This report covers:

  • How do you know?
  • I called AirForce
  • It’s funny
  • Not foolproof
  • BB makes mistakes, too
  • What about other powerplants?
  • Summary

Today will be a strange report. I received this question/comment to an older report:

“Hi. I wonder if you can help-I have an original Gunpower Stealth from the initial 250 batch and the bottle leaks slowly from the centre of the top hat. I put 100 bar in and put it in a glass of water and saw the bubbles. It is the early valve as you have pictured here. Do you know how to disassemble so I can inspect the valve-with help from a friend? We got the valve out of the bottle — after 23 years of being undisturbed! There is the white nylon Allen hex bolt which, once unscrewed, allows the spring to come out and then the internal white nylon portion has the top hat stem coming through. I presume into it and it does not unscrew so how do I get them apart? Is it simply pull apart-fearing damaging the internal portion! If I cannot disassemble, can I safely use silicone spray to lubricate as I am only hand pumping?


If I need to replace the valve there are Condor Talon valves for sale on ebay from China and all appears to be the correct size but the aperture at the centre of the top hat is 5.5mm or larger whereas mine is just under 2mm what will this mean-will I turn my legal under 12ft lb into a firearm with the larger aperture? Appreciate any advice, many thanks Peter

Peter — there is a lot wrong with your question. I’m not blaming you, but you have gotten ahold of some VERY BAD information.

First — you don’t disassemble a GunPower Stealth or AirForce valve when it leaks slowly. You pressurize the tank and then hit the top hat with a rubber mallet. The force of the rapidly exhausting air will blow out any dirt that may have gotten on the soft surfaces of the valve. I have built thousands of these valves for AirForce and that was how I both tested them and set the valve to seal. I also repaired the leaking guns that were returned and my method fixed about half of them.

But take one apart and you are in trouble. What is the torque spec for a GunPower Stealth valve return spring? You don’t know? Neither do I anymore. But get it wrong by an inch-pound and you will never get the rifle to shoot correctly. That’s when guys start boring out the valve orifices, because they over-torqued the return spring to 23 inch-pounds when it should be 17.5 inch-pounds. Do you even own a torque wrench that’s calibrated in inch-pounds? And you can forget the 17.5 inch-pounds for the GunPower Stealth valve return spring. I made that up. I don’t remember what it really was.

Okay, now what about those Condor Talon valves for sale on eBay from China? Well, the Condor and the Talon are completely different air rifles that have completely different valves. So, if somebody is selling a Condor Talon valve it’s like a Mercedes Ford engine. They aren’t the same and no amount of broken English is going to make it so.

And that white nylon portion at the opposite end of the Top Hat stem (the valve stem) is the actual valve. It is pressed on and that end of the stem is splined, if I remember correctly.

How do you know?

Where is Peter supposed to find this information? It’s really not out there. Don’t go on forums and ask or you’ll get answers from couch commandoes who have never owned one of these rifles but have read many conversations between those who did. They didn’t understand them and they are only too willing to pass along what they don’t know.

If you don’t know, go to the source. Call or email AirForce Airguns and ask what can be done. Now, I doubt they will tell you to tap the top hat with a rubber mallet like I did, though when I worked there and took the service calls, that’s exactly what I did. That stopped many airguns from being shipped to us needlessly.

I called AirForce

Peter, though you didn’t say so I got the impression that you are living in the United Kingdom (your spelling of centre). I live in the same US town that AirForce is in, and I used to work there. So I called them for you.

They told me that if you are in the UK they would refer you to Elite Optical for service issues. Elite would possibly sell you a valve. But here is the deal. The GunPower Stealth has been upgraded over the years along with the Talon and TalonSS. So you might need an entire new valve, because the old internal valve parts are no longer being made. But the new valve would have to be a 12 foot-pound valve like the one in your rifle to be legal in the UK without a Firearm Certificate. So, after installing it in the tank you probably wouldn’t notice any difference.

Peter, a better thing to have done would have been to post your problem on the blog and let BB tell you about his fix. But don’t fret; BB sometimes does the same thing. He understands!

It’s funny

You know, it’s funny, but you tell somebody how to do something and when it works they thank you and you never hear from them again. That person now knows “the secret.” But until you have the same experience, you don’t know it. Learning things like this is a personal thing — unless you read this blog. Then you can learn by reading what others have done.

The last thing you ever want to do is disassemble a pneumatic valve before doing this tapping/mallet test. With the AirForce/GunPower airguns this test is easy to do because the end of the valve is exposed at the end of the removable tank (it’s the top hat), but what about a gun whose reservoir is internal? How do you do this with a Benjamin Marauder? Well, you dry-fire the rifle and let the internal hammer do the work. It isn’t quite the same because with the rubber mallet you can regulate your blows better than you can when you rely on an internal hammer, but the idea is the same. You are trying to blow dirt off the soft parts of the valve, which the rapid exhaust of air does — sometimes.

Not foolproof

This technique doesn’t always work. If the synthetic valve face is cracked or if it has a nick in an edge that should seal you can do all you want and this won’t fix the problem. And sometimes it isn’t the valve itself, but a seal around it. Peter, you did what we all have done. Lacking information you tackled the job yourself.

Build a Custom Airgun

BB makes mistakes, too

I have a metal detector that’s about 20+ years old. I wanted to use it for a backup machine in case my new Minelab detector ever goes on the fritz. So I put fresh batteries in and I turned it on. Nothing. I tried all the knobs and still nothing. I removed the battery pack and switched the polarity in case I had gotten it wrong and still nothing. So yesterday I put the batteries in the correct way again and then packed the detector in a box and prepared to ship it to a repair station today. 

I was awakened at 3 a.m. this morning by the shipping box humming. I had left the detector turned on with the batteries installed and overnight it had healed. I shouldn’t have done that, but wow! I checked the functions and they all seem to work well. What a blessing! Instead of being out a $100 minimum service charge with return shipping, I lost $4.50 for a shipping box and some bubble wrap. Stuff like that doesn’t happen often enough, but when it does I take notice.

What I’m saying is slow down if you can. Don’t jump into a project right away just because something isn’t working. First find out if what is happening is a common problem and perhaps you will find a common solution at the same time.

What about other powerplants?

What I have just written for Peter applies to a PCP, and is really oriented toward an AirForce/GunPower PCP more than others. This technique does work on CO2 guns sometimes, but they don’t usually have this problem. If they have slow leaks they are usually caused by a broken or punctured o-ring or a ripped face seal (the seal that a 12-gram or 88-90-gram CO2 cartridge seals against when pierced.

I would love to turn this into a series, but I don’t see how it applies to spring-piston guns. Can anyone offer me some help in that regard? I can see expanding to single-stroke pneumatics and multi-pump pneumatics if there is enough interest among you readers. Here is what I’m talking about. When your airgun starts developing problems, what are the common reasons and are there some simple fixes you should try?

Summary

You know, for every well-thought-out comment like Peter made yesterday I get a dozen from recliner rangers who want to chop off 6 inches of barrel on a springer because they hear the longer barrel slows the pellet down. Then they crown what’s left with a brass button screw and hate it because it’s now so hard to cock. Peter has just lost his best shooting buddy and wants to get him back on the road as soon as possible. That’s what I want, too.