Weird issue with huma reg

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Skydivingmiami

Skydivingmiami

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Mar 18, 2020
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Miami FL
Hey guys! So I'm having a strange issue with one of my regulated airguns. 177 taipan standard. New huma set at 90bar - shooting jsb 10g at 800+...

installed thw new huma and have about 300 pellets through the huma/gun to break in the reg, so today im running a shot string to tune the gun for my jsb 10g at 800fps and I keep having my fps rise slowly every shot, some shots are within 5fps, but its just climbing from 803 to 815 to 818 to 823... and so on. . Any one have any ideas what could be causing this??
 
elh0102 said:
It really doesn't matter. Just bump the Taipan reg up until your maximum HST velocity is 5-10% above your target velocity. Back the hammer down to your goal, and you're done.
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The problem with the Taipan reg is that it requires disassembling the gun to remove it and adjust it. The HUMA reg only requires removal of the end cap/gauge and only takes about 3-5 minutes to adjust.
 
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Sorry it took so long to run a shot string. Here it is. Starting point was 150bar down to under the 90 bar set point on the reg. I'm not touching the hs at all. Just shooting the 10g crossmans. Didn't want to waste my good jsb.

But you can see the speed is slowly climbing chains my poi almost ever shot. I'm not sure what to do. Any suggestions?

Screenshot_20221113-170146_FX Radar.jpg


Screenshot_20221113-170149_FX Radar.jpg
 
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That's a tough one. The wild swings at the beginning of the string when the reservoir pressure is highest...that points to insufficient hammer strike, however there isn't a characteristic bump in velocity toward the end of the string.

What was your tempo when shooting this long string? Particularly with respect to the first 13 shots. Were those taken more slowly and deliberately?
 
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nervoustrig said:
That's a tough one. The wild swings at the beginning of the string when the reservoir pressure is highest...that points to insufficient hammer strike, however there isn't a characteristic bump in velocity toward the end of the string.

What was your tempo when shooting this long string? Particularly with respect to the first 13 shots. Were those taken more slowly and deliberately?
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Didnt know that about the hammer strike. Really cool info.


Tempo was about the same all throughout. 1 shot ever 20 secs.

My reg is set at 90.

I can shoot another string this week starting at 200 bar to see if I can a change. Was thinking of bumping up the reg to 110 or so. See if I get more consistency.
 
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While my comments aren't Huma reg specific, they may be helpful regarding your .177 Veteran issues.

For context, mine was a .22 converted to .177, but comments from other .177 Vet owners make me believe the same problem exits with .177 Vets that started as .177 Vets.

The OEM dual transfer ports is too big for .177, at least with sub 20fpe intentions. Simple as that. I tried all kinds of combinations of reg and hammer tension settings, chasing consistent fps. I could not get there until a friend machined me a smaller transfer port.

This is an example of one size does not fit all. As much as I love Taipan Veterans, and will vehemently argue that theyre about the best overall combination of attributes that exist in a PCP, one of my few gripes is that their OEM transfer port is too big for .177.


I'm sure some will come along and say their .177 Veteran is just fine with OEM transfer port, and they'll probably be telling the truth. I've got three Vets, and each one is slightly different in how it behaves, so there's evidently slight variations from gun to gun, and that can be said for any manufacturer.

Anyway, my inconsistent shot sting issues in a .177 Veteran were resolved by an appropriately sized transfer port.
 
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elh0102 said:
It really doesn't matter. Just bump the Taipan reg up until your maximum HST velocity is 5-10% above your target velocity. Back the hammer down to your goal, and you're done.
Click to expand...
In my experience a 2-3% tune below max hst velocity at a given reg pressure ( plateau) is giving a better ES and overall experience. With “tuning on the slope” as you suggest the ES might be big and the first shot after letting the gun rest for 24 hours or so might be low…( mimicing regulator leaking/creep effect )

also be aware that HUMA has 2 different ranges of regulators

  • Low pressure range: 60-110 bar for 16 Joule / 12 ft/lbs models.
  • High pressure range: 100-170 bar for all FAC rifles from .177, .22 and .25.
And remember that with shorter barrels you might want to use higher reg pressures in order to get shortest possible birst of air behind projectile. ( no air release after projectile left the barrel that will avoid turbulence hence inaccuracy)
 
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Skydivingmiami said:
What do you guys recommend I set my huma at?
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Just depends on what weight ammunition at what speed you want to shoot .
i would start with a jsb pellet in your case ( the most common one in your caliber) then start at something like a 120 bar . The turn the hammerspring up till the speed does not go up more . Then from the point where the hammerspring gives you maximum speed go down 3% in speed. At this setting your rifle is close to optimum tune. If that speed is too high for your liking you repeat the procedure with lower reg setting. If you like the speed higher than up the reg setting and repeat procedure. All this means that for every weigth of ammunition there is a different tune. So choose your ammunition and desired speed and for this combo you create the optimum tune . ( any orher combo requires a different tune . And a tune is a combi of reg setting and hammerspring tension . NOT only the change of one of them ( ideally)
 
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