Daystate Huntsman Huma Tuning

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EPG

EPG

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Dec 12, 2020
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I installed a Huma regulator into my Huntsman Regal - one of my objectives was to extend usable shots for target shooting.

My Regal is one of the last ones produced, so it has the 250 bar max fill pressure.

After installing the reg with the reg pressure set at 165 bar, I got 27 shots on the reg shooting 15.89g at 885fps.

I lowered power using a 3mm long allen to adjust length of hammer throw - down to 858 fps.

I now have a nice shot string of 32 shots at 855-863fps with the 15.89g. Accuracy is very good with this velocity.

It fell of the reg rather quickly: 858-835-812 for shots 32-33-34.

Is 32 shots on the reg in the 860fps range with 15.89 about all I can expect, or should I be able to tune (adjust reg pressure, etc) to get 40-45 shots at this power level?

My understanding is that factory Huma regulated Huntsmans get about 42 shots on the reg.

I’d appreciate input from those that have actually tuned a Huntsman with Huma. I have lots of experience tuning other rifles - so I’m looking for input specific to Huma regulated Huntsmans.

Thanks,
-Ed
 
My .20 cal Regal with factory installed reg is set at 150 bar according to the Huma gauge!
I get about 4 mags on a 250 bar fill with 15.89 heavies shooting at 890fps. I did bump up the hammer spring a bit from factory settings to get that speed.
I'm thinking you could get away with a bit lower reg pressure than that in .22. maybe 140 bar or so and tune with the hammer spring from there! Not having the second gauge is gonna make it kind of trial and error and testing though.
 
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Mine is a 177 and the reg is untouched from the factory. I did touch the HS a bit to get the MRD speed up. The reg appears to be around 125
I ran a string today.

Revere-MRD.jpg
 
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I find that the onboard regulator gauges to be useful as a reference, and to show when the gun falls of the reg,
Beyond that they are not necessarily precise.
(All make, not just Daystate)
I use a Huma Regulator Tester
They are not very expensive, but shipping bites it.
They come occasionally in the classifieds

Once you have set the reg you can mark the screw position on the body as well as compare it to the reading on the gun's gauge

Hope this helps
Edward

huma-air.com

Huma-Air Regulator Tester

Huma regulator tester for testing and adjusting your Huma regulator
huma-air.com huma-air.com

 
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Update - seeking input:

My original post had my Huma regulated Regal getting 30 shots from 880-885fps before falling off reg.

Then I reduced velocity via the hammer throw adjustment to 856-863fps - this got me to 35 shots before falling off the reg.

Today I pulled the Huma reg and dialed it down about 15 bar per the scale on the reg. On the gun gauge, the previous setting showed 175 bar and after my 15bar reduction (per Huma scale) the rifle gauge now shows 168 bar. I was aiming for 160 - so not sure why gauge didn’t track with Huma scale.

Leaving the hammer throw alone, the rifle now shot the shot string below.

During the shot string I was target shooting. The rifle shot very accurately at this reduced velocity. It seems I got 65+ shots before velocity dropped below 740fps. The gun gauge shows 165bar after the 69 shot string - so it looks like I hit the reg set point.

Questions:

Why would the rifle shoot fast for a few initial shots after the fill - and then for one shot (#27 in red) after a few minute delay between cards?

Why would there be a gradual decrease in velocity throughout the shot string if regulated?

There is a little grub screw in the top of the Huma reg (in screwdriver slot) - what is its purpose? I didn’t tighten it down as it seemed it would go far down into the reg.

I’d love to stay at this velocity (about 20 ft/lbs) for the shot count as the rifle was very accurate - even in the wind gusting to 25mph (shot a 192 30 yard Challenge card and then a 190 30-Masters card during the string). But I’d like to smooth out the “spikes” upward after the fill and then between delays - suggestions?

Thanks,

-Ed

Regal with Huma at 168 bar per Regal gauge.jpeg


IMG_4866.jpeg
 
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Florida_Man said:
There are much smarter people with more knowledge base, to me it's like the regulator is not working. But if that is the case, I wouldn't expect a string like that. Very odd. Sorry, I am no help.
Click to expand...

Thanks Florida_Man.

Its appears the regulator just needed to settle in after adjusting.

I refilled the rifle to 250bar and my next shot string was 745-754fps across 58 shots. Accuracy was very good.

So I’m going to leave it at this approximate 20ft/lb level for a bit - I’m liking 58-62 regulated shots for target shooting.

-Ed
 
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EPG said:
Thanks Florida_Man.

Its appears the regulator just needed to settle in after adjusting.

I refilled the rifle to 250bar and my next shot string was 745-754fps across 58 shots. Accuracy was very good.

So I’m going to leave it at this approximate 20ft/lb level for a bit - I’m liking 58-62 regulated shots for target shooting.

-Ed
Click to expand...
Makes sense. When I put a new Huma reg in my Concept (same reg as the huntsman) it dropped a little. I think once it settled in it was like 10 fps lower, but I didn’t get the constant drop like yours did.
 
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Ed,

When I got my Caiman it gave me a declining shot string because the Huma regulator was not venting to atmospheric pressure between shots. It could fall as much as 42 fps over 10 shots. But sometimes it did a little better and only fell 37 fps over 33 shots. But it always would fall until it sat overnight and finished venting. I do not know what the vent path is for your regulated Huntsman but I would check that. It would be interesting to know what happens if you let the gun sit an hour. Does the velocity come back up? My Caiman did not, it took a lot longer. But your velocity doesn't seem to be falling as fast. I fixed my Caiman by giving it a path to vent the washer stack.

My Caiman has a small hole in the side of the air tube for the regulator to vent. Since your huntsman did not come regulated I wonder if it has a hole like that. The vent has to come out of the area of the regulator where the spring washers are because it is that washer area that has to get to atmospheric pressure. When it doesn't the regulator setting is effectively different because there is additional pressure on the regulator seal to the bulk air. I don't know that a hole in the airtube is necessary but somehow the washer stack has to vent.

When my first shot velocity is off it normally means the gun thinks I messed with the hammer spring too much. Typically it is a low velocity from turning the hammer spring too far down from the peak velocity for the regulator setting. My guess is having too much hammer spring for the regulator setting could also affect first shot velocity.

Jim
 
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JimD said:
Ed,

When I got my Caiman it gave me a declining shot string because the Huma regulator was not venting to atmospheric pressure between shots. It could fall as much as 42 fps over 10 shots. But sometimes it did a little better and only fell 37 fps over 33 shots. But it always would fall until it sat overnight and finished venting. I do not know what the vent path is for your regulated Huntsman but I would check that. It would be interesting to know what happens if you let the gun sit an hour. Does the velocity come back up? My Caiman did not, it took a lot longer. But your velocity doesn't seem to be falling as fast. I fixed my Caiman by giving it a path to vent the washer stack.

My Caiman has a small hole in the side of the air tube for the regulator to vent. Since your huntsman did not come regulated I wonder if it has a hole like that. The vent has to come out of the area of the regulator where the spring washers are because it is that washer area that has to get to atmospheric pressure. When it doesn't the regulator setting is effectively different because there is additional pressure on the regulator seal to the bulk air. I don't know that a hole in the airtube is necessary but somehow the washer stack has to vent.

When my first shot velocity is off it normally means the gun thinks I messed with the hammer spring too much. Typically it is a low velocity from turning the hammer spring too far down from the peak velocity for the regulator setting. My guess is having too much hammer spring for the regulator setting could also affect first shot velocity.

Jim
Click to expand...
I installed a Huma reg in a Kral Puncher Mega ( a non regulated gun ). The instructions said to remove the o-ring at the receiver end of the pressure cylinder. That allows the reg a path to atmosphere through the threads. That worked. If that doesn't work then the gun will need modification, like cutting a slot in the threads for the air cylinder in the reciever (perpendicular to the threads) or a hole in the cylinder. No experience with that, and I don't recommend it without getting more details, maybe Huma can help?
 
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Hi John and Jim,

Thanks, regulator settled in and is working fine now 9fps spread across 60 shots.

My Regal was one of the last ones made - so it even had the reg vent slot pre-cut across the threads (probably Daystate makes this cut for all - and later can make all rifles regged or unregged without any additional machining). I did remove the 2 sealing o-rings on the cylinder so that the reg could vent.

It’s a super easy install, but nothing is externally adjustable, so you want to have a good idea of where you want to be before installing.

-Ed
 
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Ed,

Glad it settled down and is working so well. My Caiman problems were partially because it was so well machined and partially bad assembly, I think. Somebody used an abundance of silicone grease on the end of the regulator body where it mates to the plenum piece. That is the vent path but it doesn't work if you smear up the metal to metal interface with grease. But once that was fixed it still wouldn't vent properly until I removed a portion of one thread that was covering the vent hole with a diamond burr. If the threads had not been so well machined it would have worked fine, I think. It works fine now but my ES is usually more than 9 (but under 20). It's producing low 30s fpe on a 100 bar reg setting so I think the flow path must be very open. That does not tend to reduce ES or std deviation.

Jim
 
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