project lg 300

Discussion in 'Walther' started by hmangphilly, Jan 12, 2016.

  1. hmangphilly

    hmangphilly Not quite a full phil

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    found an error in the above pic......the piston on the absorber is the wrong way round .......sorry it must have got muddled up ........should be this way ....as below......

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    Dominator hammer compared to 10m

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    Dominator

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    10m

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    seal is different too

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    std soft material seat is thick at 1.6mm
    most will be replaced by harder acetal material .......i recently had fitting problems with acetal seat at 1.4 mm........it was holding the reg body away from the action .............1.3mm is the current choice

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    chamfer on the inside ..... the domi hasn't got that

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    10m and domi valve seat cavities tapered 10m and non tapered domi spigot

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    more to come , trying to find a std domi valve seat ..........
    but in the mean time .........
    here's the old style domi seat and valve ............

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    domi valves old.....tapered............
    and new ........flat .........
    lg 300 10m is same as flat , new style domi valve

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    then its springs , cocking levers, probes ,regs and barrels and whatever else we come across............
     
    Last edited: Mar 27, 2016
  2. sven

    sven Member

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    Nice project. The white dommie seals from Walther have become very expensive recently : 28 euro.

    cocking lever: is from hardened steel. Use a Dremel to cut off. Soften the corner (heat to dark red en slowly cool) where the handle has to come and tap for M4.
    probe: No need to change
    reg: I see a 16J reg in the picture :)
     
  3. hmangphilly

    hmangphilly Not quite a full phil

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    thanks

    Thanks for the kind offers of a std domi seal.

    That is very kind of the people involved ........good folk round here .

    I actually only wanted a std seal to illustrate the differences in sizes between the 10 m and domi .

    from memory the domi is around 1.85mm thick as opposed the 2.2 mm for the 10m in pic .
    if you could post up some pics with dimensions that would be great

    happily, this has prompted me to notice a further difference , the material of the std domi is a white ptfe ? and this blue 10m is quite soft rubbery / nylon type material.

    soft as it is, the valve has still formed an indentation......no matter ......it was never going back in.

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    time for a manicure me thinks:D

    thanks again fellas , I'm really ok for seals .....just haven't got a std one .......and 28 euros isn't going to happen:eek:

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    Last edited: Mar 25, 2016
  4. hmangphilly

    hmangphilly Not quite a full phil

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    same as domi

    While I'm at it,
    a quick measure of these bits appears that there is no difference to dominator .......if yours measures significantly different , i'd be interested ..............these are all from the 10 m rifle

    1/
    Depth of the firing valve return spring seat.........10m reg on lhs ........dominator on reg rhs

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    2/
    Valve.......10m and domi same.......2620847

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    3/
    Return spring.......10m and domi same ..............2163900

    length........take your pick.........

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    wire size.......

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    outside diameter....

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    Last edited: Mar 27, 2016
  5. NeilM

    NeilM Well-Known Member

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    Watching, goggle eyed.
     
  6. hmangphilly

    hmangphilly Not quite a full phil

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    hope it's entertaining Neil ,

    forgot a bit.......10m rifle again

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  7. NeilM

    NeilM Well-Known Member

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    As a Walther fan and shooter, and an inveterate fiddler (phar), it's fascinating.
     
  8. hmangphilly

    hmangphilly Not quite a full phil

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    we love a fiddle Neil :)

    found this to compare the part no. s to verify that parts are same / different

    Domi

    http://www.carl-walther.com/public/downloads/manuals/LG300_Dominator_System_2668190_l.pdf


    lg300

    http://www.carl-walther.com/public/downloads/manuals/LG300_System_2650711_g.pdf


    . ..........................................DOMI...........................................................................10M...........................................................
    35....hammer spring ...........2635119 Druckfeder 16J ...........................................2635119 Druckfeder ..................................SAME
    72 ...valve............................2620847 Ventil Valve ............................................... 2620847 Ventil Valve....................................SAME
    85 ..return spring................2163900 Druckfeder Spring, Compression................ 2163900 Druckfeder Spring, Compression....SAME
    16..sear.............................. 2646731 Abzugstollen Sear ......................................2646731 Abzugstollen Sear...........................SAME
     
    Last edited: Jan 12, 2016
  9. Steven842

    Steven842 " if yar crap yar crap "

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    i built a blue one from a 10m rifle and it shoots superb , all that required is required to convert just compare the two parts diagrams and replace the lg300 10m parts with dommi parts

    look forward to seeing a how to with this project ;) very interesting ;)
     
  10. hmangphilly

    hmangphilly Not quite a full phil

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    Steven ,did yours have this system

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    Last edited: Mar 27, 2016
  11. tugg

    tugg itchy trigger finger

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    A stabiliser ,how well does it work at 12/ftlb.
     
  12. hmangphilly

    hmangphilly Not quite a full phil

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    reg

    ive got a brand spanking 16j reg to use on this conversion .

    therefore absolutely no reason to get involved with regs ..........just bolt the new one on .....doesn't matter what the differences are , or how it works ..right ?

    yeah , right :eek:o

    reservoirs

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    10m reservoir first with dims to calculate volumes........

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    this dimension is common to 7.5j and 16j

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    so is this

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    and these 2

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    there's a short port connecting the 2 chambers i reckon its about 4-5mm long and 4mm diameter

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    Now the 16j domi version

    10mm longer

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    10mm deeper

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    Last edited: Feb 3, 2016
  13. hmangphilly

    hmangphilly Not quite a full phil

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    common to both is this , on the other half
    the volume of this part needs subtracting from the full volume of the reservoir to give the working volume

    this thread is 1mm pitch if any one is interested

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  14. hmangphilly

    hmangphilly Not quite a full phil

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    maths

    chief mathematician did some calcs earlier ........he'll be along later hopefully :):):):)

    all maths boffins welcome ............
     
    Last edited: Feb 3, 2016
  15. hmangphilly

    hmangphilly Not quite a full phil

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    oh yes here's a little curveball

    home made larger volume ......just for the hell of it :)


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  16. Steven842

    Steven842 " if yar crap yar crap "

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    Yip it did , and what I found was using the original probe as pictured (6ftlbs version ) with a 12ftlbs regulator set at 82 bar I struggled to get 12ftlbs and got a very inconsistent 11ftlbs max

    I then used the dommi probe (solid probe with no absorber ) and it was more than capable of 12ftlbs however the rear spring on the dommi probe has to hook onto something , the 6ftlb block only has an Allen screw in the rear which you'll find the hole is much larger than the dommi's one some engineering skill should solve this problem .

    Steve :D
     
  17. sven

    sven Member

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    Hi Phil,
    Did that math for you, and for myself :)
    7.5J regulator volume= 3.95 cm3
    16J regulator volume = 8.25 cm3
    Phil regulator volume = 10.69 cm3
    Sven/Sidney/Gert regulator volume = 13.73 cm3 :D

    But Jon Harris seems to need only some 4 to 5 cm3 at 85 bar to get to 12 ft/lb in the Anschutz !!!
    My current guess is that the 4mmx4mm port that connects the 2 chambers in the regulator is restricting the effective volume behind the valve. I'll get out my 9.5mm drill to correct thisl :)
     
    Last edited: Feb 4, 2016
  18. RobF

    RobF Administrator Staff Member

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    I had 4.2 and 7.5... but i wasn't writing things down and doing it in about 3 different windows while chatting to phil, so will double check.

    Question is, what are the advantages/disadvantages of the volume after the reg. We know from quick calculations that the whole of that volume is not swapped out on each shot, but if you use a 7.5J reg at 16J then a lot of it will. So it's understandable that they increased it. But the increase looks like an arbitrary 10mm length increase. So why not 20? Or is it that there needs to be a certain drop to get the reg to open again?
     
  19. Tench

    Tench WHFTA World Champion 2016.

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    I would agree that volume directly behind the valve is more beneficial, I have increased reg volumes with bolted on chambers which have little effect as the air path is too long and restricted.

    Rob, the lower the reg volume the greater the pressure drop, and the pressure that it drops to will be the driving force behind the pellet. Large reg volumes are much better, the limitation to volume is the pressure drop has to be sufficient to promt the reg to cycle every shot.
     
    Last edited: Feb 4, 2016
  20. sven

    sven Member

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    The Sven/Sidney/Gert regulator with 13.7cm3 volume gave me 242m/s or 16J at 80 bar reg setting in the LG400. I needed 85 bar before with the original 8.25cm3 Walther reg. Both with the same hammerspring setting.

    I had hoped to be able to drop the pressure to 70 or 75 bar with the 13,7 volume reg. Maybe that'll work when I drill the reg port.
     

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