AirForce Edge 10-meter target rifle: Part 3
by Tom Gaylord
Writing as B.B. Pelletier
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
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.
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.
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.
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.
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.
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.
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.