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Air Gun Home Forum Index » Rifles » Umarex AirMagnum 850-Walther 1250 Dominator mods Goto page 1, 2, 3, 4  Next
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Umarex AirMagnum 850-Walther 1250 Dominator mods 
PostPosted: Fri Jun 15, 2007 12:04 am Reply with quote
AirGunEric
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With the recent inquiries into the AirMagnum 850 and possible upgrades to make it more like the 1250 Dominator, I thought I should put what I could find together.

First- Umarex and Walther are the same company for airguns (they merged in 1993 in respect to airgun design/manufacturing). In the United States, the Umarex guns are typically re-labelled "RWS" who is the Umarex importing agent for them and Diana airguns.

The Umarex AirMagnum 850 looks like this:




The 850 is a Co2 powered gun using 88gr AirSource cylinders, and comes in 7.5J(5.53fpe) and 16J(11.8fpe) versions. In the US the 7.5J/5.53fpe version retails for approximately $250 USD.


The Walther 1250 Dominator looks like this:




The 1250 Dominator is a PCP gun, and comes in versions with power outputs of 7.5J (5.53fpe), 16J (11.8fpe), 28J (20.65fpe) and 40J (29.5fpe) in the .177 caliber format. According to all available documentation I could find, it is based on the Walther LG300 Dominator platform (i.e. internals) which came in 16J (11.8fpe) and 21J (15.49fpe) versions and was designed for Field Target Competition use (and carried a $2500.00 USD list price- it has now been replaced by the 1250 Dominator FT).

Picture of the LG300 Dominator:




And it's replacement, the 1250 Dominator FT:




So- seeing as how I can't find any parts or service information on any of these guns (obviously Umarex/Walther keeps this close to the vest)- I must go with the theory that if the LG300 and 1250 Dominators are of the same internal design- at least some of these features must be incorporated into the AirMagnum 850.

Here is an optional filling kit for the LG300 Dominator:

Pic:




url:


LG300 Fill Kit Link


I have no idea why I had to find that through the Amazon affiliate vendor system- but the search function on PyramydAir sucks so bad I had no other choice!


So- if one wanted to upgrade an Airmagnum 850- the easiest path would be if one had a 7.5J/5.53fpe version to order the 16J/11.8fpe valve assembly and swap it in. If this isn't enough power or someone wants to convert it to PCP- the most obvious path appears to either purhase a fill tube kit like the one above, and install the valve/regulator setup from a 1250 Dominator 28J/20.65fpe or 40J/29.5fpe guns. If it proves that the valves are not available to be purchased- then it appears one could take a 16J/11.8fpe valved AirMagnum, use the fill kit and push maybe 1300psi through the Co2 valve- giving it somewhere in the ballpark of 22J/16fpe. Beyond that pressure, as with virtually all Co2 valves- it likely wouldn't open allowing discharge and/or would end up blowing out the seals.

Now- what needs to be done to connect the filling tube to an AirMagnum's 88gram AS port? Either a custom adapter, which would extend the fill tube out from the gun an inch or two further than on a 1250 Dominator, or finding the correct parts from Walther that were designed for the 1250 Dominator.

As Broommaster had mentioned in his main post on the AirMagnum 850- perhaps just finding a way of refilling the 88gram AS cartridges- possibly with air at around 1000psi would be the simplest and cheapest thing to do.

However, before trying this- someone needs to hydrotest an AS cartridge- which despite this topic having come up again and again- somehow no one seems to have actually done the testing.

As an example of re-filling an 88g cartridge, here is a picture of a pin-valve screwed into an AS cartridge (i.e. a Shrader valve). The one on the right (not attached to the refill tank) is only about 1/8" longer with the modification than a standard Crosman 88g cartridge and retains about 80% of the threads to screw into the gun. The gentleman who did this was "JimC" on another forum- but I can't remember which one now (dang!):




Sorry I can't offer any more insight right now- seems to be a real scarcity of info on these guns in respect to modding/conversion. As/when I find things I will post more.

If anyone finds more- please post it here as well. If you decide to be the "first" we're aware of doing a PCP conversion to the AirMagnum- please detail it and post pictures!

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PostPosted: Fri Jun 15, 2007 10:24 am Reply with quote
boeing299
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many thanks eric Cool
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PostPosted: Wed Jun 20, 2007 4:00 am Reply with quote
AirGunEric
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OK- I managed to locate a diagram for the LG300 guts- just none for the 1250 or AirMagnum 850 (yet):

http://www.airgunhome.com/forumdocs/lg300dominatorparts.pdf


Unfortunately- the text is in German- but I got out the dictionary to get down to business!

If you look at the diagram- part numbers 62 (pressure tube), 35 (pressure spring), and 51 (pressure regulator) are different than what would be found on the Umarex AirMagnum 850- other, more minor parts would also be different- the most expensive of the bunch would probably be the forearm for the stock.

So- we can see a pressure tube kit like from PyramydAir is $190 USD, then throw in the parts mentioned above, plus the minor ones, and we can easily add another $200 USD to this, then there's the cost of the 850 itself- so we're at $615 +++ to get the AM850 more like a Dominator 1250. The 850 retails at around $225-275, the 1250 Dominator I haven't got a "street" price on, but it lists for 499, or about $670 USD- so 'street' price is likely in the $600 range.

Does anyone really want to take an AM850, buy a boatload of parts, be into it for a minimum of $600 when they can just go a buy a 1250 for $600 in the first place? Seems counterproductive unless someone already has an 850 they are tired with, or that they didn't pay anything to acquire.

That refillable AS cartridge idea using air at 1200psi definitely seems to be the most economical and simplest mod that can be done to the 850 for (somewhat) higher power output.

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PostPosted: Wed Jun 20, 2007 8:49 am Reply with quote
broommaster2000
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I think that there are major differences between the LG300 and the AM850. From what I can see, it's hardly comparable.

The LG300 seems to be a single breech loading airgun. The 850 is anything BUT that.

Better check out the price difference in Crosman Airsources compared to refillable airsources. That would make things a lot easyer, and it's a lot cheaper I bet.

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PostPosted: Wed Jun 20, 2007 12:49 pm Reply with quote
AirGunEric
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broommaster2000 wrote:
The LG300 seems to be a single breech loading airgun. The 850 is anything BUT that.


The LG300 is, as far as I know, a single shot load system. However, the Dominator 1250 is an 8-shot magazine load and the two share the same powerplant. Look at the LG300 diagram- the loading system is missing- only the actual powerplant seems to be depicted. What the layout on the internals of the 850 is, I can't say specifically- if you could show us pictures of yours that would help greatly.

broommaster2000 wrote:
Better check out the price difference in Crosman Airsources compared to refillable airsources. That would make things a lot easyer, and it's a lot cheaper I bet.


Have any links to specific manufacturers of refillable AS units? That would be helpful as well.

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PostPosted: Thu Jun 21, 2007 11:43 am Reply with quote
broommaster2000
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Can't help you with manufacturers, but if you visit a paintball-club, they can help you on the way.

Paintball is a lot further in refilling CO2-bottles. They can probably help you.

My plan is to buy a used (but approved) CO2 Fire-extinguisher. I will also have to buy some different parts like special ventiles. I haven't asked anyone about it yet, but I will ask around soon when I got time.

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PostPosted: Thu Jul 12, 2007 8:30 am Reply with quote
AirGunEric
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Update (of sorts):

A month ago I sent Umarex's head office a request for parts diagrams/breakdowns of both the AirMagnum 850 and the Dominator 1250. After a week, the Vice-President of International Sales responded stating that neither were currently available.

So, I asked "when might they be available."

The response- 3 weeks later(!) from Mr. VP's assistant/secretary was:

"Dear Sir,

Thank you for your mail! However, these exploded views will also not be available in future.

Best regards.
ppa. Eyck Pflaumer
Vice President International Sales

Donnerfeld 2
59757 Arnsberg
Germany
Tel: +49-2932-638-241
Fax: +49-2932-638-249

www.umarex.de "



This is not to say there are no diagrams out there or that there never will be- these guys are a bunch of Germans, and Germans, in my experience, seem to suffer generally from some sort of compulsion to putting together paper and records on anything they can think of. That being said, obviously they have no intention of voluntarily letting the common airgunner acquire these records.
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PostPosted: Fri Jul 13, 2007 3:26 am Reply with quote
broommaster2000
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AirGunEric wrote:
Update (of sorts):

A month ago I sent Umarex's head office a request for parts diagrams/breakdowns of both the AirMagnum 850 and the Dominator 1250. After a week, the Vice-President of International Sales responded stating that neither were currently available.

So, I asked "when might they be available."

The response- 3 weeks later(!) from Mr. VP's assistant/secretary was:

"Dear Sir,

Thank you for your mail! However, these exploded views will also not be available in future.

Best regards.
ppa. Eyck Pflaumer
Vice President International Sales

Donnerfeld 2
59757 Arnsberg
Germany
Tel: +49-2932-638-241
Fax: +49-2932-638-249

www.umarex.de "



This is not to say there are no diagrams out there or that there never will be- these guys are a bunch of Germans, and Germans, in my experience, seem to suffer generally from some sort of compulsion to putting together paper and records on anything they can think of. That being said, obviously they have no intention of voluntarily letting the common airgunner acquire these records.


A generalization. "a bunch of Germans, Germans in general". Bureaucracy in general, you surely mean.

There are plenty of non-German companies that won't help you out. It's bureaucracy, and I know plenty of Germans that don't work like that. If you complain about anyone, complain about the company. I don't think it's got to do with them being German.

It's not very nice of a company to not have part diagrams ready though. I think that you, AG-Eric, are right there. I have a Slavia, used, second handed, and when I send an email about parts they replied with different solutions. I think that's service. They didn't ask me any more questions, just replied with dealers in parts.

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PostPosted: Fri Jul 13, 2007 3:43 am Reply with quote
Alstone
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Hi all, if you want information on any equipment on the web especialy European including the UK, the best place to go is the USA, they have all the information you could want, on what they are selling, where as in europe they like to keep things a secret, then they have power over you.

On an European web sit for say a multi-national company, there is usualy not much information, where as in the USA for the same company there is all the information you could want.

AL
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PostPosted: Fri Jul 13, 2007 5:21 am Reply with quote
AirGunEric
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I'm not sure what Umarex's specific problem is/isn't. They do have diagrams out there for many of their products- so why they are withholding diagrams for these ones I have no idea (Walther's site has diagrams for the LG-300 online).

And yes, I do mean "Germans" in general. In my view, Germans have had a near-compulsion to keep records and 'paper' on things. Obviously it is Umarex being difficult here for whatever reasons- but being a German company there is absolutely no doubt in my mind the materials do exist and are probably in the possession of every representative and repair facility they work with. Why they will not release them to airgunners directly I cannot explain. Just not good "customer relations" in my view.

As Al suggested- perhaps I should contact the US-based Umarex people and see if they might be willing to release the documents. I had thought going "straight to the horse's mouth" would produce better results.

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RWS 850 AirMagnum PCP conversion 
PostPosted: Tue Jul 24, 2007 11:47 pm Reply with quote
dbarr
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I just found this thread googling for "Walther Dominator 1250". I have been watching to see what the price will be when it comes on the market.

I am currently in the process of converting my .22 AirMagnum to PCP. I am new to forums so I am not sure how to post pictures of my project.

I finished my first conversion (no mods to the gun itself), but I wasn't happy with it. I finally got brave enough, removed the valve and opened it. I removed the puncture pin, filter screen and reamed/polished the inlet and outlet. That increased the power so that JSB Exact Jumbos (15.8gr) did 660fps @ 850PSI up to 685fps @ 1000PSI. The prior version averaged 594fps @ 800PSI.

All the versions I've tried so far use a small 3000PSI tank with a paintball regulator. That combination is connected to the AirMagnum via various adapters.

The stages I have left for my current conversion are:
1) make a mount to fasten the ASA to the barrel,
2) modify the stock cap to fit over the regulator/ASA.

After that I am thinking about experimenting with different valve springs and maybe hammer springs.

DB
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PostPosted: Wed Jul 25, 2007 2:01 am Reply with quote
AirGunEric
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I'm sure everyone would like to see pictures of your project and its progress!

To post pictures you need to "size" them correctly- in the case of the airgunhome forum- it is designed for 1024x768 resolution- so a maximum width of around 700 pixels works well (I personally like 650 pixels for my own posts). If you have these pics resized (using something like Microsoft Photo Editor) you can get them hosted on a site like photopoint.com.

Or you can add them to your post by clicking on the "Add Image to post" button on the screen when you are posting a reply to something here. Using this option you upload the file to the service that holds the photo, a small box picture gets placed in your post and a button to view it full-size (along with some advertisements) is attached. The photos in my first post of this topic are done with this. Using this method- you can leave the pictures as they came out of your camera- although you may still want to re-size them to around 800-900 pixels wide so people aren't "chasing" the stretched picture all over the screen. I think the imaging host site will also only accept pictures with a maximum size of 5mb- so this will limit the size as well.

And, welcome to the site!
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PostPosted: Wed Jul 25, 2007 4:32 am Reply with quote
Alstone
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Hi Eric, I think Photopoint as gone bust, the domain is up for sale.

AL
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PostPosted: Wed Jul 25, 2007 11:43 am Reply with quote
AirGunEric
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Alstone wrote:
Hi Eric, I think Photopoint as gone bust, the domain is up for sale.

AL


Uh. Seems I'm a bit out-of-date! What service for photo hosting are you and Stevie using?

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PostPosted: Wed Jul 25, 2007 1:04 pm Reply with quote
Alstone
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Hi Eric I'm using mainly Photobucket, or Postimage if I want a clickable thumbnail on the post, I think stevie also uses Photobucket.

AL
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Umarex AirMagnum 850-Walther 1250 Dominator mods 
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