AirForce Edge 10-meter target rifle: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

AirForce Edge.

Part 1
Part 2
Part 3
Part 4
Part 5
AirForce Edge 10-meter target rifle: Part 1
AirForce Edge 10-meter target rifle: Part 2

A history of airguns

This report covers:

  • Accuracy day
  • Dropped a shot
  • What was happening?
  • The problem
  • Went to AirForce
  • Adjusting an Edge top hat
  • Purpose of the o-rings
  • Adjusted the top hat
  • RWS Basic
  • H&N Finale Match Light
  • RWS R10 Match Pistol
  • Sig Match Ballistic Alloy
  • Shot count
  • Off the regulator
  • One last thing
  • Summary

Oh, boy! Every once in awhile something big happens with this blog, and today is a report on such a time. This is about the AirForce Edge.

To tell the complete story I first have to tell you some bad news. I want you to read it without getting angry, because if it hadn’t happened as it did I would not be able to tell you the extraordinary news I’m about to tell you.

Accuracy day

This report was supposed to be the first test for accuracy. I knew there were going to be several accuracy tests, but this would be the first one. Except the rifle didn’t cooperate.

I spent a hour sighting in and then shooting the first three groups. I have a lot to tell you about adjusting the rear sight, but that will wait until another time, because what I have for you today is much more important.

Dropped a shot

I was shooting RWS R10 Match Pistol pellets that showed every possibility of grouping extremely well — UNTIL! Until I heard a shot go out that was audibly much slower than the rest. When I looked through the spotting scope I saw that pellet had dropped about a half-inch. A half-inch for a 10-meter target rifle shooting at 10 meters is like trying to fly to Buffalo and landing in Cleveland, instead! I was shocked!

I thought the only thing to do was shoot another group and see what happened. The first two shots went through the same hole, then shot three landed a half-inch below them and shot four was another half-inch below that. Test over!

What was happening?

I took the rifle back to my office and examined it, and the o-rings that both Chris USA and GunFun1 commented on in Part 2 were even more off-center than before. Okay — BB was wrong when he told Chris USA there was no problem with those rings. Apparently there was a problem. But it wasn’t with the rings themselves. Wait for it.

Edge top hat
This is the photo that several readers didn’t like. They felt that the o-rings sitting askew like this was messing with the rifle’s output. There was a problem, but this wasn’t exactly it. Still, these o-rings don’t have to look like this.

The problem

We haven’t gotten to the problem yet! But I thought I would remove those two o-rings and replace them with something that fits the valve stem better, and do you know what I discovered? The two Allen screws that anchor the top hat to the valve stem were not tight! Every time I closed the bolt, it rotated the top hat by a small amount — or at least it had the potential to! That was the problem!

Once the top hat was off the valve stem, I removed the two o-rings AirForce had installed and replaced them with two metric 007 Buna o-rings. But you need to understand that those o-rings have very little to do with the velocity of the airgun! The distance that the top hat travels has a lot to do with it! And there is more. I have more to tell you about what the o-rings do in a little bit, but right now let’s move on.

Went to AirForce

I took the AirForce o-rings and one of my 007 o-rings to AirForce to speak with Ton Jones who had personally set this rifle up for me. I told him the Allen screws that lock the top hat in place had not been tightened and he was surprised — at first. Then he remembered that he had set up this valve and reservoir for me and gave it directly to me, instead of sending it on to the next AirForce station. Ton had snugged both screws down but not tightened them. At the next station another worker unscrews each Allen screw one at a time and dips it into blue Locktite! Then the worker tightens the locking screws tight so the top hat remains were it was adjusted by either Ton or one other person who adjusts each Edge over a chronograph. 

I showed Ton the Part 2 photo of the top hat with the wonky o-rings (shown above) that you readers took exception to. He said yes, the rings askew like that is a problem, but not a big one because the top hat isn’t supposed to even touch the top o-ring when it is set correctly.  HUH?

Adjusting an Edge top hat

What I am about to tell you has only come to light in the past month. Until right now AirForce had a different procedure and specification for adjusting the Edge top hat. But Ton Jones took an Edge to his wife’s parents’ home in Slovakia on vacation last year and he got it working very well. When he told the owner of AirForce about his experience he was asked to determine exactly what he had done and write it all down for a new specification. That work took him many weeks, intermingled with his other duties, but he has now codified the top hat adjustment procedure for everyone.

To adjust the Edge top hat, first make sure both of the locking screws on its periphery are loose and the top hat turns freely on the valve stem. Then cock the rifle and watch the top hat as the bolt comes back to its rearward position. When the top hat just turns just a little as the bolt is closed, it is adjusted correctly. With the o-rings AirForce was putting on the valve stem there will be a clearance of about one o-ring’s width above the top o-ring and the bottom of the top hat when it is set properly. With the fatter o-rings (the metric 007 rings) that I am using, there is only a thin sliver of clearance between the top of the o-rings and the bottom of the top hat. Each rifle is different though and must be adjusted by hand this way.

Purpose of the o-rings

The o-rings are there to control the amount of distance the valve opens — BUT by the time the top hat starts to compress them, the pellet is almost out of the barrel. They don’t really control the velocity of the pellet; they control the amount of air that’s wasted after the pellet leaves the barrel. The valve return spring tension, the length of the valve stem travel (controlled by the top hat) and the regulator pressure setting control the pellet’s velocity. And each airgun is different.

I have prepared a short video to show you how the top hat is adjusted.

Adjusted the top hat

After I filmed that video I adjusted the top hat as shown and locked down the two locking screws. I am now ready to test the Edge velocity again — this time knowing the top hat will not move.

As I shoot I’m not allowing any particular amount of time between shots. I watched the clock and it seemed as though it took me 20 seconds to do everything between each shot. So that is the interval for the shots that follow.

RWS Basic

Once again I used the RWS Basic pellet as my principal test pellet. In the first string after filling the rifle to 3.000 psi Basics averaged 534 f.p.s. How interesting that number is so close to what they did the last time. This time all pellets were seated thumb deep. The low was 518 and the high was 545 f.p.s., so the spread was 27 f.p.s.

H&N Finale Match Light

Next to be tested were H&N Finale Match Light pellets. They averaged 523 f.p.s. with a low of 510 and a high of 540 f.p.s. The spread was 30 f.p.s.

RWS R10 Match Pistol

The third pellet I tested was the RWS R10 Match Pistol pellet. Ten of them averaged 554 f.p.s. The low was 539 and the high was 567 f.p.s. So the spread was 28 f.p.s.

While shooting this string I got curious if a longer wait between shots would tighten the velocity spread. So for the first 5 shots in the next string of the same R10 Match Pistol pellets I waited 60 seconds between each shot, and for the last 5 shots I waited my normal interval, which is about 20 seconds.


Then I waited the normal interval between shots, which is about 20 seconds.


I seems like shooting at the normal interval of about 20 seconds is more consistent than waiting a minute between shots

Sig Match Ballistic Alloy

The last pellet I tested was the Sig Match Ballistic Alloy wadcutter. They averaged 634 f.p.s. with a low of 621 and a high of 642 f.p.s. That’s a difference of 21 f.p.s.

Shot count

Now the real test begins. I will shoot RWS Basics for the remainder of this test. How many shots will Ton Jones’ method of adjusting the top hat produce? I shot the rifle up to 169 times, which is too many to show to you here. So I will encapsulate.

Shot 51 went out at 541 f.p.s. Shot 61 went out at 558 f.p.s. Shot 71 went 555 f.p.s. Shot 81 went 552 f.p.s. Shot 91 went out at 553 f.p.s. Shot 101 went out at 557 f.p.s. and shot 106 went out at 553 f.p.s. I am calling that the end of the useful shots. So Ton Jones’ method of adjusting the top hat got me 106 useful shots on a fill. In the last test that was done in Part 2 where the top hat was loose we saw 87 useful shots. This new method of adjustment gave us 19 additional shots within the useful range. The low for Basics was 511 f.p.s  on shot number 57 and the high was 565 f.p.s. on shot number 80. That is a spread of 54 f.p.s. for this pellet. I think that spread is too high, but I’m not yet ready to make that comment until you see the remainder of the test.

Off the regulator

Shot 107 went out at 576 f.p.s. and I felt the rifle was off the regulator. BUT  — look what followed. Shot 110 was 565 f.p.s. Shot 120 was 565 f.p.s. Shot 130 was 566 f.p.s. Shot 140 was 607 f.p.s. Shot 150 was 595 f.p.s. shot 160 was 559 f.p.s and I stopped shooting at shot 169, which went out at 515 f.p.s. The rifle began loosing velocity steadily after shot 143, which was a Basic pellet moving at 621 f.p.s. 

What I’m saying is although I called shot 107 as the point where the rifle fell off the reg, there were still 62 more shots that were fired! I think I need to tweak the top hat setting just a little, now that I know how it’s done.

That being said, I think I can now turn my attention to the accuracy of the rifle. The reason I did not test accuracy today was the rifle slowed down radically while I was shooting a group, due to the top hat turning. That isn’t happening anymore. I do feel that there could be 70-80 good shots in this rifle at around 570 to 580 f.p.s. with Basics, if the top hat is adjusted better. I would like to see the rifle fall off the reg and not have so many powerful shots remaining.

The pressure remaining in the reservoir at the end of today’s test (169 shots) was 800 psi. At the end of the velocity test in Part 2 there was also 800 psi remaining, but I only got 101 shots in that test and the starting and ending velocities with Basic pellets were very similar. Those two tight-fitting 007 metric o-rings are what made such a dramatic difference.

One last thing

Remember that picture of the o-rings under the top hat that you all didn’t like? That picture was taken BEFORE the velocity test in Part 2. Look at my 007 o-rings AFTER 169 shots in this test.

Edge 007 rings
After 169 shots the 007 o-rings are still in perfect alignment. That’s because these rings have a smaller inner diameter and squeeze the valve stem. Remember — they do not determine velocity. They just control how much air is wasted with each shot.
This picture was taken before my “Oh, phooey” realization below.


Coaches of junior marksmanship teams who have shooters with Edge target rifles need to pay attention to this report! This stuff is brand new and hasn’t ever been seen before. Setting up the top hat this way will significantly increase the shot count that your competitors get from a fill.

I think I can adjust the top hat out a little farther and increase the average velocity a little while also improving the shot-to-shot consistency. I don’t think I need to disassemble the valve or regulator to do this — just tweak the top hat a little more. I’m not sure of it though, and this report has taken me a very long time to create, so I’m finished for now. Stick with me and we will sort this out.

Oh, phooey! I could not stand it not knowing, so refilled the rifle to 3,000 psi, then rotated the top hat one revolution more out from the valve body and shot a final string of Basics. The first shot was 596 f.p.s., but with this Edge every first shot after a pause of some time (I had waited about 30 minutes) is abnormally high. The next 10 shots averaged 575 f.p.s. The spread went from 571 to 579 — a mere 8 f.p.s.

I will have more to say about this in the next report but, by golly, first I’m going to shoot some targets! I probably need to do another velocity test at some point. Maybe I will finish the air that’s in this tank and record the numbers but hold off on the velocity report until we have some targets to look at. We shall see.

100 thoughts on “AirForce Edge 10-meter target rifle: Part 3

  1. B.B.,

    Oh, phooey indeed! That last shot string is very intriguing with its tighter spread and higher velocity. I see a Part 4 (velocity and shot count redone) and Part 5 (accuracy) for this rifle at least. Maybe a Part 6 where you go for 25 yards.

    Ton Jones seems to have worked out how to fine tune the valve for the regulator without needing to replace the springs.


    PS: Section Shot count Second paragraph “So Ton Jone’s (Jones’) method of adjusting the top hat got me 106 useful shots on a fill. In the last test that was dfone (done) in Part 2 where the top hat was loose we saw 87 useful shots.

  2. B.B.,

    I’m beginning to see an Edge in my my future and perhaps two for my Grandsons!

    MATH Check:

    “RWS R10 Match Pistol
    The third pellet I tested was the RWS R10 Match Pistol pellet. Ten of them averaged 554 f.p.s. The low was 539 and the high was 567 f.p.s. So the spread was 18 f.p.s.”

    Looks like ES is twentyeight feet per second (28 fps) to me!

    Small typo in: Shot count, second paragraph, 5th line or so…

    Don’t know what to do with a DFONE? Call me ;^)

    “So Ton Jone’s method of adjusting the top hat got me 106 useful shots on a fill. In the last test that was dfone (done) in Part 2 where the top hat was loose we saw 87 useful shots.”

    Great report! Looks like my tune the valve first off of the Regulator idea works for the Top Hat Airforce System a bit different because of the Top Hat concept compared to a typical PCP valve. The Quackenbush style entire reservoir valve is even different then the separate contained valvebody used in many other PCPs. Seems like design divergence is happening in the PCP powerplant design world! Interesting…very interesting.


    • Shootski,

      If you do not buy any other air rifles in your life, you should buy an Edge. There is nothing like it. These little air rifles are awesome! you may not be able to win the Olympics with one of them, but you will not lose by much. You would also be hard pressed to find a better mini-sniper.

      I so miss mine. 😉

    • Yogi,

      The world of airgunning, though growing, is still pretty small. Those who want shot counters are really few and far between. Why invest in something that the vast majority is not interested in?

      • You don’t know what they want till you give it to them!
        I differ on the statement that “those who want shot counter are few and far between”. I remember when people said that airguns did not want scopes! Droopy barrels are no big thing…

        PS If manufacturer would add it, I bet they ALL would in a very short period of time.

        • Yogi,

          Diana has had them for years.

          Most manufacturers play “follow the leader”. “What is selling hot? Can we make it?”

          A few “listen” to what the customers are saying they want.

          A very few take the customer seriously and if they hear enough demands, they supply.

          To change even one small part on a production line is a major event with most companies. These companies need to have a warm, fuzzy feeling that this minor change is going to increase their profit margin or it is not going to happen.

          How many other airgunners do you hear clamoring for shot counters?

          • I only hear B.B. praising the virtue of PP PCP’s.
            I believe that these are sold rather than bought.
            Most manufacturers, don’t know what they don’t know…


    • Yogi,

      While your idea has some merit,… have you looked up what is available for counters these days? Maybe do so and get back with us. I think we all are familiar with the small silver ones with their little black arm. While a bit bulky, the bolt or lever would be able to activate it. It should even work on a break barrel.

      If I were to guess,.. there is probably some that use laser eyes and mark a count when the beam is broken.

      Look ’em up Yogi and get back to us with some ideas.


      • Chris,

        the only ones that I see are either apps or sound measuring devices. It would need to mechanical and activated by the bolt or lever as you mentioned…Why have an odometer in your car?
        Having a ressetable mechanical counter can’t be that hard to figure out!

        PS If the darkside is going to tempt me it is going to have to offer what I want!

          • Yogi,

            Daystate has already done that on some models in the past (current?). Some love them and some hate them. A bit delicate from what I gather when cleaning and removing the barrel with fine wires and such,.. plus debris/dust fouling the “eyes”. If not mistaken, the reading comes back to a screen like on my Red Wolf. Nothing really to see or that looks like an add on. The RW does not have that chrony feature.


        • Yogi,

          Despite your usual reasonings for not going PCP,…. is a shot counter the only other thing that is preventing you from taking the leap into the dark abyss?


          • Chris,

            I do not quite understand why B.B. has to wait for the regulator to fill? The guy at my range who can shoot an entire magazine in under 10 seconds is impressive…Shot counter, lever on left side, one MOA or less accuracy, five year guarantee, pressure gauge that does not force you to point he barrel at your head. Off the top of my head, that is it for now. Give me more time and I will add to the list.
            Just wondering Chris, how many airguns do you own?


            PS are you now going to try and sell me one of yours. Many of the guys at the range seem to cycle through $$$ worth of gun every 6 months or so. I would want a forever gun. My springers are forever guns.

            PPS-FWIW I had my first car for 11 years and my second one for 15 years…

            • Yogi,

              Not a bad list there! 🙂 Many of those concerns are already addressed by some makers.

              I have a .25 M-rod (RAI stock), .25 Red Wolf, .22 Maximus, 499 bb “rifle”, 75th Red Ryder and a 2240 CO2 pellet pistol.

              Trying to sell you one of mine? Not really. Not opposed though. I would like to sell the M-rod. It would be a STEAL for whoever got it (but I would have to tally up what is in it and then discount from there). The best it has ever done is 13/16″ at 100 yards for 7 of 10 shots. Never have been able to do it again though. 🙁


                • Yogi
                  Don’t you count your shots when you do a 5 or 10 or 20 shot group?

                  I always count my shots. Even when I rapid fire plinking. And to say I’m pewrrt darn good at it.

                  So here’s a question. Why do PCP’s only need a ahot counter?

                  • When shooting my springers, if I don’t set aside either the 5 or 10 pellets that I want to shoot for a group, I do loose track of what # pellet I am shooting.

                    Yup, can’t count pellets, practice the artillery hold, concentrate on the scope, work out my dope sheet, adjust for perceived wind, make sure my back stop is safe, wait between heartbeats; all at the same time. To much for this simpleton!


                    • Yogi, Yogi, Yogi

                      But that’s what you do when you shoot a gun. Not only springer’s but firearms and PCP’s.

                      Well some people anyway. For some its natural. Heck they don’t even think about that stuff. They just all of sudden realize they done it after hitting the bullseye. 😉

                    • Yogi, back in 2012 or so, afew airsoft companies built copies of the M41A pulse rifle used in the movie Aliens, it had a round counter, that counted DOWN from 99 to 0. to simulate the magazine being emptied of its 99 round capacity.
                      The problem was, the magazine had a 180 round capacity, thereby really nullifying the round counter to being a novelty.

                      It worked by having an optical sensor at the end of the barrel that read the BB as it passed. Similar to the Tracer units that are used by some airsofters.
                      Several other companies made the displays and boards for DIY people to make their own.

                      I am sure one of these boards can be modified to count up, or some DIY people could make up something.

                      But with how dirty some pellets are, how long they read the passage of the pellet is questionable.
                      And you have the force of the muzzle blast, or recoil from a springer, that could cause issues with the electronics, or build quality.

                      And then there is the cost.

                      Having a counter that is mechanically actuated bu the bolt is a possibility, but it can not sense if you cocked it to dry fire, or short stroked it, or double fed a round from the magazine.

                      The simplest way, and the least expensive way would be to mount a manually operated counter on the scope or scope rail, that you MANUALLY pushed a button to advance the counter every time you loaded a pellet.

                      A Tally Counter is available online for less than $10, and could be mounted on the gun.

                      Just like taking off an automatic safety, Load a pellet, tap the button, and shoot.
                      You can mount a picatinny mount to it, or sling swivel stud mount, or some other mounting option, or hang it from a lanyard around your neck.

                      Here is a photo of one, with an american quarter for size reference.

                      The knob on the side is used to reset the 4 digit counter.


            • Yogi,

              As for the regulator needing to wait before the next shot,….. as you are here everyday, you will remember that it can be 1) a poor design/set up,… 2) it needs a bit of “breaking in”,… (which I do not like),…. and 3) in some cases a plenum has been added post regulator to store extra air capacity.

              It comes down to proper R+D and quality control of components and assy. procedure. After that,… a decent factory test is in order. Done. Ship it. Do less at your own business’ peril.


            • Yogi,

              “I would want a forever gun. My springers are forever guns.”

              You can in fact have a forever PCP Yogi! I believe my Quackenbush Air Rifles and Pistols with routine basic care will be as close to Forever Guns as any of your spring piston powerplant guns. They aren’t even all Big Bores! I have a few that are .25 caliber and one that is bulk CO2!

              Of course i have currently two nineteen year old cars, a SAAB Viggen and a SAAB 9-5 AERO with well over 100,000 on the Odometer. I wish i still had my 1994 SAAB 9000 Aero 5 door that had 1,000,000+ miles on it. Just no need for three cars for the two of us so i sold the 9000 this past year (do the math you don’t have enough fingers and toes) to a young mechanic to be the basis of a race build. All my cars have retained their original engines and TURBO. I learned all about the care of mechanical things flying and running maintenance on airplanes that were older than me!

              You KNOW you could live with a DAQ Yogi!


                • Yogi,

                  I hope you loved the SAAB 99! I loved my 99s and all my 900s (Old 900) a SPG and a 1988 5 door TURBO 16V we used for 9 years in Europe. I did have a Weisach Porsche and a Fiat 131 Mirafloria Ralley, an Alpha Romeo Giulia and a’55 Chevy before I got smart and learned about On the Roof Carlson!


                  • What Weisach Porsche? I got a 968 2 years ago…
                    Key was always in a strange place. Family car that learned to drive on was a ’72 99 with the Truimph engine. That car you could turn by yanking on the hand brake and turning the wheel. My older brother wore out a 40,000 mile set of Michelin radials in under 10K miles…


                    • Yogi,

                      A 1975 1/2 Porsche 924 Martini special edition which was built at the Weisach Track Motorsport garage.

                      The key on the hump is in all SAAB cars except the 9000 model because that body was shared by SAAB and Alpha Romeo and AR wanted it on the steering column.

                      The dual handbrakes on the SAAB 99s was for driving on ice and packed snow! I never wore out tires doing rear breakaway turns. Made power on turns a blast on snow and ice! You could get kits to turn VW handbrakes into duals!


  3. BB,

    I was wondering what you had done to that Edge?! The spreads were incredible. If you jump into your Wayback Machine to 2010 you will see in part 3 where you shot over 100 shots with a spread of 12 FPS. Even with all of the ‘hot rodding” that was done, I was getting a pretty tight spread.

    Now it is getting back into shooting trim. We should start seeing targets like in 2010. That is why I had to have an Edge.

  4. BB,

    Good report. Way to go!!! with all of your detective work. I am glad you got the o-ring thing sorted and are making good progress with getting the shot to shot spread tighter. After seeing high 20’s,… I said to myself,.. no way would accept that.

    Looking good,…. Chris

  5. Michael,

    “There existed VERY briefly, and it’s no longer in their catalogue, a CO2 (steel .173-174 bb) Mauser by Gletcher done as a companion to the carbine-length (sawed off Obrez) M1944 Mosin Nagant. It was never imported to the U.S., and I can’t find a photo of it easily, but it briefly existed, a CO2-fueled unicorn. :^)”

    There was also in recent times a CO2 SMLE that was also not imported into the USA. Probably because they could not have made enough of either.

  6. BB
    Glad you got some info on the top hat and o-rings.

    And just to say. The 2 Talon SS’s that I have had in the past I put 1 o-ring behind the top hat. I did some searching back at the time I had them and found that people was using the o-ring as a anti-bounce device for the valve. That way the gun didn’t use extra air for the shot and the shot string did get more consistent also when chronying the gun.

    And what is funny is my Condor SS top hat was loose and gave me fits when I first got it. The shots would never stabilize with a consistent group. The group was always changing.

    And I sort of adjusted the top hat on my Condor SS like Ton told you to do. I just did it by feel when I contacted the striker to one side. Then locked the set screws down. And to say my Condor SS didn’t really react to the o-ring mod. I think it just flows so much air.

    And a note on the stacked o-rings for a ant-bounce device for the striker. That is exactly what I done with my heavily modded .25 caliber Marauders I had.

    Without o-rings the striker bounces the valve. When that happens its waisted air and it bounces inconsistently. With the o-rings your controlling the bounce if that makes sense.

    Oh and see what happens when you don’t follow a procedure. I’m talking about when Ton set your top hat and the next person didn’t get to do their job.

    Maybe something like that happened with my Condor SS. Maybe that’s why the top hat lock down set screws were loose on it. Anyway after got that straightened out my Condor SS is a very accurate gun.

  7. Chris,

    Give it up.

    The other day Yogi said he was a hardcore sproinger dude.

    You could offer him a PCP with every bell and whistle he can think of and then some and offer to sell it to him for $150 and he would say “If I could get it for $100, I might take it.”

  8. Just so you know, you guys who have a Maximus air rifle had best hang on to them. It seems that they are going the way of the Discovery. Right now to get one it is a special order item. Basically they will build one when you order one.

        • Shootski,

          1/10 of 1%? or 10%?,… (0.10%).

          Either way,.. Yogi is a pretty hard sell on the whole PCP thing. While focused on gun this or that,… I think the biggest issue is the pump and tank cost. Once I decided to go PCP,… the Shoebox and oil-less compressor and small tank were a given cost I was resigned to. After that,… there is more than enough choices in guns to pick from. No regrets.


          • Chris,

            1/10th of 1%

            I understand Yogi’s stated position.

            He could surprise us since he is obviously intently listening.
            At some point he may find that he can’t come up with a good reason not to buy one and a way to fill it! But i hope he is having fun along the way with whatever he shoots.


  9. I have a question for any you out there using a hand pump to fill your PCPs. Recently, when I was filling my Urban, the pressure gauge on my hand pump indicated that the pressure was not holding. I could hear a slight hissing noise coming from the fill probe area. Upon further investigation, I discovered the leak was coming from the female quick disconnect fitting. When I looked inside of the fitting I noticed some small red pieces of rubber. Using a toothpick I removed the red o-ring which appeared to be damaged, with pieces coming off from it. Then I discovered a second black o-ring that was located behind the red one. This does not seem normal to me. I do not understand the reason for the fitting having two o-rings, one on top of the other. I also do not know why the red o-ring is showing abrasion damage. I do not normally remove the Urban’s fill probe from the fitting.
    So, I measured the black o-ring with digital calipers to determine the size. The red o-ring was swollen and distorted so I was not able to measure it. Next, I stopped at my local hardware store to purchase a new (or two) o-ring but they did not have the correct size. I also checked Home Depot and TSC but no luck finding the correct size o-ring. I came home and went online and did some research. The black o-ring did not conform to any of the standard metric or SAE o-ring sizes. Neither could I find anywhere indicating the size of the female quick disconnect o-ring. I finally just ordered an o-ring designated as being for the inside of the female quick disconnect fitting for airsoft or PCP. I had to order a lot of 25 pieces though. Here is a photo of the two o-rings.

    • Geo,
      First out of a concern for your SAFETY!
      How much pressure are you putting through that Brass QD? That is almost certainly a low pressure QD. IF you are using that for typical PCP pressures it should (if it is of commercial manufacture) have an FSS stamped on it and almost certainly fabricated out of Stainless Steel.
      More soon as the Rioters have moved on.


        • Michael,

          I don’t understand your comment. We had some rioters (not peacefull protestors) go by our neighborhood. I couldn’t research Geo’s question and keep an eye on them too!

          What is your issue with that?
          It is for now the Newest NORMAL unfortunately where I live.


          • Shootski,

            Well that stinks, I hope you and your neighbors took no damage.

            And it kinda answers the question, “why would anyone need a 30 shot magazine?” Can you say 100 round drum mag, sure I knew you could. With the way these clowns are acting you might still be overrun.

            Georgia Governor Brian Kemp said today we will take no hostages, well no he did not actually say that but his words were very stern that we will not tolerate these rioters, and I agree with his stand on this.


            • Mike in Atl,

              They just were moving to some other place to probably break out small business owners windows, loot, and trash someones means of support Just what those folks need just now! So far it seems the plan doesn’t include making residents/home owners upset! I hope it starts raining soon; in the past the weather drives them back to wherever they came from.

              Their behavior doesn’t move us in a better direction!


              • Shootski,

                Sorry you had to encounter that. The bad apples are like a pack of Jackals. They do not care and seem to have no limits.

                Even our small town (20,000?) had a protest Mon. evening. From the on line pics from the local paper this AM,…. it was more than clear that they were not locals. As far as I know,.. all was peaceful, at least in an uneventful way.

                It will be interesting to see what form “cracking down” takes in the next few days. What is happening now can not stand. Meanwhile,… the good apples are getting their free speech rights walked all over.

                Best wishes for uneventful days ahead,…. Chris

                • Chris USA,

                  Be very alert for tactics displayed in the District Metropolitan Vicinity:. Trucks delivering/dumping bricks and other dangerous projectiles to various locations after the curfews. These individuals are hijacking the lawful protestor’s honorable and civil protest.
                  I served for decades, as did my immediate family, to ensure American’s Natural Rights and Constitutional Rights be preserved.
                  Any group or individual who does this EVIL needs to be exposed and brought to justice!


      • Shootski
        That is probably gold anodizing. Not brass.

        I believe I have 2 gold female Foster quick disconnect fittings. They are definitely steel not brass.

      • Shootski,
        See the photos I posted in the reply to ChrisUSA. I agree with your suggestion that a blog regarding HPA fill equipment, and the dangers there of, would be very beneficial to the airgun community.

    • Geo,

      I would agree with Shootski, that could be a low pressure foster fitting and if that is the case the hose could also be substandard. I would advise on replacing the hose and foster fitting as a unit.


      • GF1
        I agree with you. The black one appears to be in good condition and fits into the bottom of the fitting well. I did reinsert that o-ring and then used the plug to check the pressure. The QD coupling does not hold pressure with just that one o-ring though. ???

          • GF1
            I put silicone grease on the o-ring before reinserting it but when I tried the hand pump I could hear the air escaping past the o-ring. Without that second o-ring, pressure would not build at all. I have new o-rings on order and they should be here later this week. We’ll see what happens then.
            I do put a couple of drops of RWS silicone oil in the fill probe occasionally to lube the Urban’s internal seals, as recommended by some of the guys here in the blog. Thanks for your suggestions and I appreciate your response to my questions.

            P.S. see the photos I posted of the HPA whip injury. People do need to understand the danger of HPA.

            • Geo
              My next suggestion was going to be silicone grease. That should seal it up.

              It sounds like it just had the wrong o-ring for some reason.

              And I know about hose whip. I seen it when a 150 psi shop compressor at work blew. The guy that was using it had welps all over his side and back before he pinched it off.

              And on my first china compressor I guess I didn’t click the quick disconnect up far enough when I put it on the male Foster fitting. It blew off at about 2500 psi. It had a big 3″ long by about 1-1/2″ diameter dryer filter attached by the quick disconnect. It flew up with a very loud pop and hit the corner of the red brick wall behind the compressor. It took a good 1″ chunk out of the corner of the brick. If it would of been over to the left about 2 more inches I would of been putting a new window in the breezeway going to the house. After that I started holding the quick disconnect on the Male fitting while my other hand was ready to push the compressor stop button. And I totally make sure I fully click the outer part of the quick disconnect all the way forward while pushing it on the male fitting.

              And yes always make sure your hoses and fittings are good. I used a gun so much that it started rolling a burr out all the way around where the balls in the quick disconnect are suppose to catch the outer diameter of the male fitting. It was actually starting to get rounded from so much use. I could watch the quick disconnect snap out away from the male fitting about a 1/16 of a inch. Not good.

        • Geo,

          Lot’s of good advice. I know when I got my set up from Joe Brancatto (sp?) and spoke with him on the phone,…. sub standard fittings and hoses are very common.

          Good luck on getting it back up and running soon. Squirrels have become scarce around here. 😉


          • Hey Chris,
            I have read about some questionable HPA equipment too…especially coming from China. At least with a hand pump the body parts are somewhat clear of the fill hose and fittings. It would seem that the volume of air under pressure would be quite small in comparison to a tank or compressor. So it that regard, maybe not quite as dangerous?
            I do understand the dangers of high pressure air. A fellow airguner sent me photos of a guy he knows that had the fill hose explode on a HPA compressor. I guess he does repair on them. This poor guy was really torn up by it. Another problem is that the equipment was manufactured in China so there was no legal recourse. This is a very good example of the dangers of HPA.

                • Chris USA,

                  If he was using 4,500 PSI in those metal braid armored hose i can see that much damage. As soon as the micro bore plastic hose came to market i retired my old hoses immediately! The MASS of the micro bore is so much less and the amount of energy istored n the hose so much less that it was a NO BRAIN’R (pun intended) for effect! The other item often left out of fill systems are check valves and flow reduction orifices.


  10. Geo,

    I’m back. I don’t know the manufacturer of your QD but on low pressure one O-Ring can be used as a seal and the other (perhaps the red one) holds the balls under tension to lock the two parts of the QD together. Most of the 3,000+ psi ones that I have use a metal spring to hold the locking ball(s) into their cutouts.

    Start your reading here: and here:

    and then go from there to the specifics for your application. Only as an example: you will find fittings and fill hoses and more for our very high pressures.

    This could be one for BB to cover.


    • Shootski
      Thank you for the information. This QD and whip are from my Taousa HPA hand pump rated at 4500 psi. There are many of these HPA hand pumps on Amazon and ebay. I bought this one two years ago to fill my Gamo Urban which has a fill pressure of 232 bar. I only fill to 2900-3000 psi because that pressure results in an extreme spread of only 20 fps over 25 shots. No, the red (silicone) o-ring does not hold the balls under pressure. It’s a seal at the bottom of the female QD fitting and just seems to be disintegrating.
      If you look at the Benjamin hand pump here in the Pyramyd Air web site you will see that it also has a brass quick disconnect fitting.

      • Geo,

        I guess in the early days designs must have been different…the rule was Fosters in SS with the FSS stamp were the only ones to use.

        I hope you can order a replacement from a reliable source. Micro bore hose saves pressure losses and volume but you probably already know that.

        Hope your fill system is up soon.


      • Geo,

        “I only fill to 2900-3000 psi because that pressure results in an extreme spread of only 20 fps over 25 shots”

        ?,…. did you get a chrony or are you just going off of published data?


        • No, I did not buy a chronograph. I don’t plan on making any hammer spring adjustments so I think I can get bye without one…at least for a while. I gleaned the optimum fill pressure from Steve Scialli at Airgun Nation and Tyler Patner. When B.B. reviewed the Urban in part #2, he also found the best fill was 3000 psi. Above 3000 psi the hand pump becomes much more difficult to pump. I fill to 2900-3000 after two mags, 20 shots and that works fine for me.

  11. Everyone, FYI
    I fixed my hand pump this afternoon. I was going to do a workaround by putting the damaged o-ring back in, but on the bottom, then insert the black one that was on the bottom, on top. This was just to get bye until the new o-rings arrive. I needed to fill the Urban for pesting and then it should be good for the rest of the week.
    Well, when I was looking through the zip-loc bag of spare parts I discovered that there was a spare female QD in the bag! There were two black (Buna-N?) o-rings inside of the spare so I removed one of them and used it to replace the damaged red o-ring. Yes, there are two o-rings stacked on top of each other by design. I put some silicone grease on the o-rings and lubed the pump with some silicone oil. I inserted the test plug and pumped up to 3500 psi. The pressure held steady and I’m back in business. I don’t know why a red silicone o-ring was used in the female QD. They are too soft and do not hold up to abrasion well. I should be good now for a couple more years. 🙂

      • Chris,
        For sure! I have three bluebird nesting boxes in my back yard. On Sunday I inspected all of the nesting boxes. Box #3 had bluebird eggs in it and bluebirds had already fledged out of box #2. Yesterday I saw a sparrow with it’s head poking out of box #3, oh no! The sparrow flew out and I went out to check that he hadn’t caused harm. The nest was empty and no eggs! Grrrrrr. I watched and a few minutes later the sparrow came back and went into box #3 again…bad decision. I got the Urban out and braced on the corner of our screen room. When the sparrow stuck his head out again, I don’t want to be too graphic but you know what happened next. The sparrow fell out of the box to the ground and the bluebird immediately flew down to engage him. He looked at the dead sparrow for a minute and then flew off, wondering what had happened to the sparrow. Well, that sparrow will not be harassing the bluebirds any more but it’s just too bad I didn’t catch him sooner before he destroyed the eggs.
        And that’s why I have the Gamo Urban, to protect the bluebirds. I was rather proud of that 30 yard head shot, if I do say so myself. I have missed quite a few too though. They just don’t give me enough time, and I have to take a hurried shot. I have to watch those nesting boxes like a hawk.

        • Geo,

          Glad you solved the issue with your QD!
          Keep up the good work!
          Maybe you could force yourself to settle for center mass shots instead of headshots on sparrows…you can always do a follow-up.

          Just call them bowtie shots if they are males!
          I suspect most of your problem birds are female sparrows!


          • Shootski,
            I normally do shoot for center mass, but this sparrow only presented his head, and it was a male. Same with the grackle yesterday, he stood on my cardinal feeder so that I wasn’t able to shoot without risking a pass through and damaging the feeder. He finally moved enough that I could take a clear head shot. I have been leaving the grackles alone as long as they stay off from my feeders.

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