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Huma Regulated Bsa Ultra

Discussion in 'Technical' started by Wing-span, Jun 8, 2019.

  1. Wing-span

    Wing-span Hello Peter Rabbit. Shhh... go to sleep.

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    XTX Air sent me a Huma regulator and the 4mm internal diameter transfer port for my Ultra. The instructions were clear and the fitting was easy. The reg was factory set at my request to 95bar.

    The rifle went back together and on testing is pushing .177 8.4gn AADF at 11.8ft lbs, but it seems thirsty with the air (10 shots for a 3rd of the 'green' part on the gauge! ). I'm guessing I need to find the sweet spot with a little focused tuning. Does anyone have any relevant experience and can chime in with a few suggestions and pointers? Maybe the cylinder gauge is less relevant now, apart from showing initial pressure after a charge to 232bar?
     
  2. GeeTee

    GeeTee Posting Addict

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    Hi,i too have just fitted a Huma Reg from XTX to my Ultra,what i find now is my rifle is now considerably noisier which i don't see how & i will agree with you about the air consumption,i have a 325mm air cylinder & my shot count has dropped from 110 to 70?

    I will speak to the guys at XTX next week to see what/where is happening
     
  3. Blackmax

    Blackmax Forum Rude Guy

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    My advice is don't touch a Huma! Look at the Robert Lane regs.
     
    sharpsman likes this.
  4. Leon83

    Leon83 Engaging Member

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    Increase the hammer spring tension and shoot through chrono until you reach highest velocity (point where increasing hammer spring tension does not increase velocity). Note that velocity and deduct ~4%. For example if you reach 815fps -4%=782fps. Then loosen hammer spring tension to 782fps. It would be the optimal velocity for set pressure on your reg.
    If your optimal and required velocity is to low, set the reg higher; if to high set the reg lower.
     
    Last edited: Jun 8, 2019
  5. cloverleaf

    cloverleaf Super Moderator Staff Member Mod/Admin

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    There's not a lot wrong with Huma regs.

    How many shots per charge are you getting? I managed to get mine to nearly 55 in its most optimised state (mostly XTX and standard R10 bits, no debounce device etc on the striker). You might find this thread useful ;)

    Interesting method. Not sure I agree with it though as ideal reg pressure falls as striker energy is reduced, so your method will end up with the reg pressure too high (which sometimes isn't a bad thing although can affect consistency and give a potentially illegal spike coming off-reg).

    In addition to this, are you suggesting that this is done before or after fitting the reg? Looking for a velocity curve with the reg fitted isn't got to get you very far! I can kind of see the logic if doing the test pre-reg fitment as the reduced plenum volume with the reg usually means the regged gun likes a slightly higher operating pressure than the velocity peak on the unregged gun would suggest.

    Also your method doesn't make any allowance for variation in velocity at the initial setting - what if it's significantly higher or lower than the target velocity?
     
    Last edited: Jun 9, 2019
    Seamaster likes this.
  6. Leon83

    Leon83 Engaging Member

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    It takes time, but works for me. When I find peak velocity I know that the valve is being open 100%, by reducing hst I know I do not open the valve longer then necessary. I usually get 2-3 usable shots below reg pressure, never with illegal peak if hst is lowered by mentioned ~3-4%.
     
  7. robs5230

    robs5230 Oversprung

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    Interesting this as the last Ultra SE i regged also seemed a little excessive on air use and i also specced a 4mm TP. I didn't spec the reg pressure though, just specified barrel length and calibre.
    The first 3 I regged, I used the lightweight guide but tye standard spring and got around 50 on the money shots from a 220 bar fill.
    The last one was less. I'm wondering whether XTX or Huma have decided that a lower reg pressure is needed ?
    I'm wondering why you specced your reg at that pressure ?
    I'm about to reg another Ultra and may well spec reg pressure higher than 95 though I don't know what Darrin would normally set at for .177.
    I also had issues with hammer springs and had to source a non standard length one for my last Ultra. Can I ask what length spring you have in it ?
    Cheers Rob
     
  8. Blackmax

    Blackmax Forum Rude Guy

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    The trouble with that is you won't have the regulator set at its optimum efficiency setting.

    As for the Huma, the issue is the sealing disc, cheaper to manufacture but not as good as a sealing face contained within a metal stem.
     
    sharpsman likes this.
  9. JLB

    JLB Busy Member

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    I fitted a HUMA reg from XTX Air to my .177 Hornet a few months ago, came pre-set at 85bar. I haven't had any issue's with it. Not done a number of shots test with it yet though.

    John :)
     
  10. Blackmax

    Blackmax Forum Rude Guy

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    I'm not sure emptying the prechamber is that important, whilst I do except that inefficient hammer tension needs to be eliminated. I experimented with a larger plenum in sub 12 guns but found bigger wasn't better.

    As Mike pointed out my concern would be any off reg spike.

    I look for the most efficient regulator pressure to give best consistency noting any off regulator spikes. I set the regulator pressure roughly based on calibre and barrel length, I then adjust based on shot spread and any off reg spike. I've found the point where I get a slight spike to give the best shot to shot consistency.
     
  11. robs5230

    robs5230 Oversprung

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    Hi Mike
    Your link to your thread isn't working. Could you sort that link as I'd like to read that again. Thanks
    Very interested in how you set yours up as I'm just about to do another
     
    cloverleaf likes this.
  12. Leon83

    Leon83 Engaging Member

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    I think this the set point I was writing about.
    Regs are built to work between specified pressures, I think the closer to the middle of this pressure range the better. I would rather look for good hammer spring working well with return valve spring. Both should work in their middle ranges to achieve shot to shot consistency.
     
  13. cloverleaf

    cloverleaf Super Moderator Staff Member Mod/Admin

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    Fair enough.. again not sure I agree with that but if it's working for you..!

    Ta for letting me know - sorted now ;)
     
  14. TrickyDicky

    TrickyDicky Life in the slow lane

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    That's an interesting point about the plenum size... as apparently when tuning an R10 JB makes a spacer to reduce the plenum volume, i did this myself when trying to get my Huma reg to work properly....but to no avail now back with the std reg but still have the spacer fitted.
     
    Blackmax likes this.
  15. Leon83

    Leon83 Engaging Member

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  16. robs5230

    robs5230 Oversprung

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    Fantastic read Mike, apart from the end where you lost faith in BSA :D

    For the money, i don't there's a better rifle on the market. My preference is the single shot with beech stock.
    The SS negates any mag feeding issues and the raked comb seems to offer any head position needed.

    I'm leaning towards the XTX stainless striker and may try and keep the standard hammer spring, though I have a bagful here of varying sizes including a 1.3 spring. I'll also consider removing that buffer. ANother thing i did on my last one which I will repeat is the addition of a thin PTFE / delrin spacer between the hammer spring and the adjuster.

    Reg pressure - I'll get Darrin to set me one at 100 as a starter I think.

    Pellet wise I too will be aiming to set for 7.87 whilst remaining safe with 10.34. The 7.87's continue to have the devasting killing effect I've come to love in the field. I may well even set power mid 10's as I do with my .177 springers. It seems to be the magic numbers 7.87 and 787fps (therabouts) that are ideal.

    Barrels - If i do end up with a duffer (I haven't as yet and my 2 other ss se's are still bang on) i actually think the Ultra is worth rebarrelling. As a hunting rifle, I've not found anything better despite the huge sums of money I've thrown around in the last couple of years.

    Cheers Rob
     
    Tim_B and cloverleaf like this.
  17. Blackmax

    Blackmax Forum Rude Guy

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    I'd be interested to hear what shot velocity spread you're getting John.
     
  18. Wing-span

    Wing-span Hello Peter Rabbit. Shhh... go to sleep.

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    Right! Raining heavily this evening so I went to the garage to do some indoor tweaking of the Huma Reg and hammerspring settings. Was I successful?... so far yes. I dialed back the hammerspring by 1.5 full turns (anti clockwise). In doing this in half turn increments I noted that the Fps reduced and the usage of air was more efficient by observing the gauge on the rifle. I left the regulator at 95 Bar. In the end I settled with the same .177 8.4gn AADF now leaving the barrel at 773 Fps (11.1 ftlbs).

    I think I can get up to 65 usable shots from a full charge. (BSA Ultra XL .177)

    My shot string test results (Apart from the 1st and 10th, I only fired a pellet every 5 shots);
    Shot 01, 232bar, 767fps
    Shot 10, 210bar, 769fps
    Shot 15, * , 772fps
    Shot 20, 190bar, 774fps
    Shot 25, * , 772fps
    Shot 30, 170bar, 770fps
    Shot 35, * , 767fps
    Shot 40, 150bar, 775 fps
    Shot 45, * , 772fps
    Shot 50, 130bar, 775fps
    Shot 55, * , 775fps
    Shot 60, * , 771fps
    Shot 65, * , 768fps
    Shot 70, 095bar, 755fps
    Shot 75, 080bar, 738fps
    Shot 80, 070bar, 706fps
    Shot 85, 055bar, 664fps
     
    Last edited: Jun 11, 2019
    Tim_B likes this.
  19. robs5230

    robs5230 Oversprung

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    BSA Ultra XL ?? or SE ??

    Thats a hell of a shot count if its an SE. And 8fps variation in 65 shots looks consistent enough.

    What fill pressure did you start at and what pressure did you shoot down to ? Worth rechecking the first and last 10 shots (shot 55-65) just to see if they are consistent.

    You mentioned the reg and 4mm TP. Did you also get a plastic spring guide and new hammer spring or are you running the original hammer spring and metal guide ?
     
  20. Wing-span

    Wing-span Hello Peter Rabbit. Shhh... go to sleep.

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    The rifle I have fitted the Huma in is the BSA Ultra XL.

    The only new parts are the reg and the 4mm transfer port. All other parts are original. I started at 232bar and in the test I took it down to 55bar.
     

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