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Air Gun Home Forum Index » Rifles » Umarex AirMagnum 850-Walther 1250 Dominator mods Goto page Previous  1, 2, 3, 4  Next
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PostPosted: Wed Jul 25, 2007 3:35 pm Reply with quote
StevieLaner7777
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Hi AirGunEric

As Al said, Yes I am also using photobucket to host all my Images on here from the 14/7/07 onwards.

I also had something else to say on this subject in question, but I forgot what it was Shrug Sorry!!


Stevie Thumb Up!

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PostPosted: Wed Jul 25, 2007 6:41 pm Reply with quote
dbarr
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Thank you for the welcome!

Ok, here it goes.

First 850 AirMagnum mod and its adapter. The tank is a Catalina Cylinders 9010, 3000 psi, 1.5 cu ft tank. It is used by PepperBall Technologies, Inc. (http://www.pepperball.com/) in their PA-HPA-13 tank/regulator combination. They were helpful, but you can't purchase the tank by itself from them. The regulator is a Smart Parts Max Flow Inline adjustable that I picked up on eBay.






Current 850 AirMagnum mod. You can see there is no mount to hold the ASA to the barrel yet. The tank is an SSI (http://www.spareair.com/) 3000 psi, 1.7 cu ft tank. The tank by itself can be purchased from them for $140, but I found one on eBay. The regulator is a Nitro Duck XStream adjustable. The ASA is a System X Slider, but I will probably use a different ASA. The forearm cover will be modified to fit and cover the regulator and ASA.




Adapter used with the current conversion. This is a custom adapter made of 416 stainless steel with an 1800 psi burst disk and male quick disconnect. This adapter is hidden inside the forearm in the picture of the rifle.




The AirMagnum with its stock removed. You can see how the valve screws into the action.




The valve. Here are some valve pictures - they aren't the best (my camera isn't good at closeups), but they're something Wink . Complete valve, inside view of valve, valve seat (screws into the valve body) and valve guts (stem, face, guide, spring). The seat is actually two pieces. The larger piece has the threads to screw into the valve body, and the o-ring pops on around the air outlet. The smaller piece slips over the outside of the o-ring to hold it in place.






When I took the valve apart, there was a white substance (like Elmer's glue) on the threads. I didn't have any success with blue thread locker (I tried both regular and gel) making an airtight seal between the valve seat and body, so I tried Carpenter's glue (wood glue). It seems to work! I used Carpenter's glue instead of white glue because I read that it retains more elasticity when dry.

Drawings I made to plan how everything would fit together. Note that all the 1/8 NPT fittings are paintball fittings designed to take the high pressure.






Let me know if you have suggestions or questions.

Thanks,
DB


Last edited by dbarr on Wed Aug 01, 2007 2:15 pm; edited 4 times in total
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PostPosted: Wed Jul 25, 2007 8:09 pm Reply with quote
AirGunEric
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Aha! Now I'm getting it- the AirMagnum valve is connected directly to the gas source- I hadn't thought about that too much even with the language debate in the other AM 850 thread!

Those pictures are pretty good- certainly better than the junk my old digital camera can take.

Also DB, if you use imageshack for your images- the links it provided had a thumbnail extension on the link location. For example, "xxxx://img267.imageshack.us/img267/2903/1st850pcpys6.th.jpg" if you remove the ".th" before the ".jpg" extension it links to the full-size picture. Not sure why their system does this- but it seems to be quite laborous just to get the image posted. Anyways- I eliminated that extension so your pics are normal.

Nice work- I am a bit surprised that removing the pin, filter and polishing the valvebody gained nearly 100fps because of this- that seems ridiculously high. Obviously the valve design was a bit "lacking" from the factory! Good to see someone pull it apart and analyze the result. Did you happen to try it with the piercing pin still there and a polishing with only the screen removed, for those people that want to retain the ability to use the AirSource canister?

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PostPosted: Wed Jul 25, 2007 9:56 pm Reply with quote
dbarr
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Thanks for the info Smile .

Note that 594fps was at 800PSI while 685fps is at 1000PSI! So not only were the puncture pin and filter screen removed, but the pressure was increased. Before I removed the puncture pin and screen, 1050PSI sent a slightly lighter pellet at 619fps.

Sorry, I didn't do any tests with just the screen removed. I wanted to open the valve only once if possible. I will eventually test at 800PSI again to determine exactly how much gain the changes gave me.

I used a DIY chronograph for my testing - see http://www.seattleairsoft.com/modules/news/article.php?storyid=15&page=0.

There is some info on Pyramyd Air's blog at http://www.pyramydair.com/blog/2006/06/rws-850-airmagnum-part-2.html. I am ".22 multi-shot" there.

DB


Last edited by dbarr on Thu Jul 26, 2007 2:01 am; edited 3 times in total
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PostPosted: Thu Jul 26, 2007 12:53 am Reply with quote
broommaster2000
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The first conversion is a bit to much of a rig to my taste. The second one too, but it has potential to fit in the stock, if you would cut a hole in the front of the removable part.

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PostPosted: Thu Jul 26, 2007 1:22 am Reply with quote
dbarr
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I agree, I didn't like the look of the first conversion Crying or Very sad !

I designed the second so that it can be hidden by the stock cap with some hole cutting and other shaping. I will do that after I finalize which regulator and ASA to use. Then all you will see is the tank, gauges and fill connector sticking out (which I hope will look natural for a PCP).
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PostPosted: Thu Jul 26, 2007 1:26 am Reply with quote
broommaster2000
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You're doing great research. I gotta hand you that. Good work. Wink

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PostPosted: Wed Aug 01, 2007 3:24 pm Reply with quote
dbarr
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I'm sure the Walther Dominator 1250 has at least a different valve and hammer spring than the 850. It might also require a heavier duty hammer. One day, when I get braver, I might open the action on my 850 to see what's inside Eek .

DB
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adapter? 
PostPosted: Wed Nov 14, 2007 9:12 pm Reply with quote
jjensen6387
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hey Db!
I was wondering were or how you aquired that second adapter if i may ask? I just purchased my AM850 in .177 its a sweet gun!

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PostPosted: Thu Nov 15, 2007 4:26 pm Reply with quote
dbarr
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No problem. I assume you mean the stainless steel adapter. It is a custom adapter that I made. It is made out of a piece of 5/8" diameter, stainless steel round bar. The metal stock was T-416 round bar stainless steel from www.onlinemetals.com.

The easiest thing to do is buy an AS to PB adapter from Mac1 http://www.mac1airgun.com/ for $25. It is made out of type II black anodized 6061 T6 aluminum. The Mac1 adapter is too long for my conversion. It has a standard paintball ASA (a paintball tank will screw directly into this) on the side opposite the AirSource thread. To adapt the paintball ASA to a quick disconnect you need to buy another adapter (C/A to 1/8 Inch NPT Adapter & Quick Disconnect Kit - Nickel / Steel). I got these at www.actionvillage.com under the "Hoses and Parts" section.

The only other commercial AS to PB adapter I know of is from Cooper-T. It is part# 5606 at http://www.cooper-t.com/bottlestoppers.html It has a slide check as well as being an adapter. I don't know how long these will be available. It is my understanding that he died and someone is selling the remainder of the stock for the family. I have this adapter, it is the red adapter shown in the pictures of my first mod. After modifying the 850 valve for better air flow, a piece of metal flew out of my Cooper-T adapter and stuck in the valve, so I don't know that this is the best adapter to use at higher pressures (I had my regulator set to probably around 1000 PSI when this happened).

The custom adapter I built is threaded with an M16x1.5 (16mm diameter, 1.5mm pitch) die on the AirSource side. The smooth part before the thread is 1/4" long and .508" in diameter (an o-ring seals on this smooth section). The quick disconnect is a part that I bought from Action Village. It is screwed into a 1/8 NPT thread drilled and tapped into the end of the adapter. Red threadlocker was applied before screwing in the quick disconnect. There is a 1/8" hole drilled completely through the adapter.

The tools I used to make the adapter were: 6" digital caliper, drill press, 2" lathe chuck, flat file, sand paper, titanium nitride coated drill bit set, M16x1.5 die, die stock for 1 1/2" dies, 1/8 NPT tap and a belt/disc sander.

The die and die stock I bought at Victor Machinery Exchange (www.victornet.com).

The lathe chuck came from Harbor Freight, but they don't always carry it. Grizzly Industrial (www.grizzly.com) carries one like it, the H5934, but it is more expensive and comes with Morse Taper #1 and #2 arbors. The one I bought only came with a Morse Taper #2 arbor. You can also find these lathe chucks on eBay. Hopefully you have a drill press that takes a Morse Taper #1 or #2 chuck arbor otherwise you have to make your own. Or I'll sell you my 2" lathe chuck with the 12mm arbor I made - the 12mm arbor fit into my regular drill chuck like a drill bit. I don't need the lathe chuck anymore since I have a lathe now.

I gave up on the adapter pictured here because its diameter doesn't allow a long enough thread section for the burst disk threads to seal. I took this adapter, cut off the M16x1.5 section, threaded the back end and screwed it into a modified Palmer's Pursuit Shop adapter to make my final adapter.

I am planning to blog my 850 conversion at some point, but don't hold your breath. I started this project last September!

DB
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PostPosted: Sat Nov 17, 2007 2:53 am Reply with quote
JGTC-spec
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The Cooper-T adapter is hard to get now since the owner passed away. These are the current 2 options.

http://www.network54.com/Forum/583224/message/1194375452/MAC1+Adapter+Fix+by+Tom

http://www.network54.com/Forum/583200/message/1194903368/Hello+folks%2C+this+is+my+850
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PostPosted: Sat Nov 17, 2007 8:21 am Reply with quote
AirGunEric
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Has anyone actually gotten anything from the Cooper-T stock since last December? Chauncey (Cooper-T) passed away in August, but hadn't been doing any business for at least 8 months before that, and despite some people claiming to have spoken to his son (Jr.) and posting a "valid" email address where people could request products- I never heard any more about it- and I know my emails to the email address provided were never answered.

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PostPosted: Sat Nov 17, 2007 11:24 am Reply with quote
JGTC-spec
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AirGunEric wrote:
Has anyone actually gotten anything from the Cooper-T stock since last December? Chauncey (Cooper-T) passed away in August, but hadn't been doing any business for at least 8 months before that, and despite some people claiming to have spoken to his son (Jr.) and posting a "valid" email address where people could request products- I never heard any more about it- and I know my emails to the email address provided were never answered.


Tim at the 850 forum is the last person I've heard that got stuff from Cooper-T after he owner passed away. He waited a long time before getting the response.

http://www.network54.com/Forum/583201/message/1191472961/Got+the+Cooper-T+Adapter+today.
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PostPosted: Fri Feb 22, 2008 4:48 pm Reply with quote
dbarr
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For anyone interested, I've started a blog on the subject of using air to power things. In it I am covering the conversion of an RWS 850 AirMagnum to PCP Smile .

DB


Last edited by dbarr on Sun Feb 24, 2008 1:50 pm; edited 1 time in total
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PostPosted: Sun Feb 24, 2008 1:49 pm Reply with quote
dbarr
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Sorry, forgot to post the URL Embarassed ! Here it is
http://airnergy.blogspot.com/

DB
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Umarex AirMagnum 850-Walther 1250 Dominator mods 
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