TX200 Mark III: Part 9
by Tom Gaylord, a.k.a. B.B. Pelletier
This report is getting long and perhaps a little confusing, so let me explain what I’m doing. We’ve been looking at the Air Arms TX200 Mark III underlever air rifle. I used my own TX for the first 6 parts of the report. In Part 7, I introduced a brand new TX that Pyramyd Air sent for me to test. Many of you were concerned that the rifle had changed somehow over the years since mine was made, and perhaps what’s shipped today isn’t the same rifle…so I agreed to test a new one for you. The first look at that rifle came in Part 7 of the report, and in Part 8 we looked at the velocity.
Today ,I’m going to show you the trigger in detail, describe how to adjust it and explain why I always say the TX trigger is an upgrade of the Rekord trigger that Weihrauch introduced back in the 1950s. To get to the trigger adjustments, the triggerguard must be removed. But today I’m going farther into the gun to show you the entire trigger assembly. That will help me explain how the trigger functions.
The stock needs to come off to get into the rifle, so I did that first. Just remove 2 forearm screws and 2 more triggerguard screws.
Once out of the stock, the action and trigger can be seen clearly.
Here you see the disassembly bolt (all the way to the lef). Turn it out, and the rifle comes apart. You can also see the 3 trigger adjustment screws. On the trigger blade are screws to adjust the first-stage length and adjust the sear contact area. Behind the trigger blade is an Allen screw that adjusts the trigger pull weight. Behind that is the threaded hole the rear triggerguard screw goes into.
If I were just adjusting the trigger I wouldn’t need to go even this far. Just remove the triggerguard and start by adjusting the trigger return spring tension. I found that was all I needed to do on the test rifle, as the first-stage length and sear contact area were right as they came from the factory. But you can adjust either of them or both.
To take the trigger unit out of the gun, I removed the disassembly bolt. As it turned, I pressed down on the entire barrelled action with the end cap resting on a soft cloth pad. When the bolt was free, the mainspring decompressed less than 2 inches.
When the trigger unit comes out of the rifle, it’s still pinned to the end cap and spring guide like this. Now, the trigger unit looks familiar to Rekord owners because the 2 pins that hold it to the end cap are visible.
Because I want to show you how this trigger works, I’m going to continue to disassemble the end cap. The 2 pins that hold the trigger unit in the cap are driven out. They are several times harder to remove than Weihrauch trigger pins. This unit is together very tight!
Once the trigger assembly is out, we can see how it differs from the Rekord.
The trigger assembly is similar to the Rekord — but also different. The box is riveted together instead of being a folded sheet metal structure. There’s an additional pin, forward of the trigger blade, and internally there are bearings where the Rekord parts just turn on pins.
So far, I’ve shown you the differences but not described how they work. For starters, the Air Arms trigger has adjustments for the first-stage pull and for the sear contact area, as well as for trigger-pull weight. The Rekord has the sear engagement adjustment and the pull weight adjustment but not the first-stage adjustment. But that isn’t what makes the Air Arms trigger better.
What makes the Air Arms trigger better is the presence of bearings instead of just pins. The parts are also more finely fitted, which has to be done during manufacture because there’s no money in the gun for costly hand-fitting. And the trigger isn’t the only place that’s different. The piston is also different.
The TX200 has what I will call a circular piston. All pistons are circular, of course, but most of them are held from rotating by the cocking shoe. Because of that, the piston can have a hook that’s engaged by the trigger when the gun’s cocked. That’s how the Weihrauch rifles that use the Rekord trigger are made. But what if the piston was free to rotate on its axis?
Blog reader RidgeRunner asked how the TX piston was cocked by the sliding compression chamber. The answer is that the chamber pushes the piston back until the trigger catches it. The piston rod is so long that it can be caught by the trigger while the piston is still inside the compression chamber.
When the gun is cocked, the piston rod comes back and pushes the trigger parts into lockup. As they lock up, a hook catches the rear of the piston rod and holds it until the sear releases it.
The ability of the piston to turn on its long axis while being supported front and rear by bearings adds smoothness to the powerplant without sacrificing power. A centrally located air transfer port that’s centered on the piston boosts the air scavenging efficiency and therefore the available power. The TX200 Mark III is giving all the power it can from a powerplant that’s still smooth and easily cocked.
How is the trigger after adjustment?
Before I adjusted the trigger, it released crisply at 1 lb., 12 oz., which is 28 oz. All I adjusted was the trigger return spring tension and now the trigger breaks cleanly at 12 ounces. So the adjustment dropped one entire pound. And, yet, the sear still has the same contact area, so it’s just as safe as before.
A good tuner can adjust a Rekord just as light, but the sear contact area won’t be as great as it is at 3 lbs. The Air Arms trigger allows for this adjustment without sacrificing any safety. That’s what I meant by the TX trigger being more finely adjustable that a Rekord.
By the way, the work done here, including taking the pictures, took a total of 30 minutes.