Feinwerkbau 300 15,9 Joule power Tune

Discussion in 'Tips, tricks and tutorials' started by Edvard, Mar 27, 2016.

  1. Edvard

    Edvard New Member

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    Hi guys!
    I am new to the forum:)

    Just wanted to share a a project that I have been working on for a bit which is increasing the power output of the good ol Feinwerkbau 300, which I consider to be the best springer ever built, but its downside has been the lack of power for fieldtarget shooting

    I have currently taken it up to 15,9 Joules or 11,7 Foot-pounds, but I am playing around a bit with different springs to see where it likes it the best.

    https://www.youtube.com/watch?v=9Sz3W498BS8

    Current accuracy is this on a windy day at 30 meters or 32 yards without any flags from a benchrest position

    [​IMG]

    Cheers

    Edvard
     
    Last edited: Mar 31, 2016
    Willy hit it likes this.
  2. Jesim1

    Jesim1 Active Member

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    The accuracy looks very good to me. I'm not sure about power limits in Sweden, but with different pellets I get very different results power wise, so I'd be cautious setting a springer at 11.7fpe here in the UK as our limit is 12fpe, so I'd expect it to go over set that close. I'd definitely sacrifice power for accuracy, and certainly smoothness and usability in a springer.

    James
     
  3. mav78

    mav78 Professional Paint Stripper

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    How and what kit did you use to get to that power
     
  4. Edvard

    Edvard New Member

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    Yeah accuracy is the main objective at a higher power output than before which was around 7 foot-pound.
    what is the "average" power level of field-target springers in the UK to make sure they are within the limits?
    Here in Sweden the power limit is 7,3 foot pounds and after that we require a fire arms certificate, which I have, after we have that the skye is the limit for power output so no worries on that end;)


    There is actually no "kit" involved, I just did some minor adjustments on certain parts and some tinkering myself;)
     
  5. Jesim1

    Jesim1 Active Member

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    There is no "average" as the power is not logged to keep track of it, but you would be disqualified if tested and over 12fpe. On a personal note, I would reckon more around low 11s to high 10s for a combination of smoothness/power/accuracy - but it all depends on the gun. :rolleyes:

    James
     
  6. AlexS

    AlexS Active Member

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    What have been done? Double piston ring and heavy spring doesn't work. I imagine a shortened piston head, parachute seal, shorted piston rod and a little heavier spring.
     
  7. Edvard

    Edvard New Member

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    AlexS

    Well basically we are talking about a long stroking of the rifle.

    Cheers:)

    /Edvard
     
    Last edited: Mar 29, 2016
  8. poison dwarf

    poison dwarf BANNED

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    Video has gone :(
     
  9. Edvard

    Edvard New Member

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    Last edited: Mar 31, 2016
  10. skires

    skires Well-Known Member

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    I set mine at @ 11.3fp with Exacts.

    A decent springer like a HW77/97 or TX200 will do that sort of grouping at 30m.

    Is the recoil at that power more obvious than at 7fp?

    ... and are you wanted in Sweden?
     
    Last edited: Apr 1, 2016
  11. Edvard

    Edvard New Member

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    Hi there, nice to know 11,3 fp should equal around 235m/s or 770fps?

    I havent really tried target shooting with any sorted batch of pellets, so I dont know the accuracy potential of this rifle at this higher power level yet.

    The recoil isnt any different at all to be honest, but that is mostly dependent on how the transfer port is set up.
    I just wanted to have a go at this rifle since it is semi-recoiless and has probably the best match-trigger of all springers out there making it really easy to shoot.

    I am not wanted by the law I just put that song there in the video in order to troll some of the swedish airgun forums, its a long story but I should probably remove it and just have the video there unedited.:)

    cheers
    /Edvard
     
  12. skires

    skires Well-Known Member

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    It was more the hood and face covering than the music.:D

    A lot of shooters reckon that the 8.4gr Exact pellets fly sweeter at @ 770 - 780fps.

    I've seen a few videos and threads where people have increased the power on 10m target springers to use them in HFT and FT.

    I agree that they will have very good triggers but the triggers on the HW and TX are good enough if polished and set light.

    I wonder if ( UK and maybe World ) a non recoiling or semi recoiling rifle like the FWB would be allowed in the 'Recoiling' class ... or whether it may have to shoot in the PCP 'Open' class.

    Brian would probably know that.

    Another note re power. Jim Tyler who does lots of work on springer theories etc and writes for Airgun World often says it's best to have the power set to @ 11fp. I spoke to Terry Doe a long time ago and he has won championships in the early days of FT with springers, and he said he had his set to @ 10 - 10.5fp.
     
  13. Edvard

    Edvard New Member

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    Hehe yeah that hood might make it look a bit suspicious, but its mostly because I just want to be anonymous,:D
    Interesting to hear that a lot of people find that the pellets fly better in that spectrum of speed.

    I am coming from benchrest shooting with centerfire rifles, and dont have much experience with tuning air rifles, more tuning powder loads.
    In my experience you never know exactly where youl find the sweetspot. Its depending on so many variables, like quality of barrel, bedding and bullet type to just name a few. You can take two identical barrels with the same twist and chamber them the same using the same reamer to the exact same measurements, and they will still like different bullets and powders, and you still need to tune your loads with diffeent neck tensions, head space, seating depths etc.

    In my experience you can usually see that when you increase the velocity of a bullet the barrel will sway in a sinus curve going high and low and its allways best to set the rifle in any of the top or bottom nodes, because thats when the barrel is resting or moving the least.
    Is it the same with airguns? :)

    Ive heard that the Feinwerkbau 300 is still considered a springer in the worlds but not in the uk, not sure though.
    But if it is, I think it has quite an advantage over other springers since it is not hold sensitive and has a super trigger. in my opinion I dont think the CD or the Record trigger comes close in standards ;)
     
  14. SDplinker

    SDplinker Pellet testing...yawn

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    How was this achieved? I can't see how there's enough stroke for this power level. I discussed it extensively with several tuners. Custom piston? Chamber work? Just curious how you were able to pull it off. The cocking arm doesn't come back nearly far enough to achieve enough stroke...what am I missing??

    Casey
     
    Last edited: Apr 2, 2016
  15. skires

    skires Well-Known Member

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    Reduce the piston at the front end ... open up port ... stronger spring?

    A few have done this to get 9fp.

    I've no idea how you get 11.7fp out of the volume available.
     
    Last edited: Apr 2, 2016
  16. Edvard

    Edvard New Member

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    Hi guys.
    Well basically it is a long stroke conversion, its true that without that, you are never ever going to achieve this velocity. However I must say that I was quite suprised with this result, I never thought that I would be able to push it this high. I was expecting more like 10 fp tops.

    I dont want to go in to detail about how exactly I have gone about it, it is kinda a trade secret;) I have put a lot of work and money into this project that I dont want to give it all away at this point.

    However I found this thread after I was "finnished"
    http://www.airgunbbs.com/showthread.php?715541-Feinwekbau-300S&highlight=walther+stroke

    Bigtoe01 has some very good pointers there, even though I havent gone about it exactly the same way;)
     
  17. SDplinker

    SDplinker Pellet testing...yawn

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    Hats off to you if you've figured it out. Watching the cocking stroke of the arm I can't see how there is enough swept volume. But if it works it works. Love the rifles but wanted more power for field target.
     
  18. Edvard

    Edvard New Member

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    in my opinion I dont think I have figured that much out, all I did was that I went to town on the rifle with my calipher to get all the measurements and then thought about some ideas of what to change. ;)
    However after doing this trip once I have come to the realisation that there is still a lot more than I can change and try, I see it as an ongoing projekt to be honest.
    I can reveal that I am currently using the original piston ring as a seal, but I will try some other seal types and see how this affect things.
    If I can do it I think probably a lot of other people can do it to. The biggest problem is that you need good equipment that can work the hardened steel which the rifle is constructed of basically everywhere.
    The rifle is built like a tank;)
     
  19. bigtoe

    bigtoe Member

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    Well you had to get around the ratchet slot, so I am betting you sleeved the comp tube down, long stroked (which I have done also) and changed to either a HW45 seal at 22mm or you went over to an O ring to push the efficiency up as the stroke is very short (even long stroked) for 11.7fpe at 24mm.

    Everyone thinks the swept volume is to low, its nothing to do with the swept volume and everything to do with the stroke. Had 11+ easy now with 20mm pistons at between 80 and 85mm stroke in HW's and Diana's etc, it could go shorter BUT then the shot cycle starts to get too fast.

    Anyway...spill the beans, there are no trade secrets here ;)

    Edit, to explain further the piston in my 300 has an O ring seal now that comes well behind the ratchet slot, i machined the trigger block and the cocking side lever to allow massive amounts of stroke, the next plan is to machine down 25od 22mm id tube to 24mm od and sleeve the comp tube down, then reduce the piston dia to increaser the efficiency. The big issue however on the piston is spring room, it may end up with a new piston to allow a few extra coils in there.
     
    Last edited: Apr 5, 2016
  20. Edvard

    Edvard New Member

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    Hi Bigtoe, I was wondering when you were going to show up. :)

    Well of course I have "fixed" the ratchet slot, but not the way you think.
    I didnt sleeve it down, what I did was that I CNC-machined a new compression tube:D I also milled out a new smaller slot for the anti-bear trap so it works, which makes loading the ******* a bit "safer";) However in the video I hadnt fixed the beartrap yet because I had done my measurements wrong by some 10/100mm which made the bear trap unusable.

    However I think there is another "easier" way of fixing the compression tube, which i will soon try also without a sleeve. I think a lath-machine and some welding equipment will do the trick, and then som extra milling, some epoxy metal and some polishing;)

    I have some O-rings that I will try out as a seal instead of the original piston ring, however I am thinking more of using some hydralic seal cuffs in 95 shore polyurethane. I think they would probably seal better and resist wear from the high speed piston movement, what material are your o-rings in?

    cheers
    /Edvard
     

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