Huben Hammerless K1

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Tony, thank you for the tip, right now I have one more form LW to test after that I will definitely take a look at SILCO...

Peole, OK, 300 is really expensive... I am trying to get through with a slightly lower expenses....
I intend to make bigger holes in the barrel clamps to be able to fit the 17,2 mm barrel in. and I will let you know the results I get...
I was persistent enough when contacting huben that they have told me that I can get those spare parts. They told me that I can order them from them directly of from my distributor. I have contacted my distributor several time about this and I did not get any response. That was add since he always respond in the past...
But there is another problem that we both have: we both have version of huben with split shroud and the version they are manufacturing now has a single piece shroud. This means that the hole in the front of the barrel clamp is 25mm to fit in the shroud and only the rear clamp has 12.2mm hole... So you will not be able to get the replacement you need for the front clamp from Huben anymore....
Anyway, I look forward to hearing form you what kind of result you get...

 
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LW offer 3 barrel options with different wall thickness for air rifles. Do you know which one you have?

I could see it being part of the discussion when a new air gun is being spec'd. I.e. Choosing between a stiffer barrel or a lighter gun overall, as the barrel is one of the heaviest components. 

The LW 22 rimfire barrels have a 1:16 twist rate but their bore diameter looks to be identical to their air rifle blanks. The outside diameter is twice as thick as their thickest air rifle blank. I don't know if that small difference in twist rate makes a difference but my guess would be that their rimfire blanks are useable if you want a stiffer barrel and don't care about the weight.

I guess the other alternative is to wrap the barrel in carbon fiber. It isn't difficult. I would suggest doing it properly so the cf is touching the metal vs gluing a ready finished tube over the top. Using a a tube as a sleeve would require a layer of epoxy between the barrel and tube which would reduce the stiffness. 

Perhaps the more obvious point is that LW barrels are accurate on a broad range of air rifles from the no frills budget guns up to premium priced target guns. if accuracy is poor in a gun with a LW barrel, my first assumption would be that the barrel brand is not the issue. 

There are a number of ways to make a gun inaccurate even if it started with a good blank. Poor machining would be up there. Poor prep and dirt would be another. The nature of the air source / power plant and it's efficiecy / consistency. Too much pressure caused by a poor stock fit or screws too tight. The pellet choice etc etc.

If you don't know for sure what the issue is, there is a good chance it will still be there once the barrel is replaced. 
 
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You have to go to the DE LW sight. The one that fits Huben is listed under 12mm (in reality it is lightly more, about 12,2mm)
http://www.lothar-walther.de/163.php

Weight to barrel thickness is always a compromise.

DE LW sight offers .22 LR barrels forom 10 mm on...:
http://www.lothar-walther.de/160.php

Damping the harmonics with rubber or any other light materials can be effective but it take some experimenting... It can also make it worse. Carbon fiber is very strong but is is flexible so it will not make the barrel more rigid but it might dampen the vibration by absorbing it because it is flexible. That is why I intend to try and get rig of harmonics by making a heavy ring that can be tighten on any part of the barrel, so I will be able to move it and test for accuracy.

Yes, I agree with you but my test showed different results... First of all, there is no barrel in the world that would shoot well form 8 joules to 100 joules form extremely light pellets to slugs. For some reason (I assume it is the vibrations) stock barrel does not shoot well with standard light pellets at low velocities... But when you open the power up, the gun starts to preform very well. So you can shoot light pellets at extremely high velocities but only at close ranges of course, at longer ranges they are unstable (they are not built for those velocities). But when you put in a heavy pellet (like JSB beast) or bullet, they are not accurate again (I assume it is the vibrations again)... My barrel is 17 mm thick and has a twist of 16.3. With this barrel I can shoot light pellets at low velocities with reasonable accuracy and extreme accuracy with JSB beast at high velocities but only up to 50 meters... If I shoot beasts with velocities under 1000 FPS, the pellet curves at a certain distance (under stabilized) , but if I shoot them with velocities over 1000 FPS, they they are stable up to 50 meters and then they start to spiral because a pellet is not made for those velocities. The first thin of Beast were stable over 70 meters, but the ones I get from JSB now are unfortunately not anymore...I think that I will solve the problem with Beast with a barrel with faster twist (14.4). That way they will be stable under 1000 FPS... No slug has preformed well so far, but they do have a stable flight (no spiraling). I assume that there is still some vibration left at higher pressures (slugs produce much higher pressures) because the back side of my barrel is still only 12 mm thick. That is why I intend to have the whole 14.4 twist barrel 17 mm thick and hopefully it will shoot well with beasts and slugs. It will probably not shoot well with light pellets but I can live with that. This is the whole story of my experiments so far....
That is also why I know the gun is not the problem.
 
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"Gregor"You have to go to the DE LW sight. The one that fits Huben is listed under 12mm (in reality it is lightly more, about 12,2mm)
http://www.lothar-walther.de/163.php

Weight to barrel thickness is always a compromise.

DE LW sight offers .22 LR barrels forom 10 mm on...:
http://www.lothar-walther.de/160.php

Damping the harmonics with rubber or any other light materials can be effective but it take some experimenting... It can also make it worse. Carbon fiber is very strong but is is flexible so it will not make the barrel more rigid but it might dampen the vibration by absorbing it because it is flexible. That is why I intend to try and get rig of harmonics by making a heavy ring that can be tighten on any part of the barrel, so I will be able to move it and test for accuracy.

Yes, I agree with you but my test showed different results... First of all, there is no barrel in the world that would shoot well form 8 joules to 100 joules form extremely light pellets to slugs. For some reason (I assume it is the vibrations) stock barrel does not shoot well with standard light pellets at low velocities... But when you open the power up, the gun starts to preform very well. So you can shoot light pellets at extremely high velocities but only at close ranges of course, at longer ranges they are unstable (they are not built for those velocities). But when you put in a heavy pellet (like JSB beast) or bullet, they are not accurate again (I assume it is the vibrations again)... My barrel is 17 mm thick and has a twist of 16.3. With this barrel I can shoot light pellets at low velocities with reasonable accuracy and extreme accuracy with JSB beast at high velocities but only up to 50 meters... If I shoot beasts with velocities under 1000 FPS, the pellet curves at a certain distance (under stabilized) , but if I shoot them with velocities over 1000 FPS, they they are stable up to 50 meters and then they start to spiral because a pellet is not made for those velocities. The first thin of Beast were stable over 70 meters, but the ones I get from JSB now are unfortunately not anymore...I think that I will solve the problem with Beast with a barrel with faster twist (14.4). That way they will be stable under 1000 FPS... No slug has preformed well so far, but they do have a stable flight (no spiraling). I assume that there is still some vibration left at higher pressures (slugs produce much higher pressures) because the back side of my barrel is still only 12 mm thick. That is why I intend to have the whole 14.4 twist barrel 17 mm thick and hopefully it will shoot well with beasts and slugs. It will probably not shoot well with light pellets but I can live with that. This is the whole story of my experiments so far....
That is also why I know the gun is not the problem.
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Carbon fiber is stiff - that's one of it's main attributes. Depending on the application, that can be good or bad. On the one hand it is very strong but on the other, it will bend very little before it breaks. For applications where flexibility is a desirable quality, fiberglass would be a better option. For anything that needs too be stiff with the least amount of flex, carbon fiber is perfect. It is far stiffer than steel or aluminum weight for weight .

I use CF to make a variety of stuff including air rifle stocks and if laid correctly, it has zero flex. The key is use enough layers for the desired strength and lay the fabric in the right direction. It is particularly strong in cylinder shapes so it's hard to imagine a more perfect material to add strength to a barrel without making it unreasonably heavy. 

As for matching the twist rate to the pellet speed, I'm not sure that is done with air rifles. As far as I can tell, pretty much all air rifles designed for diabolo pellets use the same or a similar twist rate. LW (America) only seems to offer one twist rate for air rifles for all calibers. It's not like a 600fps 10m gun uses one twist rate and a 950fps hunting rifle uses another. 

Firearms have a broader range of twist rates but their ammo is not drag stabilized and there is a broader range of speeds from 600 fps to over 3500fps. 

Tom Gaylord did the only study I am aware of for air gun twist rates. Check it out on the PA blog. From memory, the standard essentially universal air gun twist rate seemed to be the most effective on average. Faster twist rates did ok at close range but not past a certain distance.

It doesn't look like there is anything unusual about the Huben power / pellet speed or ammo selection that would require a different TR to every other accurate 22.
 
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"skorec"Beast ( 240m/s ) and Monsters (270 m/s ) work verry well. Aproximately 2x MOA at 52m.
It is one of my better grouping I have reached from PCP Air Guns.

JSB heavy Ultra Shock and HN Rabbit Magnum power was up to 10x MOA.

Sory I do not know how to add the pictures ( *.JPG ) inside the post.
Click to expand...
2x MOA at 50 yards would be 1.047 inches. So pellet landing within a radius of .524 inches would be iffy for squirrels beyond 25 yards. I really want this gun to be more accurate. Everything else about it is incredible. 
 
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Is it possible? 

 

 

yes. Is it practical? Probably No. Barrel & machining will set you off in way wrong price range.But if someone is in to machining and tinkering it can be fun. Here are important notes about customizing barrel for huben. 

1. Twist, People need to realize that not twist is stabilizing projectile. Rotating speed aka RPM does. RPM is proportional to velocity divided by twist

RPM = V X 720/Twist Rate.

There's plenty of research of subsonic ballistics, but air gun barrel manufacturers still prefer 1:17 which was good for 10 and 25meter target competitions. I started with 1:10 subsonic match .22 barrel.


2. From what I see barrel in Huben must be fixed - no flex or vibration. Fully floated barrel is impossible by design. Original LW barrel fits very lose in barrel brackets - there 0.05mm clearance between barrel and bracket. So when fired barrel harmonics force barrel to hit brackets and bounce back - BAD.

I also hear that Huben changed design of front barrel bracket to hold shroud, not barrel - recipe for even more out of whack accuracy.



Barrel needs to be machined so that clamp screws fix it hard. I machined go/no go gauge:



3. Forcing cone. One of principal mistakes of Huben was to use revolver design where air pushes pellet from revolver cylinder in to barrel. This design has serious safety problems (later on that) plus barrel needs to be perfectly aligned with cylinder and gap should be less than 0.001in (0.0254mm) 

Machining forcing cone:



Covered magazine with DYKEM Blue, 



Adjusting barrel cylinder clearance. Barrel should protrude surface 0.27mm.



0.27mm is pretty small - blade for comparison:



If your gap is bigger you'll get air blow-by in to your neck, fps loss and very loud sound. 
I do not suggest setting gap by eye.



heres good movie about that:



4. Muzzle end machining:





Few random notes.

1. Build quality is good.

2. Air system is very effective. Power - Huben starts where everybody else ends.

3. Product is far from being final, accuracy, safety etc. It's not outdoor/survival gun, if sand can get between magazine and barrel it will make this gun defunct and possible unsafe. Definitely not ready for average air gunner.

4. Blow by revolver design adds more complications than problems that it solves. Spring loaded linear magazine will be probably best.

5. When you buy it - support ends right after money exchange hands. My dealer does not stock Huben anymore and has "problems" receiving my emails after I paid (emails worked just fine before I paid:)

5. Huben factory does reply emails, but that's about where it ends, any attempts to order parts ended up nowhere so far. 


 
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