Walter's AA 400 Regulator

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Walter's AA 400 Regulator

Post by Mac » Fri Nov 22, 2013 2:33 pm

Although I have had the reg for some time, I finally used the S410 Carbine a match this past October. I have to apologize to Walter for not getting to it sooner, but I am quite sure Walter knows how busy life can be.

I had some specific goals in mind and Walter was able to achieve them all. I had a length in mind that would allow me to still use the barrel band and that was achieved. I wanted the reg pressure set for a certain pressure, but also wanted some adjustability. That was done. I wanted it to be a simple install and be vented and that was worked in as well.

Below is the only change I had to make. I had to shorten the brass firing pot to fit inside the low pressure end of the regulator. Replacing this part to go back to stock arrangement is very simple.

Firing pot and valve body

The pressure tube was removed from the gun and the pot was taken out after loosening the locking grub screw. The end was then taken off to shorten it enough to fit. I had counted the revolutions to take the pot off and screwed it back on to the same depth, since this is what sets the valve spring tension. The smaller low pressure area inside the reg serves the same purpose as the long end of the firing pot, so the firing characteristics of the gun are the same.

Low pressure side of reg

High pressure side of reg

I then installed the regulator by simply screwing it on the thread where the pressure tube had been. See top pic above. At this point is where one of Walters innovations really showed its worth. On the high pressure end where the reg pressure adjuster would normally be a screw of some kind, Walter put something much more useful and clever. He shaped the adjuster in the form of a male foster connector, which allowed me to attach the scuba tank to it and check the reg pressure without installing the pressure tube and filling it. You can see in the pic that Walter marked the face of the reg and the foster and the dots line up at the pressure I had requested. So I attached the scuba tank up that had just under 200 bar in it and pressured up the reg. The needle on the tank read the high pressure and the gauge on the gun showed the regulated pressure which sat very near 100 bar. I was able to shoot some shots over the chrony just to be sure and with the marks aligned it was putting out about 11.7 fpe. Perfect. I shut the tank off, depressurized the fill hose and removed it from the reg. I shot the gun once to depressurize the regulator and was then ready to put the main pressure tube on. I made sure the tube was dust free and installed it on the high pressure end of the regulator. After installing the barrel band over the tube end and barrel, I was ready to give it a go.

I filled the gun up to 200 bar and started shooting over the chrony. Even with the shorter tube, I was able to get 65+ regulated shots with less than 10 fps spread. Good to go.

Flash ahead a number of months and I actually did get it out to the Fudd match. I installed the 6500, 2.5-16 scope and did a little shooting to determine the points of hold for the various distances. I made up a chart for the mil dots and was set to go. The chart was great and except for a few standing shots and some early unsteadiness, I was doing well and only down five points at the half way mark. Great! I started the second half mowing the targets down and then started missing, six shots in two lanes. I felt good, so figured something had gone wrong. I gave the gun a once over to see if it was something easy. As it turned out it was pretty easy and something I should have been checking at the start of every lane. In the handling of the gun, the elevation on the scope was ten clicks off. Probably had you wondering if the reg had gone south. I put the scope back to zero and didn't the targets start falling again. So the gun and reg functioned flawlessly, but he part between my ears had a bit of a lapse.

I am very pleased with the regulator and the consistency it brings to the velocity. I know some of the higher power AA 400 series guns have a curve with a sweet spot between 150 and 100 bar. This reg will allow you to fill right up to 200 bar and you get the extra shots from the extra 50 bar that can now be used.

Thanks and congratulations to Walter for a job well done. Sorry it took so long, but thats the story of the WG Regulator for the AA 400 series guns.
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Re: Walter's AA 400 Regulator

Post by blade57 » Mon Nov 25, 2013 12:38 am

Great write-up Tim.

My Ripley AR5s has one of Walters regulators fitted as does my Hatsan. AT-44. The man is an artist for sure. Love his work :D

DaveD :D

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