A guide to stripping the Walther Dominatior

Discussion in 'Walther' started by RobF, Oct 27, 2013.

  1. RobF

    RobF Administrator Staff Member

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    This is meant as a guide. The site takes no responsibility for the info contained, you use it at your own risk.

    Some basic safety before working on the rifle.

    1) Make sure there is no pellet in the breech

    2) Engage the test (T) mode

    3) Remove the cylinder







    Removing the regulator and knock open valve.


    When removing the cylinder, as well as a small release of air from the cylinder itself it's not uncommon to hear some air escape the reg itself, either slowly or fast or not at all. Some regs shut off with a little click, some don't and some don't make any noise.

    If you're not comfortable with removing the action from the stock, then this is probably not for you. But assuming you have then you should have something like this.

    [​IMG]

    This shows a Mk2 reg (shorter, more silver in colour, with rings, as opposed to the older Mk1 regs which are more golden and lack the rings and are longer). Before undoing the 2 bolts marked with the arrow, understand that the reg will still be under some pressure with any residual air contained in it, and also that the knock open valve spring also creates some pressure, so undo the bolts slowly with a 4mm allen key equally keeping in mind that the reg will want to leave the action. It's not going to fly across the room, but all the same it won't just sit there.

    Also, if you haven't left the rifle on test mode, and have cocked it, then releasing the trigger will impart the hammer into the knock open valve with some considerable force, and it will send both the valve stem and spring out (once the reg is removed), possibly sending them under the nearest sofa, but possibly into an eye. Take care not to ensure this will happen.

    You should now see something like this.

    [​IMG]

    The spring you see may have stayed inside the reg, not unusual. If it hasn't simply pull it off. And you'll have something like this.

    [​IMG]

    The valve stem can be simply pulled out. It shouldn't need more than fingers. I avoid using metal tools on parts unless I have too. Although the stem is hard steel, it just saves burrs etc. You should now have this.

    [​IMG]

    This shows a black valve seat in place. The arrow marks where to put a pin or pick to remove it. If you use the inner or outer edge then you risk marking the alloy block itself. Not a major deal, but all the same, there's no need.

    There are 4 types of seal I've come across. 3 of them are here below.

    [​IMG]

    The bottom green one is the problematic soft seal originally fitted by Walther to early Dominators, typically those with a Mk1 reg. It's too soft and deforms with time and temperature leading to velocity fluctuations. Junk it. The black one is the one I found in this Walther. I'm not sure if it's aftermarket or an original item. It feels like Delrin or something similar. The top one is one of Nick (Zenith Rifles) Murphy's. I've been using these for some time and they are temp stable and don't seem to deform over time. So i'll be replacing the black one (which i've damaged as I removed it) with Nick's. Walther also do a white (PTFE I think) seal, which was deemed by tuners to be still too soft. So perhaps the black one is aftermarket or it's a new mk3 seal from Walther. Who knows?

    Because removing the seal tends to damage them, I don't do this unless it's not a type of my liking or it's deformed/damaged.

    So the action will now look like this with the seat/seal removed.

    [​IMG]

    As you have the reg off, you can always satisfy any concerns by getting someone with a reg checker to check it over. Each tuner has their ideas on how to do this and what they should be set at. Mk1's regs are deemed to be the unreliable ones, and harder to work on. Mk2's seem ok even straight from the crate, but tuner's opinions may vary.

    Reassembly is pretty much a reverse of the above. You should take care to tighten the reg bolts down equally. They don't need to be tight to the point of snapping, but they do need to seal the reg to the body and take 85 bar. Tuners have suggested that there might sometimes be a gap between the reg and body due to a thicker seal being used. Also that sometimes the reg can be moved downwards so there is a gap between the the reg's upper surface and the part of the action the barrel sits in, which may aid in reducing POI shift due to it being tightened down in an i'll fitting stock.

    Some people polish bits, some don't. What I would say is that you want to make sure all is oil free and clean when reassembled.

    Below is a pic of the different types of valve stem I've come across

    [​IMG]

    The conical V shaped stem seems to accompany the green seal and mk1 regs. There's debate as to if keeping this but just changing the seal cures the seal's issue, or if it needs replacing with the later flat type stem (right). The two also allegedly use a different spring. I can't tell the difference, the earlier springs seem to be of a different colour, but I don't have the tools to measure the spring rate. I play safe and just fit a flat valve, new spring and one of Nick's seals, and that seems to cure the problems that i've found with other seals. The parts are cheap so you may want to order a few spares should you want to change them.

    If anyone has any comments/feedback or spots an error, point it out below and we'll move on.

    I'll do the hammer next.
     

    Attached Files:

  2. Ceathreamhnan

    Ceathreamhnan WHFTA Champion 2013

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    Thanks for doing that Rob, great stuff.
     
  3. sven

    sven Member

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    Great initiative Rob. I don't think Walther is going to make the nice youtube movies that Steyr has done. So this thread with the pictures will help a lot of Walther shooters.

    I'm curious about the changes that Nick Murphy does to the pressure regulator internals. Any chance you could open up one of your regulators and picture them (the high pressure side, where the cilinder screws onto) ? I have read Nick changes the valve seal and the shape and guiding of the poppet valve in the regulator. Knowing the reg pressure setting would also be of interest.

    As Walther is not producing the LG300 Dominator anymore there might be more interest in converting existing LG300 5,5 fpe/10 meter rifles to 12fpe. The new type regulator can easily be set to 85 or 90 bar with a reg tester. This allows for 12 fpe without further modifications or new parts (except for the cocking handle). This makes conversions cheap. But to get a really good shooting field target rifle it seems some more modding to the reg is needed. But i'm not sure what it would have to look like.

    I recently converted a LG300 and a LG200 to 12 fpe for field target use and now I've got another clubmate asking me to do one for him. Would be nice to do it in such a way it creates a good shooting FT rifle right from the start. Hence the question about the mods on the regulator.
     
  4. ascoughc

    ascoughc Member

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    thanks rob for the guide, it would appear I have the black seal with a mk2 reg and cone shaped valve, I wont touch the seal, but take the hammer out and clean it first, hopefully this will sort it. I have plenty of time to do this as im using an ev2 this winter league.
     
  5. RobF

    RobF Administrator Staff Member

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    The Hammer

    Ok, this bit is a step beyond just undoing bolts. Again, take the same precautions, empty breech, no cylinder and stick her on test.

    Some of the things I do here may be done better or differently by others, but they work for me.

    What you need is;

    A decent set of drifts for the pins (no allen keys wont do)

    A magnetised set of tweezers or thin blade

    4mm allen key

    Ok, so first off, lets look at what needs to be removed...

    [​IMG]

    Each of these needs drifting out. The one on the left is for the trigger sear (don't do it yet before reading the next bit), the one in the middle is for the hammer (again, don't do it yet before reading the next bit) and the one on the right is for the hammer adjustment. It's plastic and just stops it moving loose.

    What you will notice is on the rail I have a block, with an elastic band. This allows the hammer to be pulled back and it's pin to align with the central hole. If you look at it and move the cocking handle you can just see the pin inside the hammer. Setting a block on top so the cocking lever cant fly back or forward saves you having to disassemble the cocking mechanism, which is a fiddly to put back together.

    Below is the hole to look through to see the hammer pin (which you can see in the cocking slide the other side)

    [​IMG]

    Before you get all excited, you need to drift the sear pin out first. The sear itself is nestled between two very thin washers. Get a little pot to put bits in now, and don't do this over something where you can lose them.

    Here you can see them below.

    [​IMG]

    Ok, so now you know what bits will come out, you can drift out all 3 pins. Do it with decent tools. If you don't have them then don't bother. The first few strips these will take force to get out. After that they will be easier.

    You should now have an action and these bits...

    [​IMG]

    The black pin is the one from the hammer adjustment. The longer metal one is the sear pin. The shorter one is the hammer pin. Note that 1/2 of it is striated. This allows that end of the pin to grip the hammer. Make sure when you put it back in these go into the hammer. If you get it the wrong way around it might sit nice and cosy, but vibration can make it fall out, which then sticks in the side of your stock, and throws the occasional shot low as it drags down the inside of your stock, before jumping back into place to get you guessing wtf went on.

    You can also see the two washers and the sear. If you're useless at remembering what went where which way around, then take some shots on your phone before you take the bits out.

    Ok, so now we can get the hammer out. Simply go to the back of the gun, and stick a 4mm allen key into the allen bolt and undo. It won't spring out. If your hammer is gunky or gritty it's quite normal for it to remain in the gun. Use something soft like a match stick or toothpick into the hammer channel where the sear came from and you can persuade it out with ease. You should now have these bits as well.

    [​IMG]

    On the left is the hammer. Next is the spring. Next is the spring guide/damper? Next is the adjustment allen bolt. I've put arrows on the running surfaces of the hammer, which I normally give a polish. But I leave the other surfaces alone. I degrease all these bits, and clean out the hammer bore as well. When putting the hammer in I hold the action barrel down and drop the hammer in. It should (in my opinion) bounce off the knock open spring without sticking. I then put my hand over the hole it went in and turn it upside down and check it drops back out cleanly. Assuming it does it's reassembly time.

    Hammer goes in, and I stick a pin through it into the action so it lines up with the hole. Again you can use something like a match stick or tooth pick to rotate the hammer so the hole lines up. I then drift the pin back in, making sure that the cocking slide is in the right place so the pin goes into it. When you think it's done check the hammer still moves cleanly back and forth of it's own accord under gravity. Then in goes the spring, guide/damper and bolt lightly done up. Stick the hammer adjustment pin in as well while you're here. I don't use any lube at all.

    Next is the real fiddly bit... standby for toys out of pram and patience of saint required, or if you're lucky you'll do it first time. Or the 20th.

    I use a drift to place the sear into the right place without the washers. This allows it to be easily aligned and pushed out the way as the pin is pushed back in.

    [​IMG]

    I then use a magnetised pick to dangle the first washer into place, then I gently tap in the sear pin so it goes through the first washer and the sear, but not all the way through. Then I withdraw the drift and lower in the second washer into the correct place (use the first washer as a visual guide to where it needs to go), and tap the pin all the way through.

    Don't be tempted to skimp on the washers, the sear needs to run parallel and without one or two it won't and will bind the trigger. Also, the washers can drop lower than they need to be preventing the sear pin going through. It's easier to turn the action over, let them drop out and start again.

    With them back in, it's done. Check the hammer cocks and fires ok. Sometimes the hammer pin isn't quite deep enough in the cocking slot, and this can jump off... but apart from that, there's not much I can think of.
     

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  6. blackscale

    blackscale Member

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    Thanks Rob, invaluable :D
     
  7. sven

    sven Member

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    Trigger sear and washers

    Thanks Rob, this thread gets better and better. The trick with the block on the scope rail and rubber bands to keep the cocking handle in place is a very nice one. Saves a lot of fiddling with the cocking assembly.

    My way of replacing the trigger sear and the 2 washers is somewhat different.
    I found it easier to get the sear and washers back in when I place the receiver/breechblock flat on its left hand side on the working surface. This way the sear and washers do not fall down into the block during the assembly but just lie in their position. I use an oily cloth to put a tiny bit of a light lubricating and rust protective oil (BreakFree CLP) on the washers which sticks them in place even better. And this prevents them from getting rusty from outdoor use. In fact I do this with al the black steel screws, washers, bolts on the rifle.

    This worked for me when assembling the trigger sear:
    • Put the receiverblock on its left hand side, trigger facing you.
    • Lubricate the bottom washer with a oily cloth and put it in position on the hole in the block.
    • Put the sear in place (the Walther parts drawing shows which way should be up/down, in case you forgot to take a picture).
    • Lubricate the top washer with a oily cloth and put it in place on top of the sear
    • Insert a thin (1,5 or 2mm) hex key through the hole in the top to line up the holes in the washers and sear with the holes in the block.
    • Take the hex key out .
    • Lubricate the pin and insert from the top.
     
  8. BruceGill

    BruceGill New Member

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    Thanks for this thread Rob! Just what I need :)

    Looking at my action I have a washer missing on the sear. Would Delrin be ok? Or brass? Guess I could machine a steel one too.... Thinking Delrin would be smoother
     
  9. hmangphilly

    hmangphilly Not quite a full phil

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    3mm id
    5.87mm od
    0.48mm thick

    od not too critical
    give us a shout if youre stuck bruce
     
  10. BruceGill

    BruceGill New Member

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    Many thanks mate! Made some up of delrin, so will see how the hold up. Thanks for the info :)

    Now I just need to order some hammer pins. My actions been modded to have roller bearings on the cocking linkage. The probe uses a hammer pin. Not sure how long it'll last as the one I pulled out was bent, but all working great now. Just need some as spares.
     
  11. hmangphilly

    hmangphilly Not quite a full phil

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    got some rollers here 15.8 x3 they're perfect got a few spare if you want.
    you'll just have to knock up a collar
    be careful of that other one .
    I heard they can break , and you might end up with the probe shooting back and whacking you in the facehttp://www.shooting-the-breeze.com/forums/picture.php?albumid=452&pictureid=3896
     
  12. hmangphilly

    hmangphilly Not quite a full phil

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    got some rollers here 15.8 x3 they're perfect got a few spare if you want.
    you'll just have to knock up a collar
    be careful of that other one .
    I heard they can break , and you might end up with the probe shooting back and whacking you in the face
    [​IMG]
     
  13. hmangphilly

    hmangphilly Not quite a full phil

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    got some rollers here 15.8 x3 they're perfect got a few spare if you want.
    you'll just have to knock up a collar
    be careful of that other one .
    I heard they can break , and you might end up with the probe shooting back and whacking you in the face
    [​IMG]

    that collar looks really wonky in the pic but it must be an optical thing it is straight any way you get the idea
     
    Last edited: Jun 7, 2014
  14. BruceGill

    BruceGill New Member

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    Many thanks mate! I should have a couple being sent to me by another kind fella on here :)
    Much appreciated!

    Atvb
    Bruce
     
  15. Steel Sniper

    Steel Sniper New Member

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    I have a MKII reg but the green washer and conical stem. Where is the best place to get a new washer, stem and spring?

    Andy
     
  16. hmangphilly

    hmangphilly Not quite a full phil

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    Nsra shop . Lord Roberts centre Bisley .
    Or
    A kind soul on here who might have them in his parts bin .
    I've got valve deffo if you're stuck and desperate , maybe a spring .
    The seal you get from walther is a softish ptfe material , it's fine but compresses quite quickly many shooters use a harder seal made of delrin or similar .
    Can help there if you need .
    Try nsra for bits first see what they say
    Edit :
    as per the parts diagram in this section :

    2620847----valve
    2732505----seat
    2163900----spring
     
    Last edited: May 11, 2015
  17. Steel Sniper

    Steel Sniper New Member

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    Thanks,

    I have emailed the NSRA shop, lets hope they have the bits:)
     
  18. Lavant_Lad

    Lavant_Lad Old Git.

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    You could also try www. proteksupplies.co.uk as they stock Walther LG 300 spares. Good luck in your search.
     
    Last edited: May 16, 2015
  19. rogb

    rogb Señor Member

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  20. Steel Sniper

    Steel Sniper New Member

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    I also emailed Judith. Walther are no longer mass producing the washer and now want 28 euros each! Luckily the NSRA shop had some for far less ;-)

    Thanks for all the help.
     

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