by Tom Gaylord
Writing as B.B. Pelletier
Air Arms Pro-Sport.
This report covers:
- The inspiration
- The kit
- Installing this kit
- 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
- Cocking effort
- Firing behavior
- Velocity with Hobbys
- Additional benefit
- Velocity with H&N Baracuda
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 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 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.
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.
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.
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.
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.
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.