by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3

This report covers:

  • The test
  • Sight in
  • Falcon group
  • Discussion
  • RWS R10 Match Pistol pellets
  • Discussion 2
  • JSB Exact RS dome
  • Discussion 3
  • Second group of JSB Exact RS
  • Third group of JSB Exact RS
  • Summary

Today I mount the 3-9X40 Gamo scope and shoot the Fusion 10X from 25 yards. It will be an interesting test.

Mounting the scope

The scope that’s bundled with the rifle comes with a one-piece mount already attached. All you have to do is loosen the three Torx screw on the scope mount base with the wrench provided and clamp the mount to the 11mm dovetail base on the rifle. The mount has a scope stop pin that fits into the rear hole in the base and locks the mount from moving under recoil. I had the scope on and ready to go in 10 minutes.

The test

I shot off a rest at 25 yards. I used pellets that showed potential in Part 3’s test with open sights, except I had run out of H&N Match Green pellets, so I substituted something else.

I shot with a modified artillery hold, since I learned in Part 3 that the rifle likes that best. I actually modified my hold as the test progressed and I will tell you about it as we go. Let’s get started!

Sight in

I sighted in from 12 feet with Air Arms Falcon pellets. The first shot hit the paper at my aim point, which means it will climb higher as I move back, so I backed up to 10 meters and fired a second shot. Shot two was higher and also to the left. It was close enough to the aim point that I backed up to 25 yards to refine the sight picture. It took a couple more shots to get the rifle shooting where I wanted and then I fired the first group. While most of my groups today will be 10 shots, this first one was only 5 because I was also testing whether loading single pellets or loading all 10 into the magazine worked best.

I’m not going to show the first 5-shot group because it overlapped a couple sighters and isn’t easy to see. But now I loaded the magazine with 10 of the same Falcon pellets and shot a group.

Falcon group

The ten-shot group of Falcons was revealing! It was looking to be a good group until the final four  shots. The group grew from 0.475-inches between centers to 1.554-inches. 

Falcon group
Ten Falcon pellets went into 1.554-inches at 25 yards. The first 6 of them are in 0.475-inches.

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Before we move on I need to tell you what I think is happening. First, I believe the hold is the most essential part of accuracy with the Fusion 10X. Unfortunately it has a thumbhole stock that cannot be held as loosely as I would like, but a loose artillery hold is a key to the rifle’s accuracy.

Next, I don’t think there is a large difference between loading pellets one at a time and loading the entire 10-shot magazine. And the way the Fusion 10X works, using the magazine is certainly easier. I finished the test shooting from the magazine.

The scope is reasonably clear at 25 yards. I adjusted the eyepiece until the crosshairs were sharp through my everyday glasses, and I could see them on top of the 25-yard bullseyes.

For a bundled scope this one isn’t bad. And the fact that it comes with the mount already installed on the scope is a plus for those who don’t like mounting their own optics.

Finally, I don’t believe that Falcon pellets are necessarily the best in this rifle. I will try some other types. I did not adjust the scope after this group.

RWS R10 Match Pistol pellets

Next to be tried were ten RWS R10 Match Pistol pellets. These landed low and left of the bull. The group measures 1.397-inches between centers and once more there is a tighter cluster of five in the center of the group. There were not shot in succession, but for each of them I was extra-careful to hold the rifle lightly. Now I am learning something!

R10 group
Ten RWS R10 Match Pistol pellets went into 1.397-inches at 25 yards. The aim point was the bullseye at the upper right.

Discussion 2

Okay, I think I have it figured out. The Gamo Fusion 10X is very sensitive to how it is held. It is also pretty accurate, but only when the hold is right. The pellet probably does not make as much difference as it will appear in this test, but I did move on to the JSB Exact RS dome.

I also believe that feeding pellets from the magazine does not detract from the accuracy. Maybe I’m talking ahead of my test results now, so let’s move on and I will show you.

JSB Exact RS dome

I had left the scope adjusted where it was after my first 5-shot group and both the second and third 10-shot groups and now I could see the Fusion 10X was shooting too low and left. So I adjusted it 5 clicks up and two to the right. Ooops! Should have waited to shoot the JSB Exact RS domed pellets first. Because the 10 JSB pellets landed to the right of the bull. The elevation seemed correct but the windage was off to the right.

Ten JSB Exact RS pellets went into 1.046-inches — BUT only the first three shots are high and horizontal. I then slid my off hand out to the end of the cocking slot and shot the next 7 shots into a group that measures 0.648-inches between centers. For 25 yards that’s not that bad! In fact this group was so impressive to me that I drew a circle around the last 7 shots, to separate them from the first three shots.

RS group 1
The first group of 10 JSB Exact RS pellets went into 1.046-inches between centers. The final 7 shots that I really concentrated on are in 0.648-inches, which is inside the circle.

Discussion 3

You must be wondering why I couldn’t REALLY concentrate on the first three shots, if I knew what was happening. Let me explain. When you shoot with the artillery hold there is a final step that is sometimes critical, and other times not. Before you squeeze off the shot you close your eyes and relax, then open your eyes and see where the crosshairs are. If they have moved from where you want to hit, you make small adjustments of your hands and elbows and then do it again. You keep doing it until the crosshairs are still on target after you open your eyes. Then you take the shot.  This takes time and a LOT of concentration, but as you shoot a rifle more and more, it starts to become second nature.

It takes a lot of concentration for every shot, but I can do it when I have to. And with this rifle it seems necessary.

Second group of JSB Exact RS

JSB Exact RS pellets seemed like a good pellet to test, so I adjusted the scope three clicks to the right and two clicks up and shot a second 10-shot group. I did my very best this time and 10 JSB Exact RS pellets went into 0.959-inches at 25 yards. That’s not enough different from the last group to say much of anything.

RS group 2
The Fusion 10X put 10 JSB Exact RS pellets into 0.959-inches at 25 yards. This group is a little more to the left and a little higher, but not much!

That was the best I could do. But my conscience still argued that I should have done better. I was tired but still functional, so I shot one final group. This time it was just five shots. I figured I could hold it together that long. I adjusted the scope up two clicks and right three clicks.

Third group of JSB Exact RS

This time I pulled out all the stops on each shot. And it worked! I was able to put five pellets into a group that measures 0.495-inches at 25 yards. To tell the truth I wanted to shoot a second five shots, but I was concerned I wouldn’t have anything to show you. Other airgunners shoot five shot groups as a matter of course, so there you are!

RS group 3
The Fusion 10X put five RS pellets into 0.495-inches at 25 yards.


The Gamo Swarm Fusion 10X GenII repeating pellet rifle is a remarkable airgun. It is smooth, accurate and has a reasonably nice trigger. Its GenII 10-shot magazine lies flat for a low profile, yet the rifle feeds very reliably. It’s easy to load and even easy to fire single-shot without removing the magazine.

This gas spring-powered breakbarrel rifle is easy to cock. It’s not a mega-magnum by any stretch, but it’s a good honest .177 that develops almost 15 foot-pounds. Yet I can cock it easily with one hand.

The rifle is lightweight, yet does not vibrate or recoil very much when it fires. And all of this comes to you with a scope for under $300. Gamo has done very well with this one.