Huma regulator question. Is this right?

[MOhunter]

Hey everyone, needing some opinions on this. Installed a Huma regulator in my Hatsan Vectis .25. I'm pretty sure it's installed correctly-see pics. I installed it so the vent hole will be facing up when inserted back into the air tue. I've pulled it in/out seveal times playing with the pressure and wondering if it's actually venting. It's currently set at 145bar. I think so, but don't hear or feel anything coming out like I do my Huben. So do regulators take a while to vent through all those threads in a pressure tube? If so, maybe I'm okay. Prior to this I was getting a string that made me think it was never consistent, so I took another look at the groove in my threaded receiver (?) and left one turn out when tightening it up. This is my current shot string of 30 shots. I don't know if this is really good or not when looking at the shot string. Please look at these and provide your inputs. Thanks

Shot count: 30
Low: 652
Hi: 707
Avg: 684
STD Dev: 14
Spread: 55 687, 698, 698, 694, 696, 701, 701, 696, 696, 696--707, 677, 677, 680, 682, 689, 701, 675, 677, 682--691, 687, 682, 673, 677, 673, 668, 661, 659, 652

 

[nervoustrig]

The notch you’ve made in the threads looks to be more than adequate, seeing as how it goes below the root of the threads.

Don’t worry about the absence of air exiting the vent hole. There should be no perceptible amount coming from it. The vent is there to allow the escape of an infinitesimal amount that diffuses through the O-rings.

 

[MOhunter]

The notch you’ve made in the threads looks to be more than adequate, seeing as how it goes below the root of the threads.

Don’t worry about the absence of air exiting the vent hole. There should be no perceptible amount coming from it. The vent is there to allow the escape of an infinitesimal amount that diffuses through the O-rings.

Well that's what I thought. So I'm thinking my shot string is pretty much okay then.

 

[Bigragu]

If you’re wondering if you have it in correctly, always point the adjustment end of the regulator towards the fill port of the gun. The high pressure unregulated air is always going to be uphill of that Huma adjustment screw

 

[MOhunter]

If you’re wondering if you have it in correctly, always point the adjustment end of the regulator towards the fill port of the gun. The high pressure unregulated air is always going to be uphill of that Huma adjustment screw

Got it, thanks. Was playing around with it yesterday. How does a person know where to start on balancing the regulator with the hammer spring? Set Reg to a certain pressure and then adjust hammer spring only thru trial and error? And if nothing works, back out hammer spring tension, adjust regulator and start again? Any idea?

 

[nervoustrig]

How does a person know where to start on balancing the regulator with the hammer spring?

Start by finding the velocity plateau...the maximum achievable velocity. Gradually increase the hammer spring tension until the velocity no longer increases.

And then once you’ve found the velocity plateau, dial it back to the velocity knee which is about 97% of the maximum. So let’s say it tops out at 920fps, dial it back to about 920*0.97 = 890fps.

When adjusted in this manner, the extreme spread will be optimized, in the sense that the gun is operating at a state of tune which is relatively insensitive to little variations in hammer strike and/or regulator pressure. This state also makes reasonably efficient use of air.

 

[MOhunter]

Start by finding the velocity plateau...the maximum achievable velocity. Gradually increase the hammer spring tension until the velocity no longer increases.

And then once you’ve found the velocity plateau, dial it back to the velocity knee which is about 97% of the maximum. So let’s say it tops out at 920fps, dial it back to about 920*0.97 = 890fps.

When adjusted in this manner, the extreme spread will be optimized, in the sense that the gun is operating at a state of tune which is relatively insensitive to little variations in hammer strike and/or regulator pressure. This state also makes reasonably efficient use of air.

Ahhh, I see. So don't mess with the regulator at all. Huma rec'd 145bar and since I'm doing hunting, I set it at 150bar. Okay, got it. Increase hammer spring until no more velocity and back off a bit. What if you can't get a decent shot grouping out of it? Reset reg and try again? The reason I'm asking is I was wondering about my groups a little bit yesterday.

 

[Bigragu]

That Hatsan Vectis has a short HPA air tube, and with a reg now installed, you just lost air space uphill from the reg. As you can see from the shot string you posted, after shot 20 it’s starting to head down in velocity, meaning you’re off reg.

I’ve installed a Huma reg in a Vectis once, and at best I got it in the 795-810 fps in 25 cal, with a shot count of barely 20.

Some guns, like the marauder pistol as an example, are just best to be left alone without a reg. Unfortunately, the Vectis falls into this group. There’s not enough air space upstream to give you a decent shot count to begin with, and the installation of the reg just took away some of that volume.
Plus, the Vectis, just like the PRod, doesn’t have much in the way of plenum space, which is regulated air space downhill from the reg.

So, with all that said, let’s look at the glass half full- if you’re hunting decent sized small game ad want good hunting power tune it for no higher than 145 bar, follow nervous triggers instruction to get the best speeds for that reg setting and see how accurate it is at that speed. Lastly, be content with no more than 15 to 20 shots on regulated air.

If it’s higher power, a better shot count, and/or both you seek in one gun, you’ll have to pick up another platform

 

[MOhunter]

Understood. when I was talking shot groups, I was talking consistency, not how much I was gonna get out of it. I know all well I was gonna lose shot count overall, but my wanting to do this was to make everything more even across the board. I'm still getting 20 shots so that's two good magazines. Only after coyotes which probably isn't gonna give me enough chances for that anyway. Yes, he's got good advice, thanks.