Diana 27S: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Diana 27S
Diana 27S.

Part 1
Part 2

A history of airguns

This report covers:

  • SHOT Show
  • Odd-sized breech seal
  • Grainger
  • Velocity with Air Arms Falcon pellets
  • Fooled around
  • WHAT!!!?
  • On with the test — JSB Exact Heavy
  • Chronograph error
  • Cocking
  • 27S
  • Cocking behavior
  • Firing behavior
  • RWS Hobby
  • Summary


I’m at the SHOT Show today. Today is Media Day At The Range, so I’m looking at all the new airguns that are on the range in Boulder City. Yesterday I went to Sig Range Day, so tomorrow I will have a report on both events. The show opens on Tuesday, so the Wednesday blog will be my first report from there.

Today we look at the velocity of the Diana 27S we are testing. If you recall, in Part 2 the breech seal failed and I couldn’t test the rifle. I replaced the seal with a temporary leather one and the velocity jumped from the mid-300s to the high 600s. I said then that it was the largest velocity increase I have ever seen from just replacing a breech seal. I expected a gain of 60-80 f.p.s. Several readers made similar comments.

Odd-sized breech seal

When I measured the old seal I expected to find numbers that were even, numbers that made sense! Instead I found the old seal’s material diameter (the thickness of the ring) was 2.4mm. The inside diameter was 8.3mm and the outside diameter was 13.1mm. Okay, where is the camera — I’m on Candid Camera, right? I expected a ring with a thickness of 2.5mm, an ID of 8.5mm and an OD of 13mm. Who would make something common like an o-ring with such random and odd dimensions? The ring wasn’t designed for Diana. Diana selected the ring from what was available and designed their airguns to fit.

Apparently, though, someone did design a ring like this because when I went to Grainger looking for one, there it was — 2.4mm by 8.3mm by 13.1mm! The reason I was so skeptical is because when it comes to measuring things I’m a cut-three-times-measure-once-and-then-hire-somebody-else-to-do-the-job kinda guy. But, listening to all of you guys with skills, I figured I could at least give it a go — might provide some fodder for a funny blog!


So I placed an order with Grainger for 25 o-rings. I have about 6-8 Dianas that need these seals, and the way I love these guns more can come at any time. The rings arrived last week, and, with considerable trepidation, I installed one in the 27S. Then I set up the chronograph and fired the first tentative shot.

Diana 27S breech seal
The new o-ring/breech seal from Gainger fit perfectly.

Velocity with Air Arms Falcon pellets

Okay guys, we will start the velocity test with the Air Arms Falcon dome pellet. Ten Falcons averaged 689 f.p.s., for an average muzzle energy of 7.73 foot-pounds. Remember — the magic number of 671 f.p.s. is the velocity at which the energy of the pellet in foot-pounds is equal to the pellet’s weight in grains.

The spread ranged from a low of 672 to a high of 710 f.p.s. That’s 38 f.p.s., which is high.

Fooled around

After that I shot some more Falcons and got a string of three that measured 320, 309 and 310 f.p.s. — WHAT!!!?


Right after installing the new breech seal and shooting the gun at velocities in the 690s, I suddenly got one at 374 f.p.s. And that is when it hit me. The new breech seal DOES NOT add 300 f.p.s. to the velocity of the rifle! I had shot through the chronograph in such a way that the first skyscreen was triggered at the wrong time. I know that because I can now do it anytime I want.

It isn’t common but I have seen this phenomenon before. If the muzzle of the gun is too close to the first skyscreen (with Shooting Chrony chronographs) you will get a reading like this. In the case of this Diana 27S I also have to point the barrel slightly downward by a few inches at 3 feet to make it happen every time. That is what happened in the last test, but I didn’t catch it until today. It was just the way I was sitting that made it happen. Apparently the Diana 27S is just long enough to put the muzzle in the exact right spot for this to happen.

So — chronograph users beware. And everybody — a new breech seal should not increase velocity by 300 f.p.s. unless there was no seal to begin with!

On with the test — JSB Exact Heavy

Next up is the JSB Exact Heavy pellet. At 10.34-grains this dome is on the heavy side for a rifle of this power but I have seen excellent results from such pellets in weaker airguns in the past. Ten JSB Heavys averaged 555 f.p.s. from the 27S. The spread went from 552 to 560 f.p.s., so a difference of just 8 f.p.s. At the average velocity this pellet generates 7.07 foot-pounds at the muzzle.

Chronograph error

I got two “Error 2” messages on this string. That message means that skyscreen 2 isn’t seeing the pellet. This is something I am familiar with. Unless the pellet missed passing over the skyscreen it means something has fallen onto the widow above the screen’s sensor. As close as I shoot I knew I wasn’t missing the screen, so it had to be an obstruction. When I looked I saw exactly what it was and was able to clean the screen and get going again.

Diana 27S skyscreen
I shoot with the chrono so close to the pellet trap that stuff sometimes falls on skyscreen 2. There is a smashed lead pellet on the left and a large piece of paper on the right. Remove all the stuff and wipe the screen window with a cotton swab and you’re back in business!


I reported in Part 2 that the 27S cocks with 24 lbs. of effort. That’s more than I expect from a Diana 27, but this isn’t a 27 — it’s a 27S.


The Brits call the 27S the 27 Super, and apparently it was sold to them under that name. They also know of a 35 Super model that I never heard of. Well, looking at both the cocking effort and just the velocities we have seen thus far I think the 27S is more like the Diana 35 than it is like the Diana 27. In fact, the Diana 35 that I tested and tuned last year shoots at lower velocities than this one.

Cocking behavior

The 27S cocks with a slight scraping noise that is common to rifles that have two-piece articulated cocking links. The solution is lubrication, which I will apply when I go inside.

Firing behavior

This rifle shoots with a jolt and a lot of buzz that isn’t common for the other vintage Dianas I have experienced. I will have a look around inside for what can be done and also to see what that anti-beartrap mechanism looks like. But while I’m inside I will lube the rifle with Tune in a Tube in both the mainspring and ball bearing trigger areas. In fact, I am curious to see whether the ball bearing trigger in the 27S looks like the one in a 27 or the one in the 35 that has a few additional parts.

RWS Hobby

This is the last pellet to be tested. RWS Hobby was the speed demon of its day, which was contemporary with the vintage Diana line we have examined. I have found in recent tests that Falcon pellets, though slightly heavier, are often faster, but we shall see.

Ten Hobbys averaged 660 f.p.s., so true to form they are a little slower than Falcons. However, the Diana 35 that I tuned last year averaged 601 f.p.s. with a 26 f.p.s. velocity spread with Hobbys. Today the 27S low was 650 and the high was 671 f.p.s., so the spread was 31 f.p.s. At the average velocity the Hobby generates 6.77 foot pounds.


That’s it for this report. The new breech seal tells us what we need to know about this rifle — it’s in good condition and probably shooting like it did when new.

I would also like to add that today was a big learning day. We learned or were reminded about some quirks of chronographs that I hope will help some of you.

The next report will be a disassembly and examination of the insides of the 27S. And, if it cooperates, I will give it a lube tune and button it back up for another velocity and firing behavior report to follow. So, stay tuned!

Air Arms Pro-Sport: Part 7

by Tom Gaylord
Writing as B.B. Pelletier

Air Arms Pro-Sport.

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6

This report covers:

  • Disassembly
  • Rotate forward spring guide
  • The washers
  • Factory top hat
  • Last note
  • Assembly
  • Relubed
  • Gun back together
  • Velocity with RWS Hobbys
  • Velocity with Baracuda 5.50mm heads
  • Cocking effort
  • The question
  • Summary

Today we look at the Air Arms Pro-Sport with the Vortek PG3 tune kit installed at its most powerful setting. This test was suggested by reader Yogi in the comments to Part 5.

“To finish up the review, how about exploring the other 2 notches in the PG3 kit? Maybe one notch is full OEM power, second notch is the desired 12 foot-pounds, and the third one(the one you have it set on) is good for 10.5 foot-pounds.

This way you have a full report on the Pro-Sport AND the PG3 kit.”

I though that was a great idea. Unless I test it, who knows what the other notches will do? And also there are the two heavy washers that add weight to the piston and more tension to the mainspring.

What I won’t do is test every possible combination of the kit. Besides the three notches there are two washers, so that’s a possible 9 different combinations to test — low notch no washers, low notch one washer, low notch 2 washers, mid notch no washers etc.

Instead, I will go to the opposite end of possibilities and set the mainspring on the high notch with two washers installed. That will bracket the power possibilities.


The Pro-Sport came apart in a few minutes with no mainspring compressor needed. Remember that with this Vortek kit the pretension on the mainspring is even less than on the factory gun and even that doesn’t need a compressor.

Pro-Sport Vortek kit
The thousand-word picture. The mainspring is in the lowest notch from the previous tune. The two washers from the Vortek kit are going in ahead of the forward spring guide (black thing the mainspring is wound around) that’s inside the piston. The factory top hat is shown below. One of the washers is stuck to the tip of a magnet to show that it’s ferrous.

Rotate forward spring guide

To get the end of the mainspring into the highest notch in the base of the forward spring guide, the spring guide has to be rotated. However, the inside diameter of the relaxed spring is smaller than the outside diameter of the spring guide — so the spring is on the guide extremely tight. It look me 20 minutes of fiddling with a screwdriver to move the guide high enough to make the slight rotation that was needed. You don’t want to grab the base of the guide with pliers because it is synthetic!

After that was accomplished the rest of the job took mere minutes. But before I go there, let’s look at what I’m about to do.

The last tune was with the spring set in the lowest notch of the spring guide. And no washers were used. So the piston was almost as light as it could be. By removing the synthetic spring guide it would have been a few grains lighter, but the spring would then have had room to vibrate on the piston stem. Vibration is a bad thing, so those few grains of weight are well spent.

The washers

I weighed the two washers, which are steel. One weighed 85.5 grains and the other weighs 86.2 grains. When I add that the two should weigh 171.7, but for some reason my scale says 171.4 grains. We are talking about a weight difference of a postage stamp, so it may be more in the technique I was using to place them on the scale than any real weight difference. At any rate, an additional 171.4-grains of weight is being added to the Pro-Sport piston.

Pro-Sport Vortek washers
Both Vortek washers together weigh 171.4 grains. They will be going into the piston ahead of the mainspring.

Factory top hat

For curiosity I also weighed the factory top hat that goes into the piston like the washers. It weighs 352.2 grains, or 180.8 grains more than the two washers. It’s a little over twice the weight of the two washers. That’s interesting but I don’t know why.

Pro-Sport top hat
The factory steel top hat weighs 352.2 grains.

Last note

If someone reads this entire report they will discover that I removed the sliding compression chamber for the first tune in Part 5. I did it because the piston didn’t want to go into the chamber when I started assembling the gun. But it really isn’t necessary to do that. Just fiddle with the piston and the piston seal will eventually clear and go in the chamber. This time I did not remove the sliding chamber and the time to assemble was cut by several minutes.


I won’t show you the entire assembly of the rifle because that was covered pretty well in Part 5. I will just show you the order of the parts as they go back into the gun. The two washers go onto the piston rod first. They add that 171-grains of additional weight to the piston, which should change its performance with heavier pellets a little. They also add perhaps a quarter-inch or a little more of preload to the mainspring.

The higher notch on the spring guide also adds a little preload to the spring. I would guess that together the notches and the two washers add about 3/8-inch of preload. That isn’t much, so Yogi, I doubt we are going to see the factory spec with this kit. I think it may get a little closer to 12 foot-pounds, which is what the specs tell us to expect.

Pro-Sport notch
There is the end of the spring in the highest notch. It isn’t seated all the way but when I cock the rifle it will seat.

Pro-Sport assembly
And here is how the parts go back in the piston and then into the rifle.


Handling the parts during this procedure removed most of the Tune in a Tube that was on the outside of the mainspring, so I added just a bit as the spring went back into the gun. It was still coating the inside of the spring, the rear spring guide and the sliding chamber so I left those alone.

Gun back together

Excluding the 20 minutes I spent playing with the forward spring guide, the job took 30 minutes including pictures. That’s from shooting condition back to shooting condition. It was now time to test the results!

Velocity with RWS Hobbys

In the previous lightest possible tune the kit pushed 11.9-grain RWS Hobby pellets out at an average 633 f.p.s. for 10.59 foot-pounds at the muzzle. With the PG3 tune set to maximum the rifle now launches Hobbys at an average 667 f.p.s. for an energy of 11.76 foot-pounds. The lightest tune gave a velocity variation of 11 f.p.s. This tune gave a range of 16 f.p.s. — from 660 to 676 f.p.s.

Velocity with Baracuda 5.50mm heads

In the previous lightest possible tune the kit pushed H&N Baracuda pellets with 5.50mm heads out at an average 437 f.p.s. for 8.97 foot-pounds at the muzzle. But remember, we added 171.4-grains of weight to the piston besides increasing the mainspring preload. This time Baracudas average 463 f.p.s. for an average 10.07 foot-pounds at the end of the barrel. The spread previously was 10 f.p.s. and this time it’s 14 f.p.s. — 456 to 470 f.p.s.

Cocking effort

The cocking effort felt almost the same with possibly one or two more pounds of effort needed to cock the rifle. On my scale it measured 37 pounds of force required, where with the lightest tune it was 35 lbs. and from the factory 48 lbs.

Firing behavior

I can’t detect any difference in the firing behavior from the previous tune. Recoil seems the same, too.

The question

Should I test the rifle for accuracy again with this tune? It’s bound to be very close to where it was before.

And how should I send the rifle back to Pyramyd Air — with the tune just installed or returned to factory spec? I guess I’m asking whether you think anyone would want to purchase a .22-caliber Pro-Sport that has been tuned to 12 foot-pounds?


I don’t know if this is the last report or not. I’ll await your decision on that.

I have to say I am thoroughly impressed by the Vortek PG3 tune kit that delivered EXACTLY what was promised! With all the variables involved (TIAT and me being two of them) I think it’s remarkable it turned out as well as it did.

Gamo 126 single stroke pneumatic 10-meter target rifle: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Gamo 126
Gamo 126 single stroke pneumatic 10-meter target rifle.

Part 1
Part 2

A history of airguns

This report covers:

  • The test
  • R10 Match Pistol
  • Air Arms Falcons
  • RWS Hobby
  • Sig Match Ballistic Alloy
  • Gamo Match pellets
  • Vogel Match pellet with 4.50mm head
  • Discussion
  • Summary

Today is a day I have waited for for many years. This is the day I discover how accurate the Gamo 126 10-meter target rifle is. Let’s get right to it.

The test

I shot off a sandbag rest from 10 meters. I shot 5 pellets at each target.

R10 Match Pistol

First to be tested and also used for sighting-in was the 7-grain RWS R10 Match Pistol wadcutter. Sight-in took three shots and then came the group. The 126 put five R10 Pistol pellets into 0.314-inches at 10 meters. That’s not a very auspicious start. I expected better from this pellet.

R10 Match Pistol group
Five R10 Match Pistol pellets went into 0.314-inches at 10 meters.

Air Arms Falcons

I often test one or two domed pellets in a target rifle because many readers ask for it. At 7.33 grains the Air Arms Falcon seems like a good choice for my 126 that’s shooting more like a pistol than a rifle. Five of them went into 0.155-inches at 10 meters. Now, the holes left by domed pellets moving at slow speed are hard to measure with accuracy, so this could be off quite a bit, but I was still impressed. It brought out the trime!

Falcon group
The 126 put five Air Arms Falcon pellets in 0.155-inches at 10 meters. That’s not bad!

RWS Hobby

Next up was the venerable RWS Hobby. Hobbys are sometimes quite accurate in lower-powered air rifles, but not in this one. Five made a 0.281-inch group at 10 meters.

Hobby group
Five RWS Hobbys went into 0.281-inches at 10 meters. Another not-so-spectacular pellet!

Sig Match Ballistic Alloy

Next I tried five Sig Match Ballistic Alloy pellets. These were the fastest in the 126 in the velocity test, and today five of them went into 0.218-inches at 10 meters. That’s pretty good.

Sig Match Alloy group
Five Sig Match Ballistic Alloy pellets went into 0.218-inches at 10 meters.

Gamo Match pellets

I searched though my supply of .177 pellets for Gamo Match pellets, but did not find a tin. That’s too bad because I have always felt they are a good target pellet. I put them on my list to order in both .177 and .22. But since the 126 is a Gamo rifle I felt I had to test it with at least one Gamo pellet, so I broke out a tin of Gamo Master Points. This is another pellet that doesn’t cut a round hole in the target paper, but the group was another small one. Just 0.183-inches separated the centers of the two holes farthest apart. The trime was used a second time!

Gamo Master Point group
The Gamo 126 put five Gamo Master Points into a 0.183-inch group at 10 meters. Not bad!

Vogel Match pellet with 4.50mm head

The last pellet I tested was the American-made Vogel Match pellet with a 4.50mm head. These pellets compete at the World Cup and Olympic level. But the 126 doesn’t like them. It put 5 in a 10-meter group that measured 0.30-inches between centers.

Vogel group
Five Vogel pellets made a 0.30-inch group at 10 meters.


I have enjoyed testing the Gamo 126 Match rifle. I learned its strengths (the trigger and the light cocking effort) and its weakness (the complex and fiddly powerplant). I have wondered about it for years and now I know.

The accuracy is roughly on par with a Daisy 853 or 753 target rifle, though with much easier pumping effort and a far better trigger. Think of it as equal to the recoiling target rifles of its era, but subordinate to the recoilless ones.

Fit and finish are not up the the standard of the day, but they are adequate for the price that was charged. It’s the everyman target rifle. Think of it as Spain’s answer to the IZH MP532 target rifle — though nowhere near as accurate.


This is a report I have wanted to do for a long, long time. Now I know and never again need to doubt what this rifle is and what it can do. Does it belong in a collection of 10-meter rifles? Well, it’s certainly not a serious contender and never has been. But neither are the IZH 532, The Haenel 312 or the Daisy 853. I suppose to be complete a collection does need one of these.

Air Arms Pro-Sport: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Air Arms Pro-Sport.

Part 1
Part 2
Part 3
Part 4

This report covers:

  • The inspiration
  • The kit
  • Installing this kit
  • Disassembly
  • Examine the parts
  • Factory top hat
  • Install the PG3 mainspring/li>
  • Spring guides very tight!
  • Assemble the piston and spring
  • Compression chamber is buttoned
  • Finished assembly
  • Discussion
  • Cocking effort
  • Firing behavior
  • Velocity with Hobbys
  • Additional benefit
  • Velocity with H&N Baracuda
  • Summary

Today is the day, airgunners. This is the day we open the .22-caliber Air Arms Pro-Sport we are testing and install a Vortek PG3 tune kit. It’s a drop in one-for-one replacement powerplant kit that promises to lower the cocking effort of the rifle and smooth out the shot cycle. The power output is 12 foot-pounds in .22 caliber which would be a 11.9-grain RWS Hobby leaving the muzzle at 674 f.p.s. And someone says, “Gee, BB, don’t you know you’re not supposed to tune for LESS velocity?”

Yes, I do. And this is exactly what I want. Even if I only get 625 f.p.s. with the Hobbys it’s what I want. Because I’m going for smooth — not power.

The inspiration

The initial inspiration was a Venom Mach II rifle that was owned by Trooper Walsh. That was the rifle that the Pro-Sport was built to copy, and it was a sheer delight to cock and fire. However, at $2,000 in the 1990s, it was an airgun I could never afford to own.

Then a few months ago I happened to shoot Jeff Cloud’s Pro-Sport. Once again it was a sheer delight to cock and shoot. It reminded me of the Mach II of my past. Only this rifle is still being produced, and at a far more affordable price. And Vortek makes the spring kit that tames the beast,

The kit

The kit consists of a new mainspring, a spring guide, a “top hat” that is a forward spring guide living inside the piston, two spacer washers, a small tub of grease and instructions.

Pro-Sport PG3 kit
The PG3 kit consists of a new mainspring, a white spring guide, a black “top hat” forward spring guide for inside the piston, two washers that can be used as spacers to increase the preload of the mainspring , a small (but way more than adequate) tub of grease and the instructions.

The instructions tell how to install the kit. There are several options that can be applied, and the instructions address them. They do not tell you how to disassemble the rifle.

Installing this kit

I found this kit very easy to install, but before you jump in with both feet, remember that I have been doing things like this for decades. What seems easy to me may not seem that easy to you. I do find Air Arms spring guns easier to work on than any other brand for several reasons. First, they are so well made that you seldom if ever encounter a problem from the manufacturer. Second, neither the TX200 Mark III nor the Pro-Sport require a mainspring compressor to safely open the powerplant.

I had never opened a Pro-Sport before this day, so what you are about to see was as new to me as it will be to many of you. But the Pro-Sport only differs from the TX200 in a few small ways that aren’t a hindrance, and I know TXs very well.


First remove the barreled action from the stock. This is straightforward, except that both of the triggerguard screws need to be removed and the triggerguard with them. Both screws are attached to the barreled action. The rear one attaches to the rear of the trigger unit.

To get the action out of the stock the underlever needs to be opened (not cocked — just pulled away from the barrel) to slip out of the cocking slot of the stock. Once the action is out you can open it by unscrewing one bolt. It’s the bolt that the front triggerguard screw attaches to. It has an 11mm head and comes right out, but here is a tip. If you want to find out how much preload the mainspring is under you can press the back of the end cap on the action against a padded place on your bench while unscrewing the bolt by hand (once it’s loose). The pressure you have to press the action down with to make this bolt loose enough to turn by hand is the amount of preload the spring is under. The factory mainspring took about 40 pounds of downward pressure to turn the bolt.

Pro-Sport bolt out
When the bolt is removed the trigger comes out. It’s pushed by the mainspring, and this is as far as it goes. This is why a compressor is not needed.

Slide the trigger out of the gun and then slide out the mainspring and spring guide, followed by the piston. Because the Pro-Sport has a sliding compression chamber, the piston is not held in the gun at this point. If it doesn’t slide right out it may help to pull the underlever down smartly and the piston should come sliding out.

Pro-Sport mainspring and piston
The trigger slides out and so does the mainspring and piston.

Examine the parts

I looked at the parts at this point. I expected to see perfectly machined and finished parts because this is an Air Arms airgun. I was not disappointed. The spring was lubricated with their grease in what looked like the correct amount. Their grease is thinner than the Tune-In-A-Tube I plan to use, so a lot of vibration should disappear when I install and lube the new spring.

Pro-Sport mainspring lube
Air Arms lubed the mainspring perfectly. But their grease is thinner than TIAT.

Factory top hat

A top hat is a forward spring guide that lives inside the piston. It is engineered to take up all the slack in the inner diameter of the mainspring, so it doesn’t vibrate on the piston rod when the gun shoots. It can also add significant weight to the piston, which makes the gun more efficient with heavier pellets. I could see a top hat inside the piston by shining a bright flashlight inside.

The Vortek kit comes with its own top hat, so the factory part must be removed. It didn’t just slide out, so I used a 4 by 4 wooden post and whacked the rod end of the piston down on the post to jar it loose. One rap was all it took.

Pro-Sport top hat
One whack of the end of the rod against a post was all it took to get the top hat (left) out of the piston.

Install the PG3 mainspring

The PG3 mainspring has a short black Delrin top hat (forward spring guide) on one end. That goes into the piston. But that part has three notches on its rim for the end of the mainspring to rest in. These three are at different heights, so each puts a different amount of preload on the mainspring. I selected the lowest notch to put the least amount of preload on the spring.

Pro-Sport spring in top hat
See the end of the spring in the rounded notch? That determines the preload on the mainspring. This is the lightest setting.

Spring guides very tight!

I must comment here that both spring guides are very tight on the spring. The black one that’s inside the coils needed padded pliers to turn it so the end of the spring could go into the right notch. The white rear guide goes around the outside of the spring and is also tight. There was just a bit of Vortek lubricant on that end of the spring. I removed it because I am lubing with TIAT.

Tight spring guides are an airgun tuner’s trick for removing vibration. They are more difficult to control in manufacture because coiled steel springs don’t like to hold tight tolerances, and in this case both the OD and ID of the spring have to be precise. So, I have a lot of respect for the PG3 kit!

Assemble the piston and spring

Now I tried to slide the piston and new spring back into the gun. It should slip right in, but for some reason it stopped at the entrance to the sliding compression chamber. I fiddled with it for a minute and couldn’t get it to slide in, so I removed the sliding compression chamber to slide the piston into it outside the gun. Just one Allen screw connects it to the cocking linkage.

Pro-Sport Allen screw
Just one Allen screw (arrow) holds the sliding compression chamber inside the rifle. Remove it and the chamber slides right out.

Compression chamber is buttoned

I was surprised to see three button bushings at the front of the compression chamber. They keep the front of the chamber centered in the spring tube and offer little resistance to the chamber sliding when the rifle is cocked.

Pro-Sport chamber
The Pro-Sport sliding chamber (bottom) has three button bearings around its circumference to center the chamber in the spring tube. The smaller hole on the right is for the Allen screw.

Finished assembly

Once the chamber was out of the gun I was able to insert the piston into it and then slide everything back into the gun. The new mainspring is shorter than the factory spring, so there was even less preload on the end cap when I inserted the bottom bolt.


It took me a total of 40 minutes to install this kit, start to finish. At least 15 of those minutes were spent taking pictures. I had to wipe my hands before handling the camera for each photo And, when I say start to finish I mean starting with an untuned rifle and finishing by shooting the rifle after the installation. You always test a spring gun by shooting it after the tune because sometimes the parts aren’t in correctly. Shooting is the only way to find out.

The rifle fired the first time and I knew I had hit the nail on the head. It now cocks with much less effort and fires very smoothly.

Cocking effort

The factory-tuned rifle cocked with 48 pounds of force. Not only is that a lot, the fulcrum of the underlever is located in a place that makes working the underlever particularly difficult.

After the PG3 kit was installed the cocking effort is reduced to just 35 pounds. It’s still not light, but it’s far easier to cock this Pro-Sport now than before.

Firing behavior

The Pro-Sport is now calm when it fires. The factory rifle buzzed a little, but that is all gone, as I knew it would be. The TIAT guaranteed the buzz would leave, and the tightness of the PG3 parts assured me that I could use the TIAT sparingly. This rifle is now a delight to shoot!

Velocity with Hobbys

And now for the big test. I chose the RWS Hobby to test the rifle. In factory trim the Pro-Sport launches Hobbys at 760 f.p.s., which is good for 15.27 foot-pounds at the muzzle. The spread was 13 f.p.s.

As the rifle is now tuned the Hobby averages 633 f.p.s. for an energy of 10.59 foot-pounds at the muzzle. The spread of the 10-shot test string went from 628 to 639 f.p.s, a difference of 11 f.p.s.

Additional benefit

Not only is the Pro-Sport now easier to cock, it sets the safety every time. Because the cocking effort is reduced, the lever pushes the piston far enough back to set the safety without fail. It even set when I conducted the cocking effort test on the scale.

Velocity with H&N Baracuda

On my velocity test with the factory spring the H&N Baracuda pellets with a 5.50mm head were the most powerful, when they should have been the least. All things being equal, a lighter pellet produces more muzzle energy than a heavier one in a spring gun — or at least that is how it used to be. But the factory top hat I removed from the piston was weighted, which made the piston’s weight greater, and I felt this gun was made to shoot heavier pellets.

Since I removed that heavy top hat and replaced it with a Delrin one that has very little weight, I guessed the Baracuda pellet would no longer be more powerful than the Hobby. To produce 12 foot-pounds this 21.14-grain pellet has to travel 506 f.p.s. I guessed it would average around 475 f.p.s., which is good for the same 10.59-foot pounds as the Hobby. But that was wrong, too. With the PG3 tune as I applied it Baracudas now average 437 f.p.s., which is good for 8.97 foot-pounds. The spread went from a low of 433 to a high of 443 f.p.s. with is 10 f.p.s.


This Vortek PG3 tune kit did exactly what I wanted. The Tune-In-A-Tube slowed things down below the 12 foot -pound spec, but I couldn’t care less. I finally have the sweet and mellow Pro-Sport I was after!

The next step will be to mount the Meopta MeoPro Optika6 3-18X56-scope and see what she can do. I have very high expectations! After that — who knows?

Gamo Swarm Fusion 10X Gen II air rifle: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Gamo Swarm Fusion
Gamo Swarm Fusion 10X Gen II rifle.

Part 1

This report covers:

  • Well!
  • Another breakbarrel repeater
  • Easy loading
  • High velocity
  • Gamo Platinum PBA
  • Cocking is easy
  • Trigger adjustment
  • Trigger pull
  • RWS Hobby
  • RWS Superdome
  • H&N Baracuda Magnums
  • Gamo Platinum PBA — again
  • Pellet feeding
  • Summary


When I started the report on the Gamo Swarm Fusion 10X Gen II I didn’t know I was kicking a Texas fire ant mound! Part 1 of this report lead to a report on the history of Gamo, and that brought the show to a screeching stop! I won’t get into all that transpired, but you can read the comments if you are interested.

Another breakbarrel repeater

I’m not going to defend or criticize anyone in this report. All I’m doing is testing another breakbarrel repeater for power, accuracy and overall quality as it pertains to airgunning. With that in mind, let’s start the show.

Easy loading

Reader Yogi mentioned that one advantage about breakbarrel repeaters is they make it easier for people to load the rifle. My brother-in-law, Bob, got an Umarex Synergis underlever repeater for exactly that reason. He is now shooting it with an airgun club and having fun with it. I can tell you this Swarm Fusion 10X magazine is very easy to load. You don’t even have to remove it from the rifle to load it, which means you can treat the rifle as a single-shot if you like. The pellet still has to be fed into the barrel from the magazine by the feed mechanism, but you can change pellets on every shot if you want to.

High velocity

Gamo has long been a proponent of high velocity, and the advertised speed for this .177 caliber rifle I’m testing is 1,300 f.p.s. No doubt that is with lead-free Gamo Platinum PBA pellets. I will test it, of course, but it also tells me the powerplant is set up to handle heavy pellets. So I will test with those, as well. But let’s address the elephant in the room first.

Gamo Platinum PBA

This pellet is advertised to weigh 5.1 grains. I weighed 3 and got a range from 4.9 to 5.0-grains. Let me show you the string and then I’ll discuss it.

3………1183 fastest
8………1114 slowest

The “average for this string is 1154 f.p.s. but you’ll notice that no pellet went that speed. What we have here is a bimodal distribution, with 4 pellets going between 1114 and 1147 f.p.s. and 6 pellets going between 1161 and 1183 f.p.s. Either the gun is so new that it’s still breaking in, which is absolutely possible, or this rifle doesn’t like this pellet. That also seems possible, but I’m going to do a second test after I’ve tested all the other pellets to see which it is.

The velocity spread was 69 f.p.s. At the average velocity this pellet (using 5 grains as the weight) generated 14.79 foot-pounds at the muzzle.

At this point I have to say the rifle does not reach 1300 f.p.s. Not that it’s important — that’s not a velocity I want to reach. But it doesn’t.

Cocking is easy

I mentioned in Part 1 that the SwarmFusion is easy to cock. And it is, but even better, you don’t have to slap the muzzle to break the barrel open. It opens easily.

When I tested the rifle on my scale I was surprised to see the effort rise to 35 pounds. I would have bet money it was 10 pounds less. However, right after reaching that peak, the effort rapidly dropped back to less than 20 pounds. Then it hit me what is happening. Gamo has designed the cocking effort to peak at the point where you have the most strength and drop where your strength becomes less. It’s a geometry thing. That long cocking stroke has been engineered to help the shooter. I have to tell you — it really works!

Trigger adjustment

The two-stage custom action trigger (CAT) trigger is adjustable — HOWEVER. I wanted to adjust stage two to have a shorter pull, and that adjustment is made with a tiny Phillips screw located behind the trigger blade. The slot through the trigger guard to get on that screw straight is too narrow for any of my Phillips screwdrivers that have heads small enough to work. It measures 5.14mm wide.

My drone screwdriver fits the screw head that I’m guessing to be zero-size, but the blade is too short to reach through the slot, and the handle is too wide (6.85mm) to pass through the narrow slot. There is a larger hole behind the narrow one, but it’s for removing the action from the stock. Attempting to use it with the Phillips screwdriver makes the angle of the screwdriver too far off what it needs to be for the driver head to bite into the screw head. Since Phillips screws are so easy to bugger I won’t adjust the trigger today, but I did order a set of precision long shank screwdrivers that should allow me to adjust it the next time I test the rifle. Shame on Gamo for not including a tool for this adjustment — or for not selecting a fastener that wouldn’t have this problem!

Gamo Swarm Fusion trigger
The slot the second-stage trigger adjustment screw has to pass through is too narrow for any of my Phillips screwdrivers. Going through the larger hole behind that hole puts the screwdriver tip at a bad angle.

Trigger pull

Like the evening political news, however, all my complaining is meaningless because the CAT trigger pull is just delightful. Stage two has a long smooth travel. Just pretend it’s a single-stage trigger and you’ll be fine. The trigger broke at 2 lbs. 10 oz.

RWS Hobby

With lead-free lightweights out of the way, time to test the Swarm Fusion with a real lead pellet. Next up was the RWS Hobby — the lightweight pellet standard of the world. First the string. Don’t get used to this. I’m only showing it today because I need to talk about it.

1………971 fastest
5………949 slowest

The average for this string is 960 f.p.s. and, as you can see, this string is a LOT tighter than the first one. The extreme velocity spread here is just 22 f.p.s. At the average velocity this pellet generated 14.33 foot-pounds at the muzzle.

RWS Superdome

Now let’s bump the pellet weight up a bit and shoot the 8.3-grain RWS Superdome. First the string.

4………863 slowest
6………did not register
8………did not register
10……..881 fastest

The average for the 10 shots that registered was 872 f.p.s. At that speed Superdomes generate 14.02 foot-pounds at the muzzle. The extreme spread for them was 18 f.p.s. The rifle may be breaking in, but as the pellets get heavier the velocity spread goes down.

I actually shot 12 pellets because of the two that didn’t register. Loading the extra two pellets was so simple, thanks to that magazine.

H&N Baracuda Magnums

The last pellet I will test is the super-heavyweight H&N Baracuda Magnum. The box says they should weigh 16.36-grains, but the four I weighed varied between 15.4 and 15.8-grains. That’s a pretty big difference — both in the spread of pellet weights and also from the weight that’s listed on the tin! Three of the four weighed 15.8-grains.

Because this pellet is so heavy it is also very long. This gave me an opportunity to see if they would both fit into and cycle through the circular magazine. And, they did! Not a bit of trouble! Here is the string.

7………492 slowest
9………515 fastest

The Baracuda Magnum generated 8.77 foot-pounds at the muzzle, based on a weight of 15.8-grains that most of them weighed. The velocity spread was 23 f.p.s. I don’t think this is a good pellet for this rifle.

Gamo Platinum PBA — again

Now I wanted to test Gamo Platinum PBA pellets again. Remember they gave a bimodal distribution in the first test. First let’s look at the string.

4………1124 slowest

The average for this string is 1153 f.p.s. — only 1 f.p.s. slower than the first string. The spread was 57 f.p.s. That’s better than the 69 f.p.s spread on the first string, but still way more than any of the other pellets. There is less of a bimodal distribution this time, but I now believe that it is the pellet and not the break-in that’s responsible for what we see.

Pellet feeding

The magazine functioned throughout the test without a slip-up. Fifty-two pellets fed smoothly through the gun. Have no concern there.


This test turned out differently than I expected. I expected the rifle to get over 1,300 f.p.s., because when Gamo says that they usually do. However I do like the trigger, and the rifle cocks easily despite the weight that I saw. The rifle is lightweight yet doesn’t  slap you when it fires, like many gas spring guns do. And the pellet feeding was flawless. I sure hope this rifle is accurate, because if it is, it’s a winner!

Daisy 22SG multi-pump pneumatic: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Daisy 22SG
Daisy 22SG.

Part 1
Part 2

A history of airguns

This report covers:

  • The test
  • Check sight-in
  • RWS Hobbys
  • Beeman Kodiaks
  • RWS Superpoint
  • JSB Exact RS
  • RWS Superdome
  • JSB Hades
  • Discussion
  • Summary

Today we learn how accurate the Daisy 22SG is. The rifle was already scoped so I hoped it would be close to zero, if not spot-on. I didn’t know what pellet(s) shot well in the rifle, so this test starts from the beginning.

The test

I shot the rifle off a sandbag rest at 10 meters. I shot 5 shots per group and pumped the rifle 6 times for each shot. In the velocity test we learned that 6 pumps pushes an RWS Hobby pellet out at around 500 f.p.s. That’s fast enough for punching paper.

Check sight-in

Since the rifle is scoped I first checked the zero from 12 feet before shooting from 10 meters. The pellet hit about an inch below the aim point and a little to the right. It was hand-held, but that was close enough to start shooting from 10 meters. I expected the pellet to rise at that distance and it did. It’s hard to say how much it rose because 5 Hobbys went into 0.925-inches at 10 meters, but the center of that group seems to have risen about 3/4-inches. I am not showing that group.

RWS Hobbys

I adjusted the scope up several clicks and shot a second group. This time 5 Hobbys went into 0.659-inches at 10 meters. The group looks larger than that because the top pellet tore the target paper a bit, but I can see where the pellet impacted and I measured from there.

Hobby group
Five RWS Hobby pellets went into 0.659-inches at 10 meters. The group appears larger because the top pellet tore a piece of target paper that extends to the right.

Beeman Kodiaks

Someone may have commented that their 22X or SG shoots well with Baracudas. I tried some Beeman Kodiaks next, which are the same pellets as Baracudas. Five of them went into 0.691-inches at 10 meters. The group is horizontal, but I didn’t notice that while testing. I’m not sure I could have done anything about it, either.

The Daisy 22SG put 5 Beeman Kodiaks into 0.691-inches at 10 meters.

After this group I adjusted the scope up and to the left. There seems to be no stiction in this scope because the first shot after adjustment went right were it should.

RWS Superpoint

The next pellet I tried was an old standby — the RWS Superpoint. They are often quite accurate in vintage airguns. The 22SG put five of them in 0.661-inches at 10 meters. And that is an interesting measurement, because the first two groups measured 0.659- and 0.691-inches. At this point in the test it started to look like that was about the group size I would get regardless of the pellet that was shot.

Superpoint group
Five RWS Superpoint pellets went into 0.661-inches at 10 meters.

JSB Exact RS

Well, the next pellet — the JSB Exact RS — blew that theory right out of the water! Five of them went into 1.131-inches at 10 meters

JSB RS group
Five JSB Exact RS pellets made this 1.131-inch group at 10 meters.

RWS Superdome

Next to be tested were five RWS Superdomes. Five of them went into 0.783-inches at 10 meters. Okay, we are back to the good range again!

Superdome group
Five RWS Superdomes made this 0.783-inch group at 10 meters.

JSB Hades

The last pellet I tested was the JSB Hades hollowpoint. They do very well in many airguns, so I thought, “Why not?” Except for the unusual “hollowpoint,” this pellet is a domed diabolo. And, like the JSB RS pellets, five of them went into 0.96-inches at 10 meters. This was the second largest group of the test, with the JSB RS being the largest.

Hades hollowpoint
Five JSB Hades hollowpoints went into 0.96-inches at 10 meters.


The Daisy 22SG is not a tackdriver, that’s for sure. But it puts pellets where they are aimed for the most part. It’s certainly a good little plinking airgun.

There may be one or more pellets that deliver stunning accuracy that I just haven’t found, but what we see from my little test is the rifle will put five pellets it likes into less than 3/4-inches at 10 meters.

The rifle might have tightened up a little with more pumps, but I pumped it 240 times just for today’s results! That’s enough!


I learned a lot in this test. I resealed the pump in five minutes on the fly, which is the fastest any airgun has ever been fixed by me.

The trigger is heavy, but the pump effort is light. This is an air rifle you can shoot a lot, as long as you aren’t in a hurry.

The scope’s parallax isn’t adjusted for 10 meters, but it works. I don’t think I’ve ever shot this rifle with the open sights.

There are a lot of recent “vintage” airguns, if you just take the time to research them. This has been a detailed look at one of them that is admired by more than just airgunners.

Crosman 760 Pumpmaster Classic: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Crosman 760 Pumpmaster Classic
The new Crosman 760 Pumpmaster Classic.

Part 1

This report covers:

  • BB feeding
  • Loading pellets
  • Velocity
  • RWS Hobby
  • Velocity-per-number-of-pumps
  • Discussion
  • Sig Match Ballistic Alloy
  • Sig velocity-per-number-of-pumps
  • Crosman Premier Heavy
  • Premier velocity-per-number-of-pumps
  • Pump tube very warm!
  • Hobby pellets on 10 pumps second time
  • Hobbys on 10-pumps — again!
  • Crosman Black Widow BBs on 10 pumps
  • Trigger pull
  • Pump effort
  • Clacking pump handle
  • Summary

Okay — you are either for or against this airgun. There doesn’t seem to be much of a middle ground. I won’t take sides, but I am aware of all of your feelings.

BB feeding

First up is the “special” BB feeding method that I found quite by accident. I was reading the comments on the Pyramyd Air website and saw one or two complaints that the BBs don’t feed well in the new gun. With the older 760 I know they feed from the top inside of the receiver and you have to pull back the spring-loaded feed button on top of the receiver to get the BBs to fill that small magazine from the larger reservoir inside the receiver. My older 760 is a first model that holds 180 BBs. This new gun holds 1,000.

Once the BBs are inside the small inline magazine on top of the receiver they roll forward and drop one-by-one into the place where the bolt tip will catch them. When the bolt comes back they drop and attach to the magnet on the end of the bolt as if by magic. However, in my old gun they only feed correctly a fraction of the time. The new 760 Classic is different, in that the small BB magazine that feeds to the bolt is very visible. I showed it in Part 1. And I learned something that helps this new gun feed right every single time.

The BBs in the visible magazine on top, both old and new, roll forward when the muzzle is depressed. So when loading a BB (that’s cocking the bolt ALL the way back and easing it forward) you should see a BB on the tip of the bolt. The old gun has a brass bolt that has to depress a spring-loaded catch in order to rotate into its storage slot in the receiver after loading. The new gun’s bolt moves straight forward until the bolt handle pops up just a little as it closes at the very end of the stroke. With both guns hold the muzzle below level while doing this. That’s it!

Loading my old 760 is like playing with a magician’s trick box. I still haven’t learned the secret. Sometimes it works and other times I saw the lady in half! The new gun feeds BBs flawlessly.

Loading pellets

Pellets are a different story and no problem to load with either the new or the older gun, though the new gun has sloped sides to the breech trough while the older one has sides that are flat. The older gun has a screw hole in the center of the breech trough that is designed to turn half of your pellets around backwards as you insert them into the breech. The new gun has a smooth loading trough that works better, though it did flip around a significant percentage of pellets.


Now let’s look at velocity. We have both pellets and BBs to test, so let’s get right to it. The Crosman box says the new gun gets up to 700 f.p.s. with pellets on 10 pumps, but Pyramyd Air lists it at a more conservative 600 f.p.s. with pellets. Why don’t we try that first?

Crosman 760 box
The box clearly says pellets go up to 700 f.p.s. on 10 pumps.

RWS Hobby

I’ll start with the RWS Hobby pellets pellet, since it is the velocity standard for lead pellets. On 10 pumps Hobbys averaged 578 f.p.s. However, something interesting happened as I shot the string. Let’s look.


Up to shot number 5 things were very stable. But with shot 6 the velocity started increasing. I think we all know what’s happening. The pump cup or o-ring seal is warming up and sealing the compression tube better.

At the average velocity this pellet generates 5.19 foot-pounds of energy on 10 pumps. Since this is a pneumatic we expect heavier pellets to generate more energy and light ones to generate less.

I will come back to this with more interesting observances, but now I will do a different test — the velocity-per-number-of-pumps test.




Okay, let’s talk. When I saw the velocity rising in the first string I figured the average velocity was really closer to the fastest velocity recorded than to the number I got. I will come back and test that in a bit.

Also, do you see how consistent this airgun is? I don’t think I need to shoot any more 10-pump strings. I will just shoot the number-of-pumps-per-shot tests on the rest of the pellets.

Sig Match Ballistic Alloy

If we are going for velocity we will get it with a lightweight pellet and the all-tin Sig Match Ballistic Alloy pellet is a perfect one to test.

Sig velocity-per-number-of-pumps

Okay, I think we can take 655 as a conservative velocity average for this pellet on 10 pumps — see where I’m going with this? At that velocity this 5.25-grain tin pellet generates exactly 5 foot-pounds of energy at the muzzle. A lighter pellet has produced less muzzle energy — just as the theory suggests.

Crosman Premier Heavy

For a heavy pellet I chose the Crosman Premier Heavy. At 10.5-grains it fits the bill, plus it is a dome, and I wanted to test a dome in this airgun, too. Here we go.

Premier velocity-per-number-of-pumps


If I take 456 as the average for 10 pumps (being conservative again), this heavyweight pellet generates 4.85 foot-pounds at the muzzle. Oh, oh. The theory failed! What happened? I don’t think it was the theory that failed as much as something else. Can you guess what it is? I’m about to reveal something that I think you will find interesting. So — why did heavier Premiers generate lower energy than Hobbys?

Pump tube very warm!

Before I show you what I think led to this result, let me shoot another string of Hobbys on 10 pumps per shot. And before I do that — remember what I said about the pump seals warming as I pumped? Well I felt the outside of the pump tube and at this point it was very warm. The seals are also definitely warm. Let’s shoot that string.

Hobby pellets on 10 pumps second time


Now we have something to discuss! And THIS is a classic example of why a chronograph is so important! I told you earlier that I expected the average for Hobbys on 10 pumps to be close to the fastest velocity recorded. That would be around 600 f.p.s. Look what happened instead. On shot number 8 the velocity dropped below 580. What’s happening?

The answer to this question is the same one that I asked you just a little bit ago. Only at that time I asked why the heaviest pellet was not also the most powerful, as the theory predicts. I think the answer is oil — as in not enough of. I mean the pump seals are getting dry and that is shaving velocity off the top. So I will run another test.

Hobbys on 10-pumps — again!

This time I oiled the pump piston seal with Crosman Pellgunoil — (Crosman gun, so why not use their oil?). Then I shot 5 shots across the chronograph for record. Here they are.


I didn’t bother calculating the average because the velocity was slipping so fast.

See what oil does? That is a dramatic result! But I knew the pump seals were warm, so I set the gun aside for two hours and then shot 5 more shots. This time the pump was cool and the oil had been spread around.


This time I did calculate the average, which is 587 f.p.s. for these 5 shots. I think we can surmise that the average velocity with Hobby pellets on 10 pumps will be something above 580 f.p.s. but below 600 f.p.s. I could go on and do other interesting things, but how about a string of BBs? Since this is a Crosman airgun I will choose their BBs, but not the Copperheads that have always been on the slightly small side. I will use the new Crosman Black Widow BBs instead. The PA website says the gun gets up to 625 f.p.s. with BBs, while the box says 645 f.p.s. Remember I mentioned this in Part 1 and asked you why the pellets that are heavier went faster than the BBs? I think I now know the answer. Someone at Crosman overlooked this when proofing the artwork for the box, or something in the gun changed after that time and the box got out claiming 700 f.p.s. with pellets and 645 with BBs.

Crosman Black Widow BBs on 10 pumps

Black Widow BBs on 10 pumps

The average for this string is 610 f.p.s. And, as you can see, BBs do go out of this gun as fast as 637 f.p.s. These Black Widows weigh 5.23 grains apiece, so the average muzzle energy calculates to 4.32 foot-pounds.

Trigger pull

The single-stage trigger pull is 6 lbs. 1 oz. I do note that the trigger became noticeably smoother in just the 65+ shots of this test. I think it will break in to be very smooth.

Pump effort

This gun is made for children, so the effort needed to pump is important.

Pumps……Effort lbs.

You have to decide what these results mean. Some kids won’t be able to pump the gun and others will. I will tell you that by pumping slow the effort stays as low as possible. You might loose a few f.p.s., but it shouldn’t be that bad.

Clacking pump handle

When the plastic pump handle smacks against the plastic frame of the gun there is loud clack. It’s louder than a loud hand clap and if you are pumping many strokes it does get distracting.


So far I find a lot to like about this new Crosman 760 Classic. At $35 it could very well be a best buy — as long as your accuracy expectations are realistic. We shall see.