FWB 127. It’s the same rifle as the 124 only in .22 caliber.
This report covers:
- The mainspring
- Power down?
- Trigger assembly and spring guide
- Rifle has been tuned
- More proof of tuningPiston seal
Today we disassemble the FWB 127 to find out what parts are needed for a rebuild. Obviously from the last test in Part 2 the rifle is not performing as it should.
Step one is to pop the barreled action out of the stock. And just to keep that easy I also removed both front and rear sights.
The 127 barreled action is identical to the 124 barreled action.
The FWB 124/127 is on the easier side of spring-piston airguns when it comes to disassembly and assembly. I did use a mainspring compressor but no other special tools.
The powerplant is held together by one bolt that is also threaded for the front triggerguard screw. Put the barreled action in the mainspring compressor and take a slight bit of tension off the end cap. Then the bolt almost unscrews itself.
The bolt that holds the 127 together. Only remove it when the rifle is in a mainspring compressor.
Once that bolt is out back off on the mainspring compressor and the end cap assembly that contains the trigger assembly, the safety and the rear spring guide slides out of the rifle.
Here you see the end cap with the trigger assembly. The wings on the right are the safety.
Once that bolt is out the end cap assembly and the mainspring slide out of the spring tube.
When the mainspring came out I saw that it was coated with black tar grease. That costs about 30-40 f.p.s. in velocity. I will recover that without losing velocity by using Tune in a Tube (TIAT) grease when I assemble the rifle again.
The black tar grease is all over everything. It will have to be cleaned off before the rifle is assembled again.
I held off ordering parts for the 127 until I saw the condition of the parts that are in the rifle now. The mainspring was a surprise because it isn’t an FWB factory spring. It’s an aftermarket spring with many less coils than the factory spring — six or seven less coils for sure. I know by counting the coils on this spring and comparing them to a replacement factory spring from a 124 tuneup report. I counted those in the photo of the same report.
The mainspring that was in the rifle looks fine. In this image the coils in the center look slightly collapsed in this photo but I examined the actual spring and can tell you that this is an optical illusion.
I cleaned all the grease off the spring and then rolled it on a flat surface. There are no kinks in the coils and only a very slight wobble in the roll that some factory springs might also have. In other words, it’s in very good condition. I could put it back in the rifle and, with the elimination of the black tar grease, pick up 30-40 f.p.s. And perhaps the same or a little more with a new breech seal. But that still leaves the rifle in the basement. Right now it’s a 9 foot-pound rifle that should be a 15-16 foot-pound rifle. A fresh breech seal and TIAT might bring it up to 12-13 foot-pounds but that’s it. I’m not a power monger, but I want more than that from this rifle.
The mainspring is the principal reason this rifle’s power was down. The man I got this rifle from thought the piston seal needed to be resized — that it was too tight for the compression chamber. But that spring is the main reason for the low velocity, with the breech seal and black tar grease minor and secondary reasons.
Trigger assembly and spring guide
Once free of the mainspring I wiped off the rear spring guide and trigger assembly. The FWB 124/127 trigger is pretty basic and doesn’t offer the same range of adjustability as a Rekord or Air Arms trigger. But when I owned the Queen Bee 124 I noted that its trigger was adjusted to near perfection. So I know it’s possible. I will first test this one during the accuracy test and then try to adjust it similarly.
The trigger assembly includes the rear spring guide. That white Delrin or Nylon bushing is not factory. It’s supposed to work with the shorter mainspring to bring back some power. You will note a similar bushing or top hat on the piston end of the spring that does the same thing.
Rifle has been tuned
At this point it is obvious this rifle has been tuned. And tuned by someone who knows their stuff. Except for the black tar, this tune was specific and ideal. And maybe TIAT wasn’t available at the time this work was done.
The flattened and hard breech seal I showed you in Part 2 is a clue that this work is no less than ten years and more likely 20 years old.
That breech seal is shot. There goes a lot of velocity! The bore could benefit from a deep cleaning, too.
More proof of tuning
Tuning a springer like the 127 also means deburring and smoothing the steel parts that are in contact. I tend to do less but others tend to do more. This rifle was tuned by one of the “more” guys.
The surfaces of this cocking slot have been deburred and smoothed. This is clear evidence of aftermarket tuning.
The guy who sold me the 127 thought the piston seal needed to be reduced in size, but when I slid the piston out of the spring tube it was clear that the piston seal is either just right or it borders on being slightly too small. It is certainly not too large. Let me show you what a proper seal fit looks like.
This is the piston seal I sized for the last FWB 124 I tuned. When it fits the spring tube like this, it’s sized correctly. If it was too large the seal would be distorted or folded at some place. After the seal sides are lubed with moly grease it slides smooth and tight in the tube.
The 127’s piston seal is sized correctly and also lubed as it should be.
Now that I knew the condition of all the parts, I was able to place an order for parts. Fortunately for me it was just a mainspring and a breech seal. I ordered them last Friday and they should be here in a week or so.
My plan is to clean out all the black tar grease and then install the new spring and breech seal. I’ll show that to you. I will lubricate everything with TIAT and moly grease and then we will test velocity again.
After that we’ll look at accuracy and, if necessary I’ll do something with the trigger, though really I don’t think it needs it.