Feinwerkbau Sport air rifle: Part 8

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7

Feinwerkbau Sport air rifle
FWB Sport air rifle.

This report covers:

• Assembly
• Lubrication
• Testing the rifle
• Crosman Premier lite pellets
• Air Arms Falcon pellets
• Evaluation to this point

Today, I’ll finish the tune of the Feinwerkbau Sport air rifle, and then we’ll test it. When we ended the last report, we had looked at all the parts and cleaned off the excess gear oil.

Assembly
Now it’s time to assemble the rifle. I looked at the trigger assembly that receives and holds the piston rod when the rifle is cocked. It’s very similar to the 124 trigger, but I can see refinement in fit and finish. This won’t be an easy trigger to modify, but it’s so nice as it comes from the factory that this isn’t an issue. I did not lubricate the trigger before assembly, but I did dry off the gear oil.

Feinwerkbau Sport air rifle trigger assy
A lot of similarity with the FWB 124 trigger, but these parts are finished better.

Feinwerkbau Sport air rifle trigger assy2
Underneath, you can see the trigger parts more clearly. Very similar to a 124 trigger except for a much better finish.

Feinwerkbau Sport air rifle trigger assy3
The piston rod enters the trigger assembly here to catch the sear and set the safety. The flat bar on top is the safety.

The barrel was placed back into the action’s forks. Other breakbarrels fight this assembly because the pivot bearings slip out of place as the baseblock is slid into the action fork, but the Sport’s bearings fit so well into recesses that there’s no movement. Once the pivot bolt is in the hole, it’s tightened. Then, the locking screw is tightened in the end of the bolt. With the Torx fasteners, it’s so easy to do!

Lubrication
All metal parts that slide against each other got a coat of Air Venturi Moly grease. That would be the tail of the piston, the beveled edges of the cocking shoe and the piston slot they ride in. I used to pre-coat the compression chamber with a film of moly paste, but I’ve found that the moly that transfers from the piston seal is sufficient to do the job if the chamber walls are finely finished.

The piston seal was coated, as well. And the piston rod also got a coat of moly. The piston was slid back into the spring tube, and this was where I noticed that the piston seal is possibly on the small side. You usually have to fight to get the piston seal into the tube, but this one went in easily. An aftermarket seal might tighten the piston just a bit.

I’m not going to make parts for the gun, and I wanted to stay on the light side with the lube, so I buttered the mainspring with Beeman Spring Gel, which is no longer sold, but which is a red synthetic grease of medium viscosity and tack. Since the spring guide is so loose on the mainspring, I probably should have used black tar on that part, because it’s very viscous and tacky. Instead, I used a coat of Beeman Mainspring Dampening Compound — another obsolete white synthetic grease of higher viscosity than Spring Gel, but lower than black tar.

Both these greases are no longer made, but you can find acceptable substitutes in the synthetic greases at any good auto parts store. Look at wheel bearing greases, especially. If you’re going to tune airguns, finding the right lubricants is very important, and automotive stores plus the farm supply stores are great places to look.

Feinwerkbau Sport air rifle mainspring lubed
I butter the front half of the spring with Spring Gel, then insert it into the rifle and butter the back half. That way, I don’t have to hold it.

Feinwerkbau Sport air rifle spring guide lubed
The spring guide was heavily coated (buttered) with Beeman Mainspring Dampening compound. It’s thicker than Spring Gel but can also rob some power when used too heavily.

The rifle went together exactly the same way it came apart. Everything fits together so well on this airgun! And the Torx fasteners do their job with such precision. Other airguns have them in some places — the Sport uses them everywhere. I wish you could see this for yourselves. I don’t say any of this to justify the cost of the rifle, but I do wish that more air rifles were made this well!

Testing the rifle
With the rifle together, again, the first thing I wanted to do was test it to see what had changed from the tune. I cocked it and checked the tension on the pivot joint. It was perfect — just as it had been before disassembly. The barrel stays wherever it is placed after the rifle is cocked, which is what you always strive for. That assures the breech will remain closed when the rifle fires.

Cocking the gun seems no different than before. The action is almost silent and everything works exactly as it should. That was true before the tune, as well. What I’m saying is the Sport isn’t a rifle that can be cocked without setting the automatic safety every time, as many other spring rifles can.

I fired, and could tell right away the gun felt much more solid. There’s a lot less buzzing in the powerplant each time the rifle fires. And because thick viscous grease was used instead of oil, it will remain this way for a long time.

But, I must be honest. This lube tune did not remove the last bit of buzz. If this were my personal rifle, I would certainly make a new spring guide and also look into buttoning the piston. I might even look into a new piston seal, as this one could be tighter. The buttoning might take care of that, though, so I would do that first and test the results.

Crosman Premier lite pellets
The first pellet I tested was the 7.9-grain Crosman Premier dome. Before the test, this pellet averaged 852 f.p.s., with a 21 f.p.s. spread from 841 to 862 f.p.s. After the tune, the same pellet averaged 878 f.p.s. with a 35 f.p.s spread from 861 to 896 f.p.s. The smell of burning oil told me the gun is still burning off some excess lubricant. I will, therefore, not claim a velocity gain for this tune because of the demonstrated dieseling. I’ll just say the rifle is performing back at the same level as before the tune.

Air Arms Falcon pellets
Next up was the Falcon dome from Air Arms with a 4.52mm head. Before the tune, this pellet averaged 928 f.p.,s., with a 19 f.p.s. spread from 919 to 938 f.p.s. After the tune, the same pellet averaged 953 f.p.s. with a 10 f.p.s spread from 947 to 957 f.p.s. While it does look like there has been a velocity increase, I had 2 shots at the beginning of the string that broke the sound barrier. One was 1029 f.p.s. and the other was 1062 f.p.s. I disregarded them because the velocity settled down so quickly and was then so very stable. I think it’s still too early to say the velocity has picked up. Maybe after 1000 shots we might get a better sense of what’s been done, but I won’t be testing this gun that long.

H&N Baracuda Match pellets
Perhaps the final pellet I tested tells the true story. It was the H&N Baracuda Match with a 4.50mm head. Before the tune, this pellet averaged 708 f.p.s. with a 20 f.p.s. spread that ranged from a low of 699 to a high of 719 f.p.s. After the tune, this pellet averaged 709 f.p.s., so not much difference. The spread after the tune was 15 f.p.s. and went from 703 to 718 f.p.s. I must mention that the gun doesn’t sound very good when shooting this very heavy pellet, so I only did this as a test.

Evaluation to this point
The FWB Sport needs a heavier lube than I used, or it needs more than just a lube tune. The spring guide needs to be replaced, first and foremost. After that, the rifle might shoot smooth. If not, the piston could be tightened with buttoning.

I don’t know if I’ll go back to the 50-yard range for another test, or not. Logic tells me the accuracy shouldn’t change. But now that the rifle shoots smoother, I find myself asking, “Why not?”

87 thoughts on “Feinwerkbau Sport air rifle: Part 8

  1. BB
    What color is the moly lube. Black or blueish color.

    We use a blue colored moly on some things at work and its pretty slick when you rub it between your fingers. It feels like it gets slicker the more you rub it.

    Then we have a black color moly that we use on exsposed gears. Its kind of tacky feeling.

    I don’t know what type each is. We get cardboard tubes of it that will fit in caulk guns. The place is a lubricant company and the tubes are blank.

    I just wondered what type you have.



      • Does it feel slick to the touch or is it sticky.

        The color probably doesn’t mean anything. I just know what the stuff is like that we get. But the black that we get is a no,no for any kind of slip fit tight tolerance stuff.

        The blueish stuff does look black until you spread it out thin then it starts looking blue. And it is a much thinner viscosity. If you put it on two metal surfaces it definitely slickens the movement up.

        I just wanted to know because you cant really tell by a picture what the lube feels like. And plus that is some of BB’s old stash and you may not be able to get it anymore.

        So I didn’t want to get something and it not be the same and not do the job like it was intended to do.



          • Wonder what the stuff in my basement is like… Besides looking graphite black..

            When I moved to the PRCa back in 1980, one of my first purchases was a grease gun, and a case of tubes for it… I still have 5 unopened in the basement (tube 6 went into the gun a few weeks ago, when the lawn tractor needed the 8-hour servicing).

            Label implies it is a molybdenum disulfide LITHIUM grease (“moly e.p. 2 lithium” yes, the font is lowercase). I recently looked at the stuff available in a department store and saw nothing I’d consider similar. Forget the moly — I don’t think they even had lithium.


        • So called moly lubes can run the gamut, and lubes can use the term”moly” legally even if they are only 3 to 4% Moly disulfide. The actual lube advantage with such a low percentage of moly is dubious at best. The best molys for airguns aren’t even a grease per se, but rather a paste consisting of 60% moly or more. Real moly disulfide is a dark grey almost black color, so if you are seeing colors in your grease-there is VERY little moly in it.


          • RB
            Our lubricant supplier at work can actually send us molybedumdisulhpide. Its more of a blue color and they suspend it in a thin liquid.. What we get anyway. I use to mix me up a little concoction for my Radio Control Nitro engine on my Pylon racing planes. I swear it made them RPM a couple thousand rpm’s faster. So I thought anyway. 🙂

            Have you tryed any teflon lube. Its kind of hard to keep mixed in a oil base though. It wants to separate. But that’s pretty slick stuff.


            • Yes I have. In fact, my piston seal lube is a blend of synthetic grease and pure PTFE in the form of an ultrafine white powder. Mixed together you get a really slick white paste that doesn’t dry out and its better on piston seals than moly (moly is best suited for steel to steel applications).


          • Just be careful. Honda sells a 60% Moly but I found this warning on a web site that sells it: Do Not use Moly 60 on plastic, especially styrene resin. Moly 60 will damage (erode) these materials.


          • 3% to 6% Moly is normal for heavy industrial equipment (and autos that call for it) . It very effective for what it’s made for. The “moly” forms “plates” that slip over each other. The high 60% moly is usually a paste. It would not work well in autos. That said, I believe it would be great in an air gun. The thickeners keep the grease in place. They are “soaps” that act like a sponge that hold the lubricant in suspension . Lithium, Aluminum complex, Polyurea and Calcium thickeners are the most common, with Lithium and Lithium complex being the most popular.


            • Also, most colors in greases mean nothing, just a die. Same with the red in ATF and the purple in Royal Purple. Moly itself is black/lead grey in color. So if you buy a moly (Molybdenum disulfide) grease that isn’t black/grey/dark silver in color, it just means it has a lot of die in it.


        • I was just looking at what moly was available in local auto parts and the only one was moly/graphite lube, which might explain the gray color. They did not have any other variants of a moly lube besides one being in a mineral oil base and the other refined petro distills,,, don’t want to use that one.


        • GF1,

          Like BB said, you do not want to touch it if you can. Not only is it difficult to wash off, but it will get on everything! It will readily transfer to every surface within 100 feet!



  2. Sounds like a success, to an extent. I’ll be ready to jump back into my QB-36 once it warms back up and I get this Regal dialed in and I’d like to button it’s piston. Where’s a good place to get some? My most hoaky idea was weedeater line melted and sanded to fit but I don’t want ’em comin’ loose



      • Siraniko
        Thanks for posting the blog about “buttoning” a Webley piston. I have often heard it mentioned on this blog, however, this is the first time I have actually seen the process in such detail. I can see how this would be an advantage over the unbuttoned factory version.
        Ciao
        Titus


      • Siraniko
        Glad you put the link up.

        I have always thought that the transfer port size is the life of a spring gun. I mean most people know not to dry fire a spring gun. The smaller size transfer port should help cushion the piston. Plus could actually speed the pellet up.

        I know some people have different ideas but I believe a heavier pellet helps the piston last in a spring gun. But of course too heavy causes other problems.

        That word balance comes to mind again.


        • Hey Gunfun1

          Agree about the transfer port – never messed with that and left it “as designed” but when I had a springer apart I would lightly chamfer the piston-side of the port (by hand) and then polish the chamfer with a sharpened wooden dowel doped with some valve-grinding compound. Used a hand-crank drill for that operation. I theorized that the airflow over the polished edge of the transfer-port would be lest turbulent. Could never prove it improved the guns’ performance but figured it wouldn’t hurt and it only took a couple of minutes to do.

          Guess that it is one of my quirks… Things that are supposed to be sharp must be VERY sharp and everything else gets de-burred. LOL!

          Vana2


        • One thing about trying to reduce TPort size, is that you can only make air move so fast. With conventional means, the airspeed moving thru a transfer port cannot physically exceed the speed of sound. As you noted, balancing is important. You can find the optimum port size when the port diameter and length provide just the right duration of pulse combined with the proper force( velocity and volume of air).


          • RB
            Same as when porting heads on a race engine. Bigger is not always better.

            I sure messed with a lot of port sizes and length and valve sizes on engines. Then see what happens when you start getting into 4 angle valve jobs. The extra angles will actually speed up the air flow and allow for a camshaft that has a smaller lift an duration on the camshaft profile.

            In other words if you apply that to air gun transfer ports you can get that venturi effect. Kind of like if you have a lead in chamfer on the piston side of the transfer port then a medium size thru hole with a chamfer that meets the barrel lead in were you load the pellet. That should speed up the air flow to the pellet. So in a since you could have a transfer port that was port matched to the guns barrel.





  3. Does the automatic safety act as a sort of anti-beartrap mechanism? Not that I would trust it but some companies label their automatic safeties as an anti-beartrap mechanism.

    Shooting it at 50 yards after the tune seems to be the best way to demonstrate how much better the owner can expect to perform after tuning this rifle. If the rifle shoots the same at 50 yards the only reason to tune is to eliminate the buzz. If it shoots better, then a tune is definitely needed to extract all the performance out of this rifle.


  4. Hello bb
    Have you started on the heavy weight pellet test we spoke about three weeks ago
    How is it working out or have you decided it would not be very interesting or not worth the time and effort
    Please advise regarding this as I am very interested in the subject
    Thanking you for your assistance in this regard


  5. BB
    Why not another 50 meter test indeed. I believe I requested an 8 part blog at the beginning of testing this FWB, and now I eagerly await for part 9. My Mother always had a “saying” for almost every occasion. Something like “nothing ventured, nothing gained” comes immediately to mind, and might apply to your shooting a second round at 50 meters with a slightly tuned FWB. The fact that the gun is still burning off excess oil could be a factor on the size of groups. This has been an education to me regardless of group size. I’m liking everything about this gun. Details most buyers will never see, such as the barrel pivot joints with recessed bearings. Its this attention to detail that has me wanting this gun, even if the price be the equivalent of two HW95’s/BeemanR9’s. It doesn’t get any better then this.
    Ciao
    Titus


  6. I probably shouldn’t even post this. But after seeing the pictures of the last two days of blogs about the FWB Sport I see this gun was produced with quality in mind.

    I would like to know what types of machines they used to produce the parts. The parts could of been made on the same types of machines that we have in the machining house that I work at. The majority of the machines we have came from Europe and they now have a USA based shop next to our old building in St Louis Mo. since somewhere around the 70’s.

    They are called Hydromat rotary transfer machines. Been working on them since the early 80’s. I guess I can put a link up of what they are.

    Click on the video. These are the machines I started out running then setting up and now a technician. I mostly make pieces in the tool room now to automate the machines and make different grippers and such and rebuild valves and such.

    http://www.hydromat.com/



    • SOME NICE MACHINERY THERE! I used to work on the Japanese machining centers such as Asahi Okuma’s and Hitachi’s. Plus Monarch machining centers, etc. Years ago I made gun barrels for a living and used an HES Arnault French tracing and profiling lathe to machine barrel contours to customers specs. Back in 1980, that was a fairly high end machine LOL.


      • RB
        The machines now have what they call Epic stand alone CNC units that can be placed at any of the 12 or 16 horizontal machining stations. And we can have from 1 to 8 vertical stations.

        They all machine at the same time and it has a station that will go in and grab the part and unchuck it and spin it around and load it back into the chuck or collet. Its called a inverter. So we can machine one side of the part flip it around and machine the other side.

        I don’t know if you looked on the Hydromat home page but if you go down about 2/3 RDS of the way down on the left you can click on the product’s that have been made.

        We actually made the 430 grenades 25 and 30 mm projectiles and the buffer body for the M16’s. I thing we made the bolt for the .50 cal. BMG sniper rifles. But it shows a lot of products.

        And it sounds like you had a cool job too.


  7. BB,

    You know you want to shoot it some more. Go for it! Why not? How often do you have the opportunity to play with a real nice air rifle? Most of the time they are OK at best. Then you have one like this show up at your door and you find ways to do an extensive test on it. I know I would find it difficult to pass it on.

    I truly do hope that this information is getting back to Feinwerkbau. It is quite obvious that they have paid such close attention to quality and detail throughout. Yes, I could buy one of these and tune it myself, but like they say on Monday Night Football, “C’mon man”.


  8. Hi BB, thankyou for doing this nice report and giving us some incite on the FWB Sport. Sounds so easy for FWB to make a tighter fitting spring guide it makes you wonder why they felt it should be loose. If you go for the buttoning of the piston would you also have to re hone the cylinder or is it that trued up and finely crosshatched. I wonder if in time and reading the reports they modify later models with tighter srpring guides, seals and add the very popular 22cal. Certainly a letter from you could help? MEant to ask-was that trigger steel or aluminum?




  9. Thanks for the clarifications between the Feinwerkbau target triggers and sport triggers. The Feinwerkbau triggers could not keep up with the likes of my Anschutz trigger without being extraordinary. To an extent, the categories are apples and oranges. You wouldn’t want a hair trigger like my Anschutz in a sporting situation. At every range session, despite my best efforts, I will prematurely discharge the trigger and blow the shot. Nevertheless, I think with the Feinwerkbau name, people can’t help wondering how much of that fantastic engineering would trickle down. Apparently, there’s a significant divide from the top level.

    Car enthusiasts, I need your help. With shooting, I’ve learned to vividly imagine guns that I will probably never own so that they almost seem real, and something similar is at work for cars. For a time, I was enamored with American muscle cars for their high horsepower and cheap price, sort of like the high value guns I like to buy. But then I read that these cars lack special engineering for handling at high speeds that are found in sports cars, and without this equipment, they’re only able to go straight. That was a real let-down since it seems like much of the fun of going fast lies in zooming around turns like the Nurburging rather than just going straight. So, I resigned myself to the Corvette Stingray for $80,000. But now I hear with the impending release of the GT350 Shelby Mustang that certain Mustangs have been able to beat sports cars on a track. This could be game-changing. Have muscle cars caught up with sports cars? And how could this be possible without the similar specialized and expensive engineering?

    Matt61



    • Matt61
      The Mustangs,Trans Ams,Z/28’s,AMC Javilins and others I’m forgeting did road race back in the day.1970 The scca(Sports Car Club of America) was big with muscle car road racing.
      The Trans Am road racing series was a real big thing with Muscle cars. One of my favorite muscle cars was the white with blue stripes 69 Pontiac Trans Am. Yep it was named after the Trans Am road racing series.

      And yes the modern muscle car wars is still happening and yes some of the old and new muscle cars did handle. They weren’t only fast in a straight line.



        • Ricka
          I know the Mopars old and new are cool. My buddy had a plum crazy purple AAR Cuda back in 78 when we were getting out of high school.
          It was a 340 6 pack 4 speed car. It ran its butt of and did the twistys good to. And what’s that new 700 HP Challenger called. I forget the name.

          And I had a few Darts in my time. A 69 440,4 speed car. And a 70 340 ,4 speed car. I liked the Mopars because they had that front torsion bar suspension. You could raise or lower the front ride height by a turn of a wrench. Way cool idea.

          Then you want to talk later model Mopar. I had a yellow 03 and a black 05 SRT4 with mods done of course. Them cars would turn and burn as well as go straight fast. How about mid 11’s @ 126 mph with the black 05.



        • Gunfun
          Pontiac is no longer a car company and I have heard no news of them being resurrected so how are we going to get a new trans am firebird form a company that no longer exist,

          BD


          • buldawg
            What are you talking about. I think you read Ricka reply about the new Trans Am.

            The only reply I made was about the 69 Pontiac Trans Am and the road race series.

            Is that what your talking about?



          • Buldawg 76 and Gunfun1 I had no time to look it up and forgot about it until now. Just looked it up and it appears to be a separate company using the new Camaros as the platform and they are going to be big money.



              • Buldawg76 I just looked at lunch real quick and sent you and Gunfun1 the message. I just googled new firebird/ trans-am and picked one of the first entries from a reliable looking source. There are multiple listings of the cars so plenty of info to keep you reading. I have had very little time for anything but work and taking care of my folks otherwise I would gladly find a good link for you.


      • I built a B Production SCCA Trans Am series Corvette for my buddy years ago and he won lots of races on the East Coast with it. Trust me, a street Corvette of that time was nothing like the car we put on the track. It cost more than $100 grand a year just to keep that car on the track and competitive. We are talking about the early to mid 70’s. I followed road racing into europe during that time and even went to several F1 Gran Prix’s..Monaco, Nurburgring, Zandvoort, Spa and Silverstone. Love the ‘Ring! We did some serious partying there for a few days. Some fine looking frauleins cavorting around that place! LOL


    • The old Mustang GT (5l v8) had a reputation for being a straight line car… The CHP made the mistake of buying an allotment of them for pursuit cars — and then having to retrain officers as they couldn’t corner with them. Not that they were “bad”, but just that the back end would come loose easily under acceleration and they’d spin out if trying to catch someone on a freeway interchange.

      Don’t know about current editions. The Dodge Charger that currently reigns in the horsepower wars might have some ability.

      If it means anything, back in the mid-80s, my measly FWD Plymouth Turismo 2.2 outcornered a Mazda RX-7. It was a scary happening after the fact.

      RX-7 was in front of me heading into work. We had a right-hand turn. I glanced down at my speedometer half-way through the turn (30-35mph) and when I looked up the RX-7 was NOT in front of me. I found it in my rear-view mirror, facing backwards, on the right side shoulder. Apparently he’d spun 180 and driven off the road in the time I was monitoring my entry speed.

      And I had cause to monitor it — the staged 2-barrel carb on that model had a fuel cut-off solenoid… Mounted horizontally… I often had the engine stall out taking right turns as the centrifugal force would close the fuel flow! {I also used to have disconcerting stalls getting onto freeways — it seems breaking 6000RPM triggered a governor that kill the engine until the RPMs dropped to 2000… Nothing like merging into 60MPH traffic, upshifting, and having the engine die}


  10. It would depend on the car. My son’s 2003 Mustang Cobra (Light Mods) handles well as built. Yet, it will just hammer you back in the seat with 425 rear wheel HP. 🙂

    Mike


  11. I remember that red spring gel. I had Beeman ‘accurize’ my fwb 124s back in the day and you could see the red gel on the coils through the cocking slot. AND….it buzzed prominently. It was pretty annoying. Yes, that’s how it was done years ago: you bought a new gun and paid extra to have them do a lube tune for you.


    • Air Rifle Headquarters was like that back in the day.

      I remember in the early 70’s catalog I had they would offer different tunes and would tell you the accuracy to expect.



  12. As you will see by what i say i am not nearly as experienced with air rifles as most of the people here and i have a few questions. First of all i have seen the little cartoon on the Pyramid site proclaiming that gas pistons are superior to spring piston, but i have yet to see any information as to the superior qualities of the spring piston guns. I assume that some exist or why else would RWS & FWB be making very expensive spring piston guns? I also am having a hard time figuring out what the FWB sport is intended to do as it does not seem to be a competition gun and as a 177 is not much of a hunting rifle at least not for any game bigger than a small rabbit. I don’ get exactly what the gun is intended for. Perhaps i am just not convinced that good open sights and a good trigger & what i assume is a good if not light barrel is worth the $900 price.


    • Probably the same market that the HW95 / R9 is intended for which is rabbit size and smaller game hunting, general quality plinking and informal target shooting. as we all know the HW95 / R9 has always been an incredibly popular all around spring gun for many years. I love FWB but my HW95 really does not leave me wanting to spend $900 on this new FWB as I purchased mt HW new for about $400 including shipping. Now if FWB drops the price in the future due to slow sales, I may consider adding it to my stable, however it’s still slightly heavy to be carrying around for a day in the woods whereas my HW is still within woods-carrying spec.


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