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Ammo A shrine built for a Feinwerkbau 124 – Part 13

A shrine built for a Feinwerkbau 124 – Part 13

by B.B. Pelletier

Part 12
Part 11
Part 10
Part 9
Part 8
Part 7
Part 6
Part 5
Part 4
Part 3
Part 2
Part 1

The November podcast has been posted.

Before we begin, my buddy, Randy Mitchell, who was also the outlaw, Dakota, from Frontier Village (an amusement park in San Jose, California, from 1961-1980) sent me a photo from over 40 years ago. I was Casey Jones, the engineer who ran the railroad at the Village, and Dakota had put an obstruction across the tracks out in the badlands. When I stopped the train, he jumped me at gunpoint and forced me to clear the rails. Then, he stole my boots and drove the train back to the station himself. How time flies!


Dakota forced me to clear the obstruction, then stole my boots and drove the train back to the station himself. I had to walk back!

Now, on to today’s report. Well, well. How the tide turns when you go to an airgun show! I went to Roanoke hoping to score an FWB 124 to tune and instead I picked up one to tune for somebody else. That’s usually a good thing, because when I tune for other folks I do a better job. I’m like the cobbler whose children are barefoot.

You’ll remember from Friday that this rifle is Mark Taylor’s, and I gave you an idea of how it performed. The cocking was too hard, plus there was a scraping or grinding feel to it. Well, once I got the guts out I found out what that was and why it happened. But, I’m getting ahead of myself.

The first comment I’ll make is that Mark’s rifle hasn’t been apart many times. The mainspring I removed looked like a 124 mainspring, except that it had 39 coils — and a standard spring I have has only 35. So, the spring I removed was much longer than standard. At least I think it’s longer. Heck, it’s been so many years since I tuned a 124 that I doubt I know anything for sure anymore.


Looking through the cocking slot before disassembly, you can see that the mainspring has been coated with moly grease.

The second comment is that Mark’s rifle had the strangest lubrication I’ve ever seen in any spring rifle, and I include my older San Anselmo rifle in that observation. My gun was tuned back in the day when it was standard practice to use an entire jar of Beeman’s moly grease on the mainspring of a 124. When I took that gun apart the first time, I was scraping grease from everywhere! Had I known how full it was, I could have called Mike Rowe and gotten him to put it on his Dirty Jobs TV show.

In contrast, Mark’s rifle was almost dry inside! Only the mainspring was coated with moly, and it looked like a smear of lithium grease might have been applied to one spot on the back of the piston. As a result, the piston was touching the top of the spring tube when the gun was cocked and had galled (made shiny by removing a small amount of metal) a large area that wasn’t too deep. It wasn’t serious, but it also was never going to get any better.


This is how the piston looked immediately after removing it from the gun. There’s no lube on the seal!


This is the back end of the piston, called the skirt. As you can see, it has next to no lubrication.


The scraping, grinding feel came from this area. Those two bright lines are galled metal, where the piston skirt scraped against the inside of the spring tube. The damage is minor and correctible with the proper lubrication.

I discovered this lack of lube when I cleaned the inside of the spring tube. It was practically dry and grease-free in there. If I had tuned it, there would have been a lot of moly burnished into the metal and the cleaning patches would have come out black instead of white.

Using moly grease on the mainspring isn’t the best thing when you want a smooth shot cycle. That’s where Maccari’s Black Tar comes into play. A dry piston isn’t the right thing for this gun, as evidenced by the galled metal. I lubed the front and rear of the heavy 124 piston with moly grease. Gene Salvino, Pyramyd Air’s tech manager, recommends using lithium grease on their piston seal, but I used moly on this one because of the galled metal.

The piston seal that was in the rifle looked to be in fine shape. Since this was supposed to be a test of the new Pyramyd AIR seal, I removed it anyway. I’ve never seen another one like it and have no idea where it came from.

I also noted that the baseblock bearings weren’t lubricated with much of anything, which might have added to the cocking effort. Also, the barrel pivot pin was dry. I spread moly grease on both the bearings and the pivot bolt before installing them in the rifle again.

I selected an old Maccari Deluxe tune kit for the rifle. This kit drops in, but is made so perfectly that the mainspring goes on the spring guide like it was nailed on. That’s tuner’s slang for a very tight fit. The spring diameter expands when it’s compressed lengthwise, so the fit isn’t as tight as it seems when you install it. There was also a Delrin spacer for the spring guide that put a little more tension on the spring.


This is how to lubricate a 124 piston correctly. Both the front and rear of the piston can contact the other metal surfaces inside the gun. The center of the piston is smaller and cannot touch anything. Besides this, I also burnished moly inside the spring tube before installing the piston.

All metal-to-metal contact surfaces except for the outside of the mainspring got a coat of moly grease before the gun was assembled. The outside of the mainspring was buttered with Black Tar. Then, the gun was assembled in reverse order from disassembly.


This is how I “buttered” the mainspring with Maccari’s Black Tar mainspring dampening compound.

On to shooting
The proof is in the shooting, and the first time I cocked the assembled rifle it worked as it should, which doesn’t always happen. I noted that the cocking effort didn’t seem to have decreased much, but the cocking cycle was now as smooth as it should be. Then, I shot the rifle.

Wow! What a beautiful tune this is. Not only is all vibration gone, but the forward recoil I had noticed disappeared, as well. The gun just sort of pulses when it’s shot.

I then measured the cocking effort and was stunned to find it had increased a pound to 28 lbs. of effort. Personally, I think it’s too heavy for a 124, but the smooth shot cycle is too nice to ignore. Let’s see what is does over the chronograph.

Crosman Premier lites
The 7.9-grain Crosman Premiers averaged 744 f.p.s. with this tune. The spread ranged from 736 to 750 f.p.s. That’s a little tighter than the original tune, and much smoother. The average muzzle energy was 9.71 foot-pounds.

RWS Hobbys
RWS Hobby pellets averaged 784 f.p.s. The spread went from 776 to 793 f.p.s. Again, a slightly tighter spread than before. The average muzzle energy was 9.56 foot-pounds, and a super-smooth shot cycle.

JSB Exact 8.4 grains
JSB 8.4-grain Exact domed pellets averaged 723 f.p.s., a surprisingly low figure. They ranged from 713 to 730 f.p.s. and produced an average muzzle energy of 9.75 foot-pounds. They shot just as smooth as the other two pellets.

What to do next?
This is a toughie. The rifle is cocking and shooting extremely smooth right now, but the cocking effort is a bit high. Mark, the owner, says he doesn’t mind that, as long as the gun shoots smooth, which it definitely does. I’m at the point of a decision that I’m going to let Mark make. I feel certain that the Black Tar on the mainspring is what’s slowing down the gun just a bit. As tight as the mainspring fits, it probably isn’t necessary. Still, the gun does shoot very smoothly, and almost all of the forward recoil seems to be gone, as well. From a shooting standpoint, this is a fine tune. I’ll let Mark decide.

If he wants more power for the cocking effort, I would remove the Black Tar and lube the mainspring with moly grease. But, if he wants a super smooth shot cycle, we have that right now.

Mark, what would you like me to do?

52 thoughts on “A shrine built for a Feinwerkbau 124 – Part 13”

  1. BB

    He stole your boots and your train at gunpoint, and then made you walk back to the station? It sounds like this Mr. Mitchell doesn’t play nice. I don’t see Mac ever doing anything like that. Should have made ol’ Randy eat hot lead from your Colt.

    Those had better not be Edith’s good bath towels.

  2. B.B.

    The contact surface on the back of the piston skirt looks square and flat with sharp edges at front and back. Is this a lighting trick or did it really look that way?
    Did you smooth it up to remove sharp edges before you put it back together?

    twotalon

    • twotalon,

      If I understand you correctly, the back of the piston is larger than the middle body. The piston is a welded assembly. No, I didn’t remove any sharp edges, because on this rifle they were not the problem they can be with some guns. Maybe the person before me took care of them.

      B.B.

  3. B.B.
    Do you have any A/A falcons 7.33 gr. or JSB 7.33 gr. to try in that 124? My 124 loves those Falcons and they run I would say about 30 or40 F.P.S. faster than the Hobbies.

  4. Morning B.B.,

    A most interesting series on the 124. I’ll bet you that Mark will say thanks a lot for the offer to reduce the cocking effort, but no thanks. The gun is just fine the way it is.

    Bruce

    PS The composition of the picture is great. Love the framing, and the shadows in the foreground. It almost looks like the roof of a building in the back ground. Is it?

    • Mr B,
      I can answer your question and you may find this hard to believe but you’re looking at the smoke stack of the train. They were large funnel shaped stacks. The one you see has a cap on top with a smaller diameter exit hole. I don’t know what the benefit is of having the largr funnel then reducing it smaller.
      -CJr

  5. BB

    Like I said in a comment last week, following this FWB 124 series has been a blast. And being able to “participate” has been a bonus. Thanks for volunteering to tune my recently acquired rifle. You weren’t kidding when you said you’d get to it quickly.

    So, decision time…

    It’s not a difficult one. I’m sticking to my original thinking that a smooth shot cycle is my priority. I don’t mind the heavier-than-usual cocking effort. Heck, compared to the rifle I sold (my Beeman Kodiak) to make room for this one, 28 pounds will be a breeze!

    I can hardly wait to start shooting this thing, and hope that smooth cycle helps me (and the gun) realize the kind of top-notch accuracy for which these things are known.

    Again, thanks for doing this. I owe you one — maybe a guest blog on my accuracy findings!

    Mark

    • Mark,

      Okay, then it is settled. The tune is done.

      One last thing I would ask. When you receive the rifle and shoot it, would you please critique the feel of the tune for everyone? It doesn’t have to be a guest blog, though you are certainly welcome to do that, but at least an observation of how the new tune compares to what you remember the rifle feeling like.

      B.B.

      • I’m more than happy to do that, BB.

        Of course I didn’t shoot the gun much, opting to hold off once the grating during the cocking cycle became so serious. But I did put enough pellets through it to get an idea.

        Mark

  6. BB … man, I remember Frontier Village, and Santa’s Village and Winchester Mystery House and, and…

    Dad worked at Alameda Naval Air Station and we lived in Castro Valley/Hayward area.

    Is that home territory for you as well?

  7. Does this FWB has a straight compression chamber or a tapered one? How about the new seal, has it the same dimensions as the original seal? Is it harder? Does it fit tighter?

    A smooth shooting airgun is a nice thing. Now look for accuracy.

    • Markus,

      As late as this rifle is, the compression chamber is probably not tapered to the same extent that mine is.

      The new seal fits very tight. That’s best for longevity and for smoothness. It’s harder than the original seal (not the one I replaced) because that one was made from a too-soft material that will decompose.

      B.B.

  8. This series has definitely been an interesting one. It’s starting to look like it could work itself into a book. Lot’s of good info here.

    Was the bootless walk a regular thing? or just a onetime prank?

    ka

  9. Hi all,

    from this past weekend’s topic on my scope problems with the Benjamin Trail Nitro – Crosman said to send the scope to Warrantee so they can check it out. I asked them if the trigger from the Crosman NPSS would retrofit to this rifle and the answer was no – stock is different. Well, we have Charlie Da Tuna’s trigger in the mail so by the end of the week I’ll hopefully have a decent trigger. I have to tell you all that without this Blog and my education over the years, I would have been totally lost as to what was wrong with this rifle package. BB, and everyone else, please pat yourselves on the back for all the information you’ve generously provided to everyone else on this blog who first came here as a newbie.

    On another topic, due to windy conditions, I didn’t shoot the re-calibrated Marauder for accuracy or for possible spiraling of pellets so the blog on that rifle has to wait a bit longer. Sorry, BB.

    Fred PRoNJ

  10. BB,
    The Frontier Village was before my time there (there was “Roaring Camp” not too far away, though), but it looks like you had a good time. As you remarked in your comment to Brian, Mount Hamilton is worth the trip in every way, and the Winchester Mystery House sets the standard for offbeat ties to Santa Clara Valley before it became what it is today. My favorite lost feature was the orchard near me in the middle of Sunnyvale. That lasted a long time before it became a P.F.Chang’s and some other trendy stores in a strip mall setting. I will never eat at a P.F. Chang’s because of that. Orchard’s are much better neighbors than strip malls :). Its a shame you never went to the Orion store in Cupertino — you could have picked up another hobby for night time.

    The 124’s seem consistent in velocity to me — its not a bad place, either, in terms of power for a springer, just not what’s hip today. That’s how I tie in the picture to the past :).

    • BG_Farmer,

      One Mount Hamilton story. One fall day I cut all my classes and rode my RMW R27 up the Mount Hamilton rode. For others, that road is a narrow, winding paved road with dropoffs on one side. At that time there were no guardrails.

      Anyway, as I got within a few miles of the summit, I rounded the corner and was suddenly in a massive tarantula migration! Thousands of big hairy spiders were walking up the hill, crossing the road and climbing up the other side. Many were being crushed by the occasional car, but I was on a motorcycle. I slowed to just above walking speed and carefully picked my way through thousands of arachnids. I did not want to drop the bike there.

      They were gone by the time I came back down. Never seen one since!

      B.B.

    • BG Farmer
      Yup, I remember Walnut Creek when it was stil 1/2 walnut trees & groves.

      BB I rode my Bultaco (red toaster tank vintage) up that hill too, and many others that are now certainly part of suburban sprawl?

      Sucks to be a “geezer”

      • Speaking of the groves and orchards, I used to be hooked on dried apricots, so when they were in season, I’d buy a 5 pound bag of them right out of the orchard on my way to college and eat them in one sitting. I said I was hooked!

        What that much fiber did to my young system you don’t want to know, but suffice to say I didn’t need a colon cleanse!

        Those orchards are now called either the Pear- something-or-other or the Pruneyard!

        I went to Campbell High School one year behind Craig Morton, the Dallas Cowboy quarterback. Of course even he didn’t know who he was back then. After I was reassigned to Westmont High in my senior year, Campbell High was turned into a Junior College, which at that time was just a high school with ashtrays.

        B.B.

        • BB,
          The Prune Yard rings a bell. Instead of fruit, I mainly used to keep my system ticking with Thai and Indian food — the ultra-fast cycle time fit my schedule in those days :). My favorite Indian restaurant was a local landmark despite regular citations by the board of health — displayed like most places would display James Beard awards. I probably shouldn’t get started on different types of food — one of the few things I sorely miss on occasion.

          For the tourists to Sunnyvale (?!?) reading the blog, don’t forget the haunted Toys R’ Us, if it is still there 🙂 .

      • Hey partner,

        I remember Bultacos, also Ossas and Hodakas and Bridgestone motorcycles and Pentons and Yankees and American Eagles. How about DOT’s (had one), Velocettes and Cottons? Yep, that’s when we were men and you had to kickstart the darn things.

        Fred PRoNJ

  11. BB,
    Thank you for this blog series. I bought a FWB 124 and sent it off to Beeman for a supertune about a year ago. 1000 or so shots later, it has the same grinding feel and noise as this one did. It is also hard to cock, with more effort than my Diana 36. I don’t have a chrony, so I cannot give any numbers. So, I guess this one is due for a new tune. Was this a Monday or Friday tune? I thought a company like Beeman would do a better job than this. Thanks again for the series.

    Chris K.

  12. So the whole episode with the train was set-up for an audience to see, I assume. I hope Randy used Clint Eastwood’s line after taking your boots: “It’s maybe 70 miles back to the train station. I figure a man like you can make it.”

    There can’t be that many causes of heavy cocking effort. I would have thought before this report that spring stiffness was the only one. Any idea what the problem is?

    I had another once in a blue moon visit to the range the other day. No screw-ups this time which an achievement by itself. Actually, things really came together. Sitting there at the 50 yard line with my Anschutz rifle, Beeman rest bags, my dialed in spotting scope, a cool almost windless morning, and my regulation NRA targets with the bulls sitting in my aperture…it surely can’t get much better. Getting seriously set up in the prone position for the first time reminded me of the slugs in salt description of kids cocking Daisy 853 rifles in that position. I believe I looked that way just trying to work my single-shot bolt-action. The problem lay largely with the position of my spotting scope which I had to squirm to see through. Now I see why David Tubb spends so much time setting up his shooting position.

    This was also my first time using the M1 with a regulation target and my new 6 o’clock hold with the infinitesimal white line under the bull. Accuracy improved. However, my rifle was jamming with almost every clip. The surplus loads are just not working, so it looks like I’m committed to reloading.

    Working the 1911 at the pistol range, I discovered something that I had somehow insanely missed. Somehow or other my loose springer hold had crept into my hold for the .45. So I was limp-wristing the gun and then heeling it in compensation. With a firm grip, I put two eight shot magazines through a contiguous hole several times at seven yards. There was still a little bit of vertical stringing and the group was a little below point of aim. I’m not sure if that last feature was because of the sights or whether I was still heeling the gun. Unfortunately, these results evaporated at 25 yards, and I couldn’t even hit the target. MOA calculations say that I should not be that far off with a mere 18 yard increase in distance. Part of the problem is that I did not have the right targets with a clearly defined bull that I could see, but maybe it was also psychological. My confidence in the relevance of my 5 yard training distance took kind of a hit. No wonder I can hardly hit silhouette targets at 270 yards with my Savage 10FP.

    Matt61

    • Matt,

      Perhaps you missed it, but I did say that the metal-to-metal contact that caused the galling I showed was the definite cause of the scraping feeling. It was fixed through lubrication.

      The heavier cocking is all due to a more powerful mainspring.

      B.B.

  13. I enjoyed the story about you and Randy. Who’d have thunk it. I hear Six Flags Over Texas is hiring for next year… just sayin… 🙂

    My FWB 124D also needs a tune. I have had a kit for quite a while but just never got to it. I need to install it this winter once I get moved into my new shop I am having built.

    BB, did you ever write anything about the Gamo 68, 85, or the Survival rifle?

    Thanks,

    David Enoch

  14. Just purchased Titan nitro piston. Question I have is… How hard would it be to remove wooden stock refinish and replace. It looks like just 4 screws hold it all together. But since am not a gunsmith nor have I taken apart n fiddled with many or even any thought I would ask here. Thanx for any and all help

    • Usually its only three or four screws — take them out and see; I’m guessing the fourth screw is on the front of the trigger guard and probably doesn’t have to be removed. The only (rare) thing to watch out for is that some designs have pins in the action held in by the stock; don’t lose them when you pull it out.

      • Rock,

        very easy to remove the stock, as BG Farmer says. Remove screws on either side of stock towards front, then rear most screw outside trigger guard. The action falls right out of the stock. Be careful as there is a stock retaining loop of metal that goes around the very rear bolt of the action that helps to hold the stock in place. The two flat ears face rearwards and go against the stock, should you drop it and wonder how it goes in.

        Fred PRoNJ

      • Not gonnna do much just sand rough areas maybe darken stain. And hope I don’t mess it too bad and can put back way its supposed to be. Didn’ seem overly complicated least hope not lol. Thanx again

  15. I think I may have gone to Santa’s Village as a little kid, they had a frozen pole they called the North Pole right? Hokey 1960s kid stuff at its best. I think we went to Fisherman’s Wharf, and I remember being on some pier that had joints in the cement that had tar bulging upward by inches, my Dad had a fun game of lifting me up over the bulges, he could make anything fun. I was maybe …. maybe … 5. We were on a visit up from SoCal.

    The Pruneyard is still there, a bunch of restaurants right? Roaring Camp is still here, it’s famous for being the site of the yearly Musical Saw Festival which usually happens in August.

  16. Hi B.B.,

    I had a similar experience with Tarantulas, only it was in Eureka Valley, on my way to Death Valley. A long dirt road that absolutely tore up my flimsy Mazda pickup (I had sold my R50 when the kids came). But as I came down a hill, I saw hundreds of tarantulas running across the road. I just stopped an stared for about twenty minutes. My daughter, who was about 7 at the time, had wanted to go to the pet store and get a tarantula pet, and I thought about chasing one down and taking it home to her, but I wasn’t brave enough. Later, she got a guinea pig instead.

    We lived in Campbell then, and we took the kids to Frontier Village several times. But I think this was after you left. Now I’m retired and live in a smaller town on the Carquinez Straits.

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