Derrick's Two-Tone FWB 124

I did the work on my Feinwerkbau before I started writing for the blog. As a result, I have no notes and don't have many of the images that I'd like to have for a blog post. Specifically, I don't have a single "before" picture. If you can simply imagine "beat to all heck" you've got the right idea. I've put off writing this post largely because of that, but the 124 is such a classic rifle, Nick and I thought we needed something tangible here.

Compete with backstory: My very first air rifle was purchased used from a gun shop back in the mid to late 1980's, a Feinwerkbau 124D. Years--and many other air rifles later--I sent the FWB off my good friend, Jerry, on long-term loan. At the time, I really didn't care whether or not the rifle ever came back. Then, a year and a half ago, I lost all my field rifles in a burglary. Weihrauchs and Air Arms: gone. When Jerry heard the news, he immediately said he was returning the FWB. Insisted, in fact. I'd practically forgotten about it as I hadn't seen it in at least 15 years. Anyway, I was traveling and it would be a couple weeks before we could make the connection. In the interim, and partly to console myself over the loss of the guns, I bid on--and won--a handmade walnut stock offered on GunBroker.com from S. Ionescue. Figured I'd dress up the old girl.

Then the rifle showed up.

The gun was cocked when I picked it up. Probably had been for a decade. The compression tube was missing about 30% of the blueing and rust had set in. Luckily, the barrel/breech block assembly cleaned up and looked OK. I was dejected at the thought of dropping this ugliness into a handmade stock. The cost for a re-blue was steep yet do-able, but would push the time frame back another month or more.

I test-fired the gun over the chrony and the pellet didn't even leave the breech. Absolutely no compression. The piston seal had disintegrated.

I disassembled the rifle (yep, no pics) and dug the remnants of the seal out of the compression tube. Wax like chunks. Note the moly on the seal. The gun had been tuned before it was given away. I've read about the FWB 124 seals deteriorating, but this was my first experience seeing one.

The mainspring had taken quite a set as well as some cant.

In my pile of airgun parts was a complete FWB 124 rebuild kit purchased from Beeman probably in about 1990. The spring on top is the one removed from the rifle. Lower is a new spring. Looks like the old spring is 1.5" shorter. Even with the FWB rebuild kit, I wasn't interested in installing a piston seal from at least 20 years ago that we now know will fail due to age. I ordered a Maccari spring and seal kit and waited.

With the gun in pieces, I tried to refinish and salvage the compression tube. Couldn't get a cold blue to look even halfway decent. Tried at least 3 brands. Finally gave up and thought about the 2-tone Beeman commemorative HW rifles from the early 90's. A call to a couple of my machinist friends got me the name of the best chroming shop in the area. Akron Plating is less than 10 blocks from my house.

I took the compression tube down and explained what it was and what it does and had it hard chromed. Not nickel chrome--that's for Harleys. More subdued, it's sort of a light gray satin finish.



They did a great job leaving the lettering clean and sharp.

Absolute relief when I picked it up. The chrome finish was flawless.

The Maccari Mongoose spring is on the bottom. Shorter than the FWB springs, yet it promises more power. I don't remember if I asked Maccari to set the spring before he shipped it to me. He offers to "set" springs for $1 each. It compresses the spring slightly and can make initial installation easier. It's most likely that I didn't ask, as I've got a brute of a spring compressor.

Touched up the safety and all the small pieces as needed with cold blue.

Looks like a lot going on, but it's a pretty straight forward gun to repair.

Spent a lot of time polishing everything. This is the cocking shoe.

Piston was especially smoothed at the rear where it can drag inside the tube.



Wanted to tighten the fit between the ID of the piston and the OD of the mainspring.

Cut and deburred a piece of sheetmetal.

Found a dowel that's about the same OD as the spring.

Formed the sheet around the dowel.

Worked slowly and carefully to avoid folding or wrinkling the sheet metal.

Trimmed to fit the slot for the cocking lever. This was a "try and see" approach.

Pretty much got it to shape.

Carefully pressed into place.

Installing the spring will finish seating the shim.



Today, most spring guns use a separate spring guide. On the 124, it was machined as the forward end of the trigger housing.

Another shot of the pison

The Maccari seal was a really tight press fit.

This is the power plant.

You can see how much longer it is than the compression tube. Remember that the fork tangs on the tube are almost 2" long and it gets even longer. A spring compressor is a must to fit all this into the tube under some modicum of control.

Flex-Honed the inside of the compression tube. The honing scratches the walls and creates a base for the moly grease to adhere.

Barrel, breech block, cocking lever assembly.

Top view. A FWB plate covers the screw holes from the open sight.

Assembled. I moly'd the compression chamber and the piston seal. The spring got a thin coat of Maccari Heavy Tar to damp any possible spring vibration.



The front sling swivel had to be removed to fit the action into the stock. Required tapping out the rivet for the cocking lever and bushing the sides with washers.

Stock arrived from Ionescue.

The pictures don't do it justice.

Schnaebeled forend.

The edge of the rollover cheek piece is sharp.

Actually, all the features are sharp and well-defined. Exceptional work.



Dropped the action into the stock. It was a very snug fit, but I don't recall doing any wood removal.

Found some stainless steel cap screws

Mounted a Leapers 3-9X40mm scope in a set of medium Accushot rings. I modified the rear scope ring to provide a ball-end scope stop to mate with the 124's cross-grooved receiver. It hasn't moved a bit. I should take the scope ring apart and do a separate blog as it's getting harder and harder to find suitable scope mounts for 124's.





Had a trigger shoe for a 124. The trigger on this rifle is the aluminum blade. I refinished it with Birchwood Casey Aluminum Black.

An old model RWS barrel weight/stabilizer finished off the muzzle. The gun is currently shooting RWS Hobby pellets in the low 860's. Apologies for the rather dis-jointed nature of this post. Wish I had pics of the gun before I started as well as shots of the disassembly procedure. I'm kicking around buying a Maccari trigger. If I order one, I may revisit a complete tear-down, but right now, the rifle is shooting better than new and it's hard to get excited about messing with that.

Haenel 310 Rear Sight Elevator

Now to get the rear sight working...

Here's my initial drawing...my only change was to go with a smaller radius on the top.

I punched out the pin.

I did not lose the spring.

I milled a channel in a 14"x1/4"x1/2" piece of plastic. I'm not sure what type of plastic it is, probably UHMW. It is very slippery. So I had to take lots of light cuts.

I rummaged around in my tooling and found this tiny woodruff keyseat cutter, which worked fine for making the undercut slot.

Fits perfectly!

Then I milled some ears on the underside.

And used a 90 deg. vee cutter to make them into wedges. These mate with the vee cuts in the sight.

A small radius relief...

I was going to cut the serrations on the mill but decided it would be safer (slippery plastic...) to use a checkering file.

Not perfect but it looks fine.

Installed and works fine.

Here are some of the tiny cutters I have...

Some Notes on Reassembly of the Haenel 310

Reassembly of the Haenel 310 was pretty straightforward.

I gave the leather seal a trim as the leather had mushed a bit. Later I also scraped the sides with a razor blade to remove some of the thick dirty grease....

It's important to line up the screw hole with the piston. See how grey the piston seal is? I scraped that off...

When the piston is slipped in I had to stick a thin screwdriver between the piston and the bushing so I could then lever the bushing into place.

Then as I showed I used a rod (in this pic the handle of a pin punch) to put the bushing in position.

And captured it with a pin punch.

The end cap mates with the tangs on the trigger block.

The end of the safety mates and locks over that bent tab inside the trigger group. So the safety is rotated 90 degrees and pushed over and then rotated back...

The shot I have varies in size...

That's the same piece of shot as above, out of round by .11mm (.004")
I need some truly round shot.

In any case after the first reassembly velocity had crept up to 280 fps from 250. Not great. So I tore it down again and as I said above, shaved the sides of the piston seal, nothing extreme but I wanted to get down to clean leather from the grey mess of the piston. I had a feeling that the greasy dirt was robbing velocity. For once I was right. It is now doing between 300 and 320 fps. I have the feeling, as Tom Gaylord said, that oiling the seal often helps a lot. I'll keep an eye on the velocity over time.

I also think that the out of round shot robs some velocity due to pressure loss around the edge of the shot. I pushed one through the barrel and there were only two spots where the rifling engaged the shot. Anyone have some German Punktkugeln in 4.4mm they want to send me?

Now I need to make a new sight elevator...

Haenel 310 Disassembly, Part 2

On I go...

The first time I disassembled the rifle (yes, I've done it more than once in the past few days...) I punched the pin out, removed the pin punch and something went "sproing-klunk" inside. I try and avoid that.

I found that it's easiest to have the action like this, held in a vise.

The pin is punched out.

A stout rod or pin punch takes up the spring force by hand and the pin punch is withdrawn from the cross pin hole.

Then the spring is relaxed...the spring force is not great.

The pin is grooved?

I pulled out the spring and piston assembly.

It's always something new with airguns.

The tube feeds the shot from the magazine and acts as one long transfer port for the compressed air (see the slot just in front of the piston seal?)

That tab at the end with the sides cut off would have to be navigated around in order to use a spring compressor. Notice the large sear surface.

Another view.

The nasty, greasy,leather seal. That small setscrew locks the piston head in place.

So I removed it.

The piston face unscrews with a spanner...

So I made one out of some steel pipe.

I milled away to make a spanner.

Unscrewing the piston face.

All the piston parts. Now it's just cleaning, reassembly, testing, disassembly, tweaking, reassembly...to come later...

Haenel 310 Disassembly, Part 1

I recently bought a Haenel 310-2 and Haenel 311 from a gentleman who answered one of my "WTB Beaters" posts on the yellow forum. The 310 had low power and is missing the front sight hood and rear sight elevator. There's some good info about the 310 up on Tom Gaylord's blog (part 1&2, part 3&4), as well as this Russian forum post, And muzzle.de although it's about the 310-4...
The 310 shoots 4.4mm round ball. I'll talk more about that later but I wonder if anyone knows of a source for precision round lead balls in 4.4mm (called "punktkugeln") from Germany? I found a few websites but am hesitant to order online in a foreign language...JG Airguns does have shot but I fear it's the same shot as the other US sourced shot I have which is not round (if it is truly round, let me know!). JG Airguns also has used Haenel 310s for $99.99 which is a pretty good deal if they're in ok shape.

The 310-2 held by my hard working imp.

The front sight is missing the hood. ("korntunnel")

And the rear missing the elevator.

Modell 3.102? Or 3102 or 310-2...nomenclature is confusing.

The 12 round magazine.

The magazine well.

Inserted into the rifle.

Low power...although Tom Gaylord had similar velocities...

One screw removed...

And the middle screw...

And the front trigger screw.

Shorter screw is the front screw.

The action.

The magazine well.

I pried off the cover.

The pin for the bolt pushes out. I straightened the bolt and pulled it free.

Pin holds the end cap.

The somewhat complex safety knob end...

I pulled out the trigger group. The piece of sheetmetal also pulls off. I believe it is a cutoff to keep the gun safe when cocking.

The parts removed so far. I have no great incentive to disassemble the trigger group.
More to come...

Installing a Morgan Adjustable Pad on a Beeman R1

Completely struck out with that vintage Morgan pad. The base had been fitted to something pretty svelte. So, that's just one more reason to keep buying more airguns. Given enough new airgun purchases, the old pad will eventually fit one of them.

Since I was still in Morgan mode, I decided to fit the new model Premium Morgan I got from Nick a while back. Making the gun selection wasn't so easy. At least four or five different rifles were candidates. Eventually, I decided to fit it to a .22 cal Beeman R1. I consoled myself that I'll just eventually buy more pads.

Started by removing the old pad and white line spacer. Bolted down the new base using the existing stock holes. The base appeared to be well centered so I didn't need to drill new holes.

Above and here you can see the overhang. The aluminum needs to be ground away to fit.

I'll try to carry the contour of the buttstock through the lines of the base.

Traced the stock profile onto the base. Remember this is the gun side, so any angles cut need to flare outward slightly--especially at the heel where the angle is more severe.

I blackened the area with a magic marker. I know that using the pencil to trace will leave the plate a few hundredths or more larger all around. So, I guess I'm starting slow.

Started at it with a file. Rubbed the file with chalk first to help prevent the aluminum from clogging the teeth. Was only marginally successful. Used the file card to clean quite a bit then gave up and went to the bench grinder. Grinding aluminum on a bench grinder is probably best avoided. The wheel loads up with aluminum very quickly which minimizes the cutting action. Then there's the danger that the aluminum will heat and expand in the pores of the wheel and cause the wheel to shatter in use. I'd like to avoid that. Dressing the wheel frequently helps prevent excessive loading. A belt sander or a sanding drum with a coarse grit (something like 60) would have been a good alternative.

After the initial shaping. Guess I could have been more aggressive on the removal.





Coated the base in dykem layout fluid this time...

and reinstalled. Found a sharp scratch awl and scribed a very fine line around the perimeter.

As always, click any pic for an enlargement. The scratched line is pretty evident.

Went to the drill press next with that 60 grit sanding drum. Kept the base angled slightly to create the taper to match the buttstock. I did most of this by test fitting and by eye. There are tools from Brownells to make this easier and take some of the guesswork out.

Looked really close, so I block sanded it to 220 grit.

Then used a 3M fine finishing pad to remove the scratch lines leaving a nice matte finish. This single step took about 3 minutes.

It'd be fine to call it quits here and get on with your day. The pad is fitted alomst seamlessly over about 80% of the perimeter.

Still, I want it right.

The black line is the only area that still stands proud.

Back to the sanding drum to work that area down slightly. Then the 220 grit sanding block and again with the 3M pad.

When I was satisfied that it looked right, I hand buffed the sides with Mothers Mag and Aluminum Polish.

Final installation--don't forget the all important adjusting bolt. The lines/angles look good on the stock-to-base transition. I like the angle at the toe.



Pad installed high.

And at the lower end of the travel.

One down, several more to go.

Fixing the Crosman 622, Part 2

This is one of those posts where I'm reminded how much I have to learn about working on airguns...

I set up the receiver half with the valve and tube in place.

Carefully aligned, I spotted for one of the cross pin holes with an end mill.

Then I tried to drill through before reaming to 1/8"...disaster! The tube hole started getting oblong as the drill drifted towards the outside of the tube...

I forgot to clamp the piercing assembly in place...if I had just put the piercing guts in and clamped with an empty CO2 cylinder it would have stayed put. But I didn't. At least I caught it before I was all the way through.
This highlights why I buy "beaters", guns that other guys have given up on. If (when) I do screw up I haven't caused some horrible historical loss to the world supply of collectable airguns. Chances are anyone else repairing it would have swapped out a valve assembly that didn't have a big chunk out of it. At least that's what I tell myself as I weep my self to sleep at night.

So now what? Well I do have this hole in the underside of the tube...

I reamed it to 3/16"

Spotted through the valve body to the piercing assembly.

Then removed it and drilled down shy of the gas hole and reamed to 3/16" for a slip fit (not a press fit)

Of course that dowel pin is a little long. It should provide some extra insurance for the tube and piercing assembly.

Ground to fit inside the housing.

Here's how the spring goes on the feed pawl.

Small end against the bushing.

That screw, which I thought wasn't stock, but is, in place.

Finally I returned to the reason for getting into the gun...the spring that actuates the magazine index...that is where the end goes. You cock the gun while carefully keeping all the parts together with your hand then use a screwdriver to bend the long end of the spring under that boss.

Here's another view.

Otherwise it goes together in reverse of disassembly. Use a pin to hold the trigger in place before you put the housing together and screw the trigger pivot screw in (pushing the pin out).

Well it works! I've shot through two CO2 cartridges so far and it held gas for three days in a row.
I'm getting 380-390 fps with 14.3 grain Crosman wadcutters which is about the same energy as the manual's quoted 375 fps w/ 15.5 gr. pellets. It is possibly one of the most fun air rifles I've shot. You can shoulder the rifle and "blam, click clack, blam, click clack, blam..." You get the idea. Maybe I'll work up the nerve to try porting it and using a heavier hammer spring someday for more velocity but as a plinker it's perfect.