Huben Any issues or problems with Huben gk1 please share your experience

[steve-l]

As a follow-up to this, I finally was able to contact the Huben factory yesterday of this issue and I have received an acknowledgement. We will see what, if anything this brings..

I received a reply from the factory> > > see below:
Dear Steve,



Thanks for choosing Huben GK1!



Thank you very much for your feedback! We recheck the Silencer Kits, the adaptor is no problem, but we find a fault on the inner part, the measurement of inner part we used .22 caliber data, so current Silencer is not suitable for .25 GK1.



We have arranged to adjust the Silencers in hand, and will contact all of our dealer to check how to replace the Silencer for previous .25 caliber GK1, pls kindly wait for the contact from our dealer and very sorry for the trouble!

 

[steve-l]

From this Huben reply, it is clear they do not think the problem is the adaptor. Perhaps English is not their first language. The HUSH silencer does not suffer this clipping issue because the HUSH bore will clear a 9mm pellet it is so huge. That is a separate issue and not at all relating to the adaptor cant problem.

 

[steve-l]

What does the adapter you were using look like? Maybe you already posted this… I think there are at least three different adapters out there. i’m unclear on the details

MrP,
I'm using the adaptor supplied by Huben. I bought both my GK1s in Spain. In point of fact cockeyed adaptor mounts is actually quite common and it is usually NOT the moderator that causes this. Take FX rifles as an example. The moderator attaches to an adaptor that screws into the shroud. I have not had an issue with mine, but others have. It is a really good idea to own a test rod that can be inserted through the mounted moderator and slip into the barrel. Very simple. The end of the rod should be a close fit to the land diameter of the barrel at barrel exit for a length of about 2". It should be long enough to extend beyond the end of the moderator. Then when placed through the mod and into the barrel and then viewing the rod exit on the mod, if everything is correct, the rod should be in the center of the mod bore. It is easy to see if it is not. This test rod delivers peace of mind and prevents damage.

I know they are not for sale anywhere that I am aware of. I suppose I could make some, if anyone is interested. They would not be expensive to make. The only tricky part would be knowing the exact land diameter of the barrel, so that diameter would have to be supplied to me. Please also note many guns have chokes, so it is important to get that number right. The easiest way is to use pin gauges as go/no go gauges. If you don't have any, go see your local machinist. It only takes a minute to test. It is best to use aluminum as it is softer than the steel of the barrel and will do no damage to either the barrel or the crown.

 

[Nomadic Pirate 66]

No problem here using a no brand .25 LDC with the adaptor supplied by Huben.

 

[scottblair]

MrP,
I'm using the adaptor supplied by Huben. I bought both my GK1s in Spain. In point of fact cockeyed adaptor mounts is actually quite common and it is usually NOT the moderator that causes this. Take FX rifles as an example. The moderator attaches to an adaptor that screws into the shroud. I have not had an issue with mine, but others have. It is a really good idea to own a test rod that can be inserted through the mounted moderator and slip into the barrel. Very simple. The end of the rod should be a close fit to the land diameter of the barrel at barrel exit for a length of about 2". It should be long enough to extend beyond the end of the moderator. Then when placed through the mod and into the barrel and then viewing the rod exit on the mod, if everything is correct, the rod should be in the center of the mod bore. It is easy to see if it is not. This test rod delivers peace of mind and prevents damage.

I know they are not for sale anywhere that I am aware of. I suppose I could make some, if anyone is interested. They would not be expensive to make. The only tricky part would be knowing the exact land diameter of the barrel, so that diameter would have to be supplied to me. Please also note many guns have chokes, so it is important to get that number right. The easiest way is to use pin gauges as go/no go gauges. If you don't have any, go see your local machinist. It only takes a minute to test. It is best to use aluminum as it is softer than the steel of the barrel and will do no damage to either the barrel or the crown.

This point that Steve is making, and made previously on this thread, is the easiest, and can be the most accurate way to test for interference from a moderator.
I've been doing it for decades when I used to install muzzle brakes on rifles, that extended past the barrel's end.
I used to use a wooden dowel, but now use a carbon rod.
NOTE; once I have the rod inserted through the mod and into the barrel (deeper the better), I rotate the rod by quarter turns as I inspect the clearance at the exit hole. The reason for that is to eliminate any era if the rod is not PERFECTLY straight. Even carbon rods can have a slight bend to them, especially long ones used to check rifles.
Don't disregard how important this simple method is to use.
Have fun!

 

[Airgun-hobbyist]

This may be considered an issue or a problem by some of the air flow and power tinkerer's here... It is the .25's bore at the valve, partially obstructed airflow by a decent percentage with these two screw tips. I'm not sure if I am going to mess with porting it or not, as I'm pretty happy with the shot string for two magazines worth of shots. We'll see what happens when I take it apart for cleaning.

 

[wgd]

I have a brand new GX CS2 that fills all my guns except my GKs and my K1. I've tested the pump its fully functional. I can fill my guns with a tank, I just can't fill with a compressor. What am I doing wrong? Thank you in advance!

 

[bernieorosz]

I have a brand new GX CS2 that fills all my guns except my GKs and my K1. I've tested the pump its fully functional. I can fill my guns with a tank, I just can't fill with a compressor. What am I doing wrong? Thank you in advance!

I have a GX E-L2 battery version of the CS2. It fills my GK1 to 300 bar, and other non-Huben guns perfectly fine.

Since the CS2 fills all other guns except the Huben's, and you can fill the Huben's with a tank, is it possible the GX CS2 Quick Connect is not fully seated with the Huben fill probe? Air could be leaking from it.

 

[wgd]

I have a GX E-L2 battery version of the CS2. It fills my GK1 to 300 bar, and other non-Huben guns perfectly fine.

Since the CS2 fills all other guns except the Huben's, and you can fill the Huben's with a tank, is it possible the GX CS2 Quick Connect is not fully seated with the Huben fill probe? Air could be leaking from it.

Ya I am very careful about that seeding, it doesn't seem like its the problem, I'll try again. I was told that on my K1 a the check valve could be stuck and I need to depressurize the gun down below 15 MPa, then try compressor. But suddenly I cant fill either GK1 and they were not a problem for the last few months.

 

[Bernie7]

MrP,
I'm using the adaptor supplied by Huben. I bought both my GK1s in Spain. In point of fact cockeyed adaptor mounts is actually quite common and it is usually NOT the moderator that causes this. Take FX rifles as an example. The moderator attaches to an adaptor that screws into the shroud. I have not had an issue with mine, but others have. It is a really good idea to own a test rod that can be inserted through the mounted moderator and slip into the barrel. Very simple. The end of the rod should be a close fit to the land diameter of the barrel at barrel exit for a length of about 2". It should be long enough to extend beyond the end of the moderator. Then when placed through the mod and into the barrel and then viewing the rod exit on the mod, if everything is correct, the rod should be in the center of the mod bore. It is easy to see if it is not. This test rod delivers peace of mind and prevents damage.

I know they are not for sale anywhere that I am aware of. I suppose I could make some, if anyone is interested. They would not be expensive to make. The only tricky part would be knowing the exact land diameter of the barrel, so that diameter would have to be supplied to me. Please also note many guns have chokes, so it is important to get that number right. The easiest way is to use pin gauges as go/no go gauges. If you don't have any, go see your local machinist. It only takes a minute to test. It is best to use aluminum as it is softer than the steel of the barrel and will do no damage to either the barrel or the crown.

I have pin gauges ranging from .244 to .254, I could try to fetch this data once I’m back from Cali. I’m assuming .001” increments would be sufficient precision.

 

[JDGriz]

I found one possible design downside: I the cylinder is the highest point on each side. All knocks to the side, for example if the pistol is dropped, land on an individual cylinder chamber and are potentially squishing it a little (making it less perfectly round).

It's easy to fix in the right side with layers of ductape on my aftermarket loading gate. The left side would need a much higher/wider cylinder lever, possible even with a shape that follows the curvature of the cylinder.

 

[Airgun-hobbyist]

Fixing some pellet clipping because the shroud and barrel nut shift to misalign the moderator...

After discovering the clipping (shooting into gell) I used a 0.247" diameter carbon arrow shaft for the test rod to see where the misalignment was from. Unshrouded, the bare barrel, nut and moderator were perfectly aligned. Then I checked and rechecked the shroud. It appears the internal shoulder that the nut tensions onto was machined slightly offset, down in my case.

I wrapped one layer of clear box tape around the outside of the nut, and then glued a piece of wet/dry sandpaper to the very end, trimmed flush. Hand rotated, using the moderator on the nut with a little upward pressure to offset the sanding to the high side, it removed just enough of the metal (similar to a crescent moon, shiny in the picture) in the base shoulder to cock it back straight inline. I only removed about .005" to make it straight, measuring and re-testing often.

 

[Bernie7]

I have pin gauges ranging from .244 to .254, I could try to fetch this data once I’m back from Cali. I’m assuming .001” increments would be sufficient precision.

Ah! This is where the question originated. Incase anyone is wondering (I shared the info with @steve-l already in another thread) the muzzle end of the barrel is .247 go, .248 no go.

 

[Airgun-hobbyist]

Ah! This is where the question originated. Incase anyone is wondering (I shared the info with @steve-l already in another thread) the muzzle end of the barrel is .247 go, .248 no go.

The small diameter carbon arrows work great for this. Perfect fit, and these particular shafts have a 0.001" straitness over the total length. There's no doubts about alignment at the end of the moderator with one of these shoved up to the magazine.

 

[steve-l]

I have made another moderator and two barrel alignment gauge rods one in .22 and another in .25 along with a Band-Aid washer which is slightly smaller than the OD of the adaptor. This washer is .003" thinner on one side than the opposite side. The low side has a witness mark to identify it. If moderator skew is present, identified by the gauge rod, the washer can be rotated to counter the skew. This is not a permanent fix of course, but it will allow a third party validation of the design fault I identified earlier. It will also hopefully allow an unbiased assessment of the effectiveness of my moderator design. This package I will send to the HUBEN Gun Shop in Barcelona, Spain where I purchased both of my GK1s. We will see. . . . . . .

 

[JDGriz]

I have just discovered a design fault with the moderator adaptor. It functions as a shroud clamp and a mount point for a moderator and it is not possible to do that and maintain barrel to moderator bore alignment.

I spent some time checking moderator alignment and I found out that mine is tilted downwards with a slope of 1mm downwards shift to every 100mm length. The shroud has a cylindrical cutout for the adapter which is 15mm deep. The bottom edges of this cut is what the adapter rests on and depends on to be parallel to the shroud (and from there to the bore). The bottom edge of this cutout on my shroud is 15.16mm deep, and the top edge is 14.99mm deep, measured from the the front surface of the shroud. So basically the adapter itself is pointing downwards when tightened.
I think this might be due to tightening itself; I wish I could say "over-tightening", but I never tightened this too much. The top head-spacing edge is a step in the material of the shroud, and the bottom edge is a thin wall because there is a cutout directly behind it. I think the bottom edge might be bending backwards when the adapter is tightened. Alternatively, this might be due to repeated muzzle flip, and the weight of the supressor puting forces in that area.
(assuming the shroud doesn't come of the factory this way)

On a related note - the back of the shroud need to be made rest on something wedge-shaped on the front of the receiver; it doesn't have a consistent well supported position back there.

 

[JDGriz]

Fixing some pellet clipping because the shroud and barrel nut shift to misalign the moderator...

After discovering the clipping (shooting into gell) I used a 0.247" diameter carbon arrow shaft for the test rod to see where the misalignment was from. Unshrouded, the bare barrel, nut and moderator were perfectly aligned. Then I checked and rechecked the shroud. It appears the internal shoulder that the nut tensions onto was machined slightly offset, down in my case.

I wrapped one layer of clear box tape around the outside of the nut, and then glued a piece of wet/dry sandpaper to the very end, trimmed flush. Hand rotated, using the moderator on the nut with a little upward pressure to offset the sanding to the high side, it removed just enough of the metal (similar to a crescent moon, shiny in the picture) in the base shoulder to cock it back straight inline. I only removed about .005" to make it straight, measuring and re-testing often.

Mine is/was pointing downwards too. If you sand enough, the front surface of the shroud might become the higher surface (as the adapter is recessed further down into the shroud), and then the back surface of the moderator just rests on the front surface of the shroud, assuming the specific moderator has a wide flat surface on the back.

I super-glued a sandwich of two 13х19х0.2mm shim washers with a quarter piece of another 0.1mm shim washer in between. Then super-glued this on the shoulder, with the thicker part pointing down. Having said this, your solution is probably better.

 

[steve-l]

I spent some time checking moderator alignment and I found out that mine is tilted downwards with a slope of 1mm downwards shift to every 100mm length. The shroud has a cylindrical cutout for the adapter which is 15mm deep. The bottom edges of this cut is what the adapter rests on and depends on to be parallel to the shroud (and from there to the bore). The bottom edge of this cutout on my shroud is 15.16mm deep, and the top edge is 14.99mm deep, measured from the the front surface of the shroud. So basically the adapter itself is pointing downwards when tightened.
I think this might be due to tightening itself; I wish I could say "over-tightening", but I never tightened this too much. The top head-spacing edge is a step in the material of the shroud, and the bottom edge is a thin wall because there is a cutout directly behind it. I think the bottom edge might be bending backwards when the adapter is tightened.

On a related note - the shroud itself need to be made rest on something wedge-shaped on the front of the receiver; it doesn't have a consistent well supported position back there.

Yes, it is correct that the adapter can cant out of line with the barrel. This occurs because there must be running clearance in all threads and the adapter is asked to clamp the shroud to the receiver and maintain perfect alignment to the barrel. If everything is as it should be, it would work fine, but in the real world there will always be manufacturing tolerances. In this case the shroud is boss. If any surface on the shroud is not perfect the adapter will follow the error and force the adapter out of barrel alignment. This barrel misalignment can cause clipping IF the moderator bore has a close to barrel bore diameter and is not short. Additionally, I have noticed that the adapter when mounted is not always slightly proud of the front of the shroud. This is necessary to assure the moderator references the adapter's reference surface when tightening the moderator to the adaptor. If the adaptor's reference surface is not proud of the shroud, the shroud will become the reference surface.

The best way to check if you have a clipping issue before doing moderator damage is to use a test rod machined at the barrel end to the barrel land diameter. When placed through the mouth of the mounted moderator into the barrel. The rod should then exit the moderator with an even gap all around the exit hole of the moderator.

 

[JDGriz]

Yes, it is correct that the adapter can cant out of line with the barrel. This occurs because there must be running clearance in all threads and the adapter is asked to clamp the shroud to the receiver and maintain perfect alignment to the barrel. If everything is as it should be, it would work fine, but in the real world there will always be manufacturing tolerances. In this case the shroud is boss. If any surface on the shroud is not perfect the adapter will follow the error and force the adapter out of barrel alignment. This barrel misalignment can cause clipping IF the moderator bore has a close to barrel bore diameter and is not short. Additionally, I have noticed that the adapter when mounted is not always slightly proud of the front of the shroud. This is necessary to assure the moderator references the adapter's reference surface when tightening the moderator to the adaptor. If the adaptor's reference surface is not proud of the shroud, the shroud will become the reference surface.

The best way to check if you have a clipping issue before doing moderator damage is to use a test rod machined at the barrel end to the barrel land diameter. When placed through the mouth of the mounted moderator into the barrel. The rod should then exit the moderator with an even gap all around the exit hole of the moderator.

Threads surfaces are never used for alignment though, because yes - tolerances are always needed. The problem is that the actual alignment surface (the shoulder ring surface which is 15mm deep in the shroud) is too small/narrow and too crushable. Ideally it would be part of the barrel and not part of the shroud, but this could also do as it is, if it was larger.

 

[SenseiSmash]

Anyone deal with a leak on here? I just pulled my GK1 out and it was completely empty filled her back up and I have a constant leak coming out of the fill port.
Any suggestions on what could be the culprit or how to address?
Thank you in advance