Normally you connect your fill adaptor to the airgun. Then slowly open the tank valve to pressurize the gun to your desired fill level. When you finish this process, you close the tank valve, bleed off the remaining air in the lines, then finish by disconnecting the air hose. This is standard PCP filling and that is all most people do. That is why most of the inexpensive fill adaptors have short hoses.
When you leave the hose from your fill adaptor connected to your air gun (without bleeding the air) we call this tethering. The two biggest advantages to tethering are first you save air, because you are not bleeding it off between fills. The second advantage is convenience. If you are doing a lot of shooting from a bench or fixed position it is great to be able to just reach over from time to time and crack the valve to refill your gun. With a long hose you can easily do this without getting up. Gene and I love to shoot our guns tethered, that is why we designed our STIKMAN PCP fill adaptor with such a long microbore hose. Gene usually has his SCBA bottle with STIKMAN attached sitting in a 5 gallon plastic bucket next to his shooting bench, look for another blog post on the 5 gallon bucket. I like to have my 44CF or smaller bottle resting on the bench under my bipod. With the long hose on the STICKMAN you have the flexibility to put it anywhere you want.
The only downside to tethering is that you have to have one fill adaptor dedicated to each gun. If you and a buddy have to share a single HPA tank and fill adaptor, this will not work for you. If you are in this position, you will need to pick up a 2nd. tank and fill adaptor so you can each tether your airguns. When you purchase the 2nd. fill adaptor make sure it is a STIKMAN so you will have the long hose and the ability to cascade fill as well.
There are 3 different ways to tether your PCP airgun.
The first is to just leave the fill adaptor tethered to the gun to save air, and convenience as stated above. another advantage to leaving the gun tethered
The second way is what I call the self regulating tether.
Sooner or later after filling your PCP airgun enough times the air remaining in the tank will reach a point that it is at or below your guns desired fill pressure. For some people this means that they will continue using the bottle to fill the airgun to as high as possible. Then they will bleed the air, remove the hose. Once this happens you will never get the normal number of shots you usually get on a fill because you are unable to fill the air gun up to the desired level. At this point withe each fill cycle you get fewer and fewer shots. You also spend more time filling and less time shooting. Here is where the self regulating tether comes in.
Once the pressure remaining in the air tank equalizes with the reservoir in the airgun, simply leave the fill whip connected and the valve slightly cracked. Magically each time you fire the gun, the pressure in the tank will once again equalize with air in your airgun reservoir. This does a few things.
First it in theory turns the normally small air tank on your rifle into a massive air reservoir. Because you are combining the volume of both the tank and the reservoir. This allows you to continue to shoot for a long time. You can continue to shoot the now large air reservoir of air all the way down to the point you normally stop to refill your airgun. When you do this you are going to get a ton of shots and more useable air out of your air tank before refilling it.
The next benefit is that now having a very large reservoir to draw air from you really flatten and lengthen the bell curve of the shot string. This keeps your shot-to-shot pellet velocity (expressed in feet per second – FPS) very constant. Now on longer percussion shots need to think about where you are in the bell curve of the shot string.
Third way is the regulated tether…
This is where you connect a external regulator like our REGMAN, or a small regulated paintball tank in line with the fill adaptor. Usually you set the regulators out put pressure to where your airgun is the most accurate, or with a paintball reg you set it to the max fill for your gun if you want. When connected through the regulator you can leave the valve cracked on the tank and the regulator will keep the pressure entering your airgun at a set level. Now along with the benefits mentioned above you also get the benefits of having a regulated airgun and no bell curve. You get to enjoy this until the pressure in the tank drops below the regulated set point. After that it turns into a self regulated tank as mentioned above.
We hope you found this to be informative and helpful.