Huma flow restrictor

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SteveKralsAround

SteveKralsAround

Member
Jan 27, 2020
273
61
Gettysburg ,PA, United States
I've been gathering alot of chrony data tuning an airgun and I wanted to reduce the wait time between shots letting the regulator equalize . 

I've removed the flow restrictor screw . Tomorrow I'll find out the results . The tank is already reassembled and aired up to 200 bar . The regulator is set at 125 bar .

So it's too late if I've committed a no , no .....



I was wondering if anyone has tried this before ?
 
A screw be it the grub or one with a head and pull wire ... acts as a flow damper preventing reg from filling too fast having the air flowing around the threads and the seat getting beat up from a rapid fill & closing cycle. many have good luck w/o the screw in place, others not so much.



Just the reason it is there ... nuttin more.



Scott S


 
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Made a nice improvement . Prior to removal it was around 3 minutes . Today I gave it about 10 -15 seconds between shots . I'll leave the restrictor out . The effect I saw (if the gauge is accurate) is after the first shot the gauge was reading 5 bars higher than the regulator was set at . The reg was set to 125 bar , gauge reading at 130 , Deviation was 7 fps . I'm ok with that ....
 
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In continuing with the tuning of my .177 NP-03 project . I now have the regulator set to 90 bar , tank is filled to 200 bar . The gauge reads around 92 bar after the first shot and reaches 90 bar by the fourth shot . It drops below the 90 bar mark at shot 25 . 28 shots is two magazines . The wait time is around 40 seconds .

Now I'm thinking of a middle of the road between using the restrictor srew and not . I am going to fabricate a 3mm screw with a 1 mm through-put hole . I'll start with a 3mm brass tube threaded at a 0.5mm thread rate . then expand the end of the tube to form a head .

I'm going to machine a jig for forming the head while protecting the threaded body .
 
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What would be great is if Huma came up with a form of hole or eyelet, built into the top or side of the BAR adjustment tower of the regulator on the pre reg side of the gun, that makes attachment of a pull wire or fishing line easy. Taking a gun apart to access a reg for fine tuning can be made easier if the reg can just be pulled out and no gun disassembly is needed. 
 
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Update : In my progression of tuning one of the NP-03s . I've been operating at 90 bar , since installing the new design restrictor screw the regulator does not climb over the set point and it has gained another magazine before falling off the reg set point . That's an increase of 18 more shots from a 180cc tank ! Deviation is 7 fps .
 
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