, I mean me. I shot each one of them through the chronograph while the numbers were recorded.
The Condor was a big lesson to me, but it turned into an even bigger lesson when we wanted to send our rifles to the NRA for inclusion on their indoor range at the NRA Annual Meetings and Exhibits. Before I tell you this tale, though, you need to know another behind-the-scenes story.
The Freimarked rifle
Germany has a law that an airgun cannot exceed 7.5 joules (5.5317 foot-pounds) of energy at the muzzle and still be considered an airgun. In Germany, airguns have traditionally been used for target shooting and this power limit is plenty of energy for that. If the gun develops more than 7.5 joules, it must be registered as a firearm, and other laws, like who is legally allowed to shoot it without supervision, come into play. Airguns that meet this requirement are stamped with the letter F inside a pentagram and are considered free (frei — hence Freimark) from legislation. There are rules that govern the use, possession, transportation of airguns, as well, but they are considered free from the more restrictive firearms legislation.
However, there is no way that a conventional AirForce rifle can meet that low power requirement. Most of them cannot even be dialed down to that low level of power, but even if they could, the fact that they have adjustable power that exceeds 7.5 joules makes them non-compliant. We wanted to sell airguns in Germany, so a special valve was designed to restrict air flow. I won’t tell you how we did it, but once it was done the rifle used only the air that was inside the valve body at the time of firing. It worked well.
NRA airgun range
Then came the opportunity to be on the NRA indoor airgun range at the annual meetings and exhibits. This is a show that’s open to the public, and in recent years over 60,000 people have visited it. But we could not be on the range with our guns because the NRA uses pellet traps that were given to them by Daisy, and AirForce rifles can shoot right through them!
So I took the valve that was developed for Germany and found a second way to restrict the airflow — making a double-restricted valve. Once it was installed on a Talon SS there was no way that rifle could be adjusted to get much over 5 foot pounds. I showed it to John McCaslin, the owner of AirForce, and he tweaked it further, then built several rifles for the NRA. As far as I know, they are still being used on the airgun range.
But that’s not the end of the story. After seeing what could be done, I lobbied long and hard to make and sell this setup to the general public. With a tank containing such a valve, a shooter could take his 30+ foot-pound Talon SS and turn it into a quiet, safe indoor target rifle his whole family could enjoy. Not only was it safer and quieter — it also gave over a hundred shots per fill. We knew that from our experiences on the NRA range. The MicroMeter tank was born! I never envisioned it but owners of the more powerful Condor are also buying the MM tank. Sometimes less is more!
In this report I have talked about airflow. But I left out something that most of you haven’t considered. Increasing or restricting the air flow is an important part of the power control equation, but there is more to it. When it comes to restricting air flow it’s not just how much you restrict the flow but also WHERE you restrict it. Restrict it in some places and the power will drop but the gun will still respond to power adjustments. Restrict it in other places and the power will drop without the possibility of ever increasing again.
I cannot tell you more than that or I give away design secrets, but let me give you an analogy. Let’s say that the city of Los Angeles needs a lot of water. And let’s say one place they get it is from the Colorado River that flows through the Grand Canyon. Let’s say this water ends up in a large man-made lake called Lake Meade that’s contained by a big dam — we’ll call it Hoover Dam.
Hover Dam can control the amount of water that’s sent to Los Angeles by controlling the output of water that gets past the dam. However, if the water level in Lake Meade falls too low, it won’t be Hoover Dam controlling the output of water. There won’t be any water at the dam because the level is too low. In that instance you can open all the dam’s floodgates and it won’t make any difference. That’s as much as I can tell you about how to control airflow.
I don’t know if you picked up on it, Michael, but I talked about power adjustment in both Part 1 and again today. But that wasn’t all I wanted to say. It was your questions about power adjustment that started this report and with power adjustment I will finish it in the next part.