Canadian Airgun Forum

Safety valve?
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Author:  EdLena [ Sun Sep 11, 2016 6:48 pm ]
Post subject:  Re: Safety valve?

Voltar1 wrote:
Looks good
Tell me more of your setup. Whose reg? What fpe are you atnow?
As to the tube, the Hatsans have the worst tubing I have worked with so far. And they seal at a larger diameter so thinnest wall is where it seals. Compounding that the axial force is higher pushing on the threads.
I do not recall Hatsan or any other pcp with a safety valve.

I've had the BT65 for 2 weeks now and right out of the box the big brute was shooting a 52fpe with .22 21gr at 1040fps!
I say brute because I recently sold my lighter AT44 long in .177 which was a pleasure to handle and I really miss the lever action cocking. Yea in retrospect I should have bought another AT44 in.22 and hogged out the valve seat and ports but I've always been an impulsive buyer.
Anyway I bought an Altaros regulator which they set to 135bar. I wanted to shoot 21gr pellets at 900fps but the 150bar I set the reg to is shooting them at 925fps. I was ok with that but it only shot 18 rounds before dropping velocity below 150bar when being filled to 200bar. Being an OCD nut I couldn't live with that having 2X10 shot magazines. I guess I took the easy way out and just added a little extra air. I now plan (thanks to the forums reaction) to lower the reg a little so I can get my 20 shots near 900fps.
The AT44 also had that tiny hole near the air fill end drilled nearly through. I think it's an inexpensive burst valve setup.

Author:  EdLena [ Sun Sep 11, 2016 7:00 pm ]
Post subject:  Re: Safety valve?

Chevota wrote:
I personally wouldn't worry about that pressure diff, but people rarely consider me a safe type. For example I always filled my Mrod to 3200 vs the 2900 max. I would work on getting the thing dialed in to max efficiency, like a hammer debouncer which gave my Mrod a LOT of extra shots

You were the first to admit overfilling a little and I appreciate it. After catch hell I was feeling like I was the only bad man out there lol.
Fortunately the Hatsan At44 and this monster have a built in hammer debouncer. I'd like to know if there are other efficiencies I can use other that the 5 screw mod though.

Author:  Whitewolf [ Sun Sep 11, 2016 7:51 pm ]
Post subject:  Re: Safety valve?

In my line of work, I work with huge amounts of pressure and volumes of it at a time. Something which needs tobe respected, there is a reason for a max fill of 200bar upon your air rifle. Those who fail to apply this respect have found consequences with their judgement..
..tic toc tic toc

As for your hole in the body tube is due to the fill end block has a smaller diameter oring for sealing. In engineering theroy and calculations the smaller diameter will fatigue out sooner then the thicker one upon the valve. Relief exhaust port is what it is, not a valve. Thats not taking in consideration the amount of times you reuse that same oring threading in and out the valve, which wears the sealing edge of the oring. As Walter also pointed out the Hatsans have a far poorer quality of tubing as per other manufacturers of airgun reseviour tubes. The threads are not pressure relieved upon the Hatsans. Something that is now being finally used in the manufactoring of PCPs nearly 30 years later. But has been an engineering practice for pressure vessels since the early 70's.

Author:  EdLena [ Sun Sep 11, 2016 7:59 pm ]
Post subject:  Re: Safety valve?

I went ahead and lowered the regulator to what Altaros said would be 135bar and filled to 200bar. To my contentment it shoots 21gr at an average of 905fps and 18.? at 955fps all with the least ES I've ever experienced. However the 20th shot was 891fps. Sure enough the meter showed 135 bar. In the future I'll fill to 3000psi. :wink:

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