Kral fill pressure question



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Offline mcoulter

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Kral fill pressure question
« on: December 21, 2018, 02:25:31 PM »
Howdy,

I watched your recent Kral Jumbo video and notice that you're filling to 3300 psi (227) bar and not the advertised 2900 psi (200 bar).    I'm currently experimenting with a .22 Kral Bigmax to see how it performs with minor mods that a caveman like me can easily do to the gun. 

My main interest now is increasing efficiency.  I snipped 3mm from the stock hammer spring and that helped a little but I still essentially have a steady and then falling shot curve.  I expect that the extra air pressure of a 227 bar fill over a 200 bar fill would introduce a lower initial velocity and introduce some curve in the beginning of a longer shot string. 

So I'm wondering your thoughts on using a similar 3300 psi fill on the Bigmax and what suggestions you may have for someone who is interested in making small changes for efficiency vs. large changes for increased power.  I'm happy with it shooting 30-ish fpe with JSB 18s.



A small note regarding the pressures I entered in the strings.  I listed the "as delivered" string as being from 2900 psi (200 bar) but I do believe my gauge is off and reads high.  I adjusted for this in the later "snipped spring" string listing the starting pressure as what I think it really is 2755 (190 bar). 

84 shot string as delivered



90 shot string with 3mm snipped off the hammer spring


Any suggestions for this caveman would be most appreciated  :-)

Oh, the gauge I'm using for my initial fill is from my Joe B. tank and I'm guestimating the ending pressure from my Kral's gauge:




« Last Edit: December 21, 2018, 02:47:35 PM by mcoulter »
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Online oldpro

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Re: Kral fill pressure question
« Reply #1 on: December 21, 2018, 03:49:24 PM »
 link to video your referring to? 
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Offline mcoulter

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Re: Kral fill pressure question
« Reply #2 on: December 21, 2018, 03:56:48 PM »
Sorry, I'm a dummy and mixed up you (Travis) and Troy Hammer.    This is the video I was referring to...

  • Central New York
RWS 34 .177
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Kral BigMax .22
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Re: Kral fill pressure question
« Reply #3 on: December 21, 2018, 05:13:28 PM »
 Other than regulating it two things I would try . Use a twin spring set up/ build a cobra style valve insert.
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