LP400 Absorber

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David M
Posts: 1641
Joined: Wed Mar 24, 2004 6:43 pm

LP400 Absorber

Post by David M »

Does anybody know the correct adjustment for the Walther LP400 Magnetic Absorber ?
Mine was blocked with muck, so stripped, cleaned and re-assembled. I adjusted it to
the release point then out one turn. It appears to now work but I am not sure if this
adjustment is correct.
David Levene
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Joined: Mon Mar 01, 2004 12:49 pm
Location: Ruislip, UK

Re: LP400 Absorber

Post by David Levene »

Blimey David, you're the guru on all gun related technicalities.

If you don't know then we're all doomed :-)
David M
Posts: 1641
Joined: Wed Mar 24, 2004 6:43 pm

Re: LP400 Absorber

Post by David M »

Feedback from the factory service tech's...

" the way you adjusted is quite good. This is almost the way we tell peaple to adjust.
In the end the absorber have to release with the shot and have to catch the masspart when loading.
Than the function is good.
To adjust the feeling to you, you can turn a bit on the screw on the left side at the backend of the pistol.
The screw just opens or close a small hole and so you regulate the airpuffer. "
Spaceball
Posts: 32
Joined: Tue Dec 18, 2012 6:39 am
Location: South Australia

Re: LP400 Absorber

Post by Spaceball »

Hi David

What indication did you get that the absorber was blocked?
With my LP400 every now and then when I take a shoot a I can feel a secondary movement for the gun. Bit hard to explain.
It there is no muzzle movement it the shot feels great. Most of the time I can not feel that so I am not sure if it is an absorber or technique issue.
Might give the absorber a clean and see if that changes anything. Did you use any sort of silicon lube in the reassembly?

Thanks

Spaceball
David M
Posts: 1641
Joined: Wed Mar 24, 2004 6:43 pm

Re: LP400 Absorber

Post by David M »

Mine became intermittent in function. Sometimes it would not release and I did get two different impact points groups.
Found the air channel of the absorber adjustment screw blocked preventing the release of the striker every time.
If you take the grip off you can see the absorber function. Be carefull it only works when a pellet is fired.
It needs the backpressure from the chamber to fire the striker release.
After cleaning and re adjusting it works fine, I also run it dry.
Silicone or grease will eventually gum it up.
northpaw
Posts: 296
Joined: Fri Dec 13, 2013 12:15 pm
Location: Nordrhein-Westfalen

Re: LP400 Absorber

Post by northpaw »

David M wrote: Mine became intermittent in function.... and I did get two different impact points groups.
Silicone or grease will eventually gum it up.
Exactly. Common problem encountered when firing well-used absorber-featuring airguns. Typically two more or less distinct subgroups. Deteriorating the scores.
An absorber introduces a new variable to the gun. No doubt about that. Pleasant when functioning properly, but with increasing use/age they not always do.
Have formerly run into similar severe problems with absorber equipped FWB APs.
Joebewon
Posts: 1
Joined: Fri Oct 24, 2014 9:24 am

Re: LP400 Absorber

Post by Joebewon »

Can you please tell,and show me how to remove, clean and adjust,the LP 400 absorber.
I'm not sure which screws do this, I've removed the grip on my Walther and am not sure,
which ones they are. An illustration or photo would help, if possible. Thank you.
Joebewon
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j-team
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Location: New Zealand

Re: LP400 Absorber

Post by j-team »

Something that can happen with the Steyr LP10 stabiliser, that may or may not happen with the walther LP400 but worth mentioning anyway.

If you pull back the cocking lever only just far enough to re-set the striker (sear) it isn't quite enough to re-set the stabiliser, that needs the lever to be puller back just a fraction further. So, it is possible to reload and fire the pistol even thought you haven't puller the lever all the way back to re-set the stabiliser.

Can this happen with the Lp400? (I'm not familiar with them).
David M
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Joined: Wed Mar 24, 2004 6:43 pm

Re: LP400 Absorber

Post by David M »

The LP400 does not have a sear to set like the Steyr LP10 stabiliser, it is a magnetic link that uses a air pulse on a striker to release.
Mine the magnet was doing its job but the air channel to the striker was blocked with muck.
therider
Posts: 456
Joined: Fri Nov 29, 2013 6:33 pm
Location: Germany

Re: LP400 Absorber

Post by therider »

j-team wrote:
If you pull back the cocking lever only just far enough to re-set the striker (sear) it isn't quite enough to re-set the stabiliser, that needs the lever to be puller back just a fraction further. So, it is possible to reload and fire the pistol even thought you haven't puller the lever all the way back to re-set the stabiliser.
Gosh... Is it really so?
How do you recognise that? Will the muzzle flip as a pistol with no recoil absorber?

Regarding the absorber of the lp10e I keep hearing a story about an inconsistent behaviour of the absorber from shot to shot due to its design. I have also heard that many profis remove the absorber!. Is it really so? Does anybody know some thing about this?
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j-team
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Location: New Zealand

Re: LP400 Absorber

Post by j-team »

therider wrote: Gosh... Is it really so?
Yes, if you pull back the lever very slowly and stop as soon as you hear the click (thats the sear engaging) it will be possible to fire without stabiliser.

But, if you just operate the lever normally, then it's OK. You really need to deliberately do it to make it happen like this. I have not fired it like that to see if it has muzzle flip, but will try when I am next at the range to see.

Edited to add: I just tried it with my wife's pistol (LP10, mine is an LP10e). On the LP10 the stabiliser re-sets just before the trigger (sear). Not sure if they are both normal for LP10 and LP10e respectively but it's interesting that they are different.
Spaceball
Posts: 32
Joined: Tue Dec 18, 2012 6:39 am
Location: South Australia

Re: LP400 Absorber

Post by Spaceball »

How do I know if the LP400 absorber is operating?
I have attached a picture (not my pistol) of the slot where I can see the absorber but it does not change position when I fire it with a pallet in the chamber.
When the absorber moves towards the rear after firing does it stay there? Or will it rebound back and connect back onto the loading plunger (sorry for all the poor terminology).
I just checked and noticed that I have two different exploded diagrams. An earlier one that shows all the individual parts of the absorber valve and one that shows the absorber as a complete assembly. Based on what it looked like when I dissembled it I have the later one.
I tried the adjustment screw #197 1 turn in and 2 turns out from factory with still no absorber movement.
How do I test that the valve is letting the air through to release the absorber?
Can the valve on the later ones be disassembled or adjusted?
When I reassembled the absorber I left the magnetic piston is the "fired" position. When I cocked the pistol you can hear a two distinctive clicks, one of the sear and one of the magnet jumping back onto the loading plunger. If this is the standard operation for the magnetic to stay back and get picked up when cocked then I do not think I have ever heard this second click before, or it was a long time ago.

Also be warned if you attempt to pull that later model absorbers out there are two plastic balls in the side of the absorber piston (#183 on the exploded view). These are under spring pressure and they WILL go flying when the piston is removed. Do this in a plastic bag and save the time on you hands and knees looking for them on the floor.
Attachments
Absorber.jpg
David M
Posts: 1641
Joined: Wed Mar 24, 2004 6:43 pm

Re: LP400 Absorber

Post by David M »

I have the early Absorber so I refer to these numbers.
Absorber LP400.jpg
When fired the Absorber weight 117 is in the rear position and the spring is visible.
As you cock the pistol the Slide Tappet 118 is moved aft, compressing the spring
until it is close to the Absorber Weight 117.
When close the magnets attract and connect. This is one of the clicks you hear, the
other is the trigger setting.
When the breech is closed the Absorber weight moves forward with the Tappet, this is the
cocked position as shown in your photo.
When fired the air pulse travels thru the Adjusting screw 119 and impinges on the Trigger 120
to push apart the magnetic faces, releasing the absorber weight and the springs push it aft.
To adjust Screw 119, cock the Absorber then slowly turn 119 in until the magnetic faces release.
Then turn the screw out 1/2 to 1 turn (adjust for feel).
To achieve the required backpressure to fire you need to fire a pellet in the chamber. BE CAREFUL use
all normal safety as you live fire test the pistol.
Spaceball
Posts: 32
Joined: Tue Dec 18, 2012 6:39 am
Location: South Australia

Re: LP400 Absorber

Post by Spaceball »

Thanks David

based on the information that you have supplied my absorber is not working. I doubt that it has every work constantly. Maybe 1 in 100 shoots.
The attached picture is how my model absorber is shown in the exploded diagram. When disassembled my Slide Tappet looks as if it has been pressed together. Not sure if it is serviceable. Part 183 are the little plastic balls that go flying if you are not careful.
I will pull it a part again at a later date and add some photos.
Anyone else have any suggestions?
Attachments
Absorber parts.jpg
Absorber parts.jpg (42.38 KiB) Viewed 2633 times
Spaceball
Posts: 32
Joined: Tue Dec 18, 2012 6:39 am
Location: South Australia

Re: LP400 Absorber

Post by Spaceball »

Shot a bit of a practice match tonight. Out of 60 shots I did not feel the absorber activate and visually check nearly every shot and it was still in the forward position connected to the Tappet. After 30 shots I unscrewed the bleed screw in the frame at the back of the absorber channel to see if it made a difference. Only backed it out two turns and no difference.
Here are some photos of the inside of the newer absorber.
From what I can see the Tappet can't be disassembled.
Attachments
Absorber tappet back.jpg
Absorber mag tappet.jpg
jbshooter
Posts: 364
Joined: Sun Dec 02, 2007 12:39 am

Re: LP400 Absorber

Post by jbshooter »

The serial number on my LP400 is 72005. Is that the older or newer version?
Spaceball
Posts: 32
Joined: Tue Dec 18, 2012 6:39 am
Location: South Australia

Re: LP400 Absorber

Post by Spaceball »

Mine is 732XX.
David M
Posts: 1641
Joined: Wed Mar 24, 2004 6:43 pm

Re: LP400 Absorber

Post by David M »

OK, I give in....how does the new version function ?
Does it use direct air impingment to release the magnet ?
Spaceball
Posts: 32
Joined: Tue Dec 18, 2012 6:39 am
Location: South Australia

Re: LP400 Absorber

Post by Spaceball »

Love to get it apart or even see the CAD model to see how it works.
I can't see how the air can act directly on the magnet. There are two closed holes at which can be see in the picture that the magnet sits over. For air to get this far down the Tappet it has to pass through the larger mid section where the cocking leaver mounts. There are two holes which are 90 degrees apart from the cocking lever holes and they pass through the center so any air would be vented through these. You can also see a very heavy spring that runs through the middle of the Tappet.
My theory is that air enters the front of the tappet and acts on a piston that is held closed by the heavy spring above. This piston actions on another magnet in the rear of that Tappet (you can feel the magnet in there with the larger magnet removed). This disturbs the magnetic forces between the Tappet and the magnetic weight and the weights shoots to the rear. The two little spring loaded plastic balls are used as a damper system. Just a theory.
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