Opening AT44/Pneuma air cylinder

[Stefan]

My regulator came in today (http://www.altaros.cz/).
Its simple install, no need to drill any holes, just drop it in.
I just don't know how to open the air cylinder, without damaging it? From what I have read they open really hard. Any tip on how to do it?
Of course, it will be degassed.
After installation, I shall shoot some strings for reference. Its preset at 125 bar, and I can get it up to 130, or down to 110.




and maybe some info on how to install this? after reading the Ondrejs description, it wasn't much more clear to me (mixed English Czech...)

[Ribbonstone]

Bought mine used, but the previous owner did what i had planned to do.  Filed two small flats (see pix below) between the ports and the threads.  Used an an adjustable parallel jawed wrench. (but for goodness sake..be sure it is EMPTY OF PRESSURE!)


Probablyt want to get a strap wrench to go around the air tube (can find them at Harbor Freight for a few $) to keep from marking that up.

Have never seen that regulator, and have no diea how to install it...sorry, maybe some close ups would give me an idea.

[Stefan]

OK, I I've done it. Got my cylinder regulated to 125 bar.
You need 13 mm wrench, and a friend that has bench vise . We used some kind of leather to save the surface of the cylinder, when inserted into the vise. Just light taps with the hammer on the wrench got it loose enough, to be unscrewed by hand. Then we inserted the regulator in the tube, the top part in the picture first, then screwed back in the valve body. And that was it.
Then I tried to hand pump the cylinder. No luck. It was leaking air through the valve. Googled it, but I didn't find the solution how to do it. Then, on YT, i saw some Spanish dude video on hatsan regulator, and somehow I I've figured out that I need to pump the cylinder back to 50 bar, to stop the leak, and that I had to use that degassing part that came along with at44 to stop it leaking while i get to 50 bar (Teflon tape helped me out, to seal those two holes on degass-er, I used a big needle wrapped around with Teflon tape to close that small hole). No one tells you this!  
After I got beyond 50 bar limit, leaking stopped. Now, I have regulated AT44. It got dark while I did this and shot chrony, so I will have to check grouping and accuracy tomorrow.
These are shot strings with JSB 13,43 grain exact jumbo RS pellets.

Before regulator, from 195 bar to somewhere bellow 100 bar, 30 shots

966.1
956.3
951.5
946.7
942.8
939.7
935.8
933.4
931.7
914.4
924.9
906
897.3
897
891.1
869.4
878
870.3
864.6
853.5
854.2
840.4
831.6
818.4
812.5
807.2
784.5
777
767.9
759.7

After regulator, from 195 bar to 100 bar (you will notice the spot when pressure went bellow 125 bar) 30 shots

883.5
875.2
880.4
869.4
868.3
880.6
878.9
866.0
863.2
864.5
868.1
870.4
867.9
868.3
863.7
862.5
864.7
867.7
862.3
865.3
858.8
861.9
852.1
842.7
853.6
834.5
828.8
817.9
814.3
797.5

it looks like I have 22 regulated shots  

and there is no need to drill a hole on a cylinder body, and gauge reads true pressure inside cylinder.

[Pipewelder]

Have you done any more testing with your regulator? I am considering ordering one.

Do you know of any other sources for a regulator for this gun?
Thanks

Gerald

[Stefan]

Unfortenatly, I didn't do more testing (got to work on my disco a bit), but I will in next 15 days. I'll post the results then.

[xschug3]

Stefan, have you had any issues with pumping your Pneuma up? I'm not even sure if you use a pump but I thought I'd ask because I can't seem to put anymore air in my Pneuma passed 100bar.
Just like you described above, the air seems to leak out the fill port once it hits 100bar and it won't allow anymore air to go in the cylinder.

I've had this issue for quite some time now and can't seem to figure it out. Any advice would be appreciated.

[Stefan]

From what you are saying, it seems to me that you have a problem with "non-return" valve on upper part of the air cylinder. I had that problem once, but it was under warranty then, so I got it replaced. Contact Umarex in USA for help, that can be fixed, but I wouldn't do it by my self.

[darryl]

Great results, Stephan! That looks like a pretty flat string to me.

I was about to go into plugging holes, had degassed the tube, then put on a mighty hunt for my 13mm wrench. Can't find it anywhere! All my toher metric wrenches are right where I keep them: in my tool box. Darned thing must have sprouted legs and walked off. Just goes to show; it's always something!