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

I've shot literally thousands of 25.39 grain JSB and JTS pellets through my V3 GK1 at 870-880fps without a single malfunction.
It'll stack the JTS pellets at 35yds. I fill to 300 and shoot to 150.....over two magazines worth.
I'm amazed at the problems some of you are having.
If you'd shoot the correct grain pellets instead of slugs and fill to no more than 300bar and don't shoot below 150bar you will not have problems.
This has been discussed many times on this forum.
These are absolutely amazing guns, but like anything, they have their design limits.
Common sense helps

Oh, and one more thing....there is no "tuning" with a GK1.
You can adjust the FPS with a single screw adjustment, but there is no regulator to "tune" to like a regulated gun.
 
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On this gun, the tune encompasses fill pressure, pellet selection and velocity adjustment. I have both a Version 1 and a Version 3. I prefer the V1 over the V3. Simply because I'm right handed. That spring appears to be the same with both versions I have shot more than 10,000 pellets with no issues other than the before mentioned shroud/barrel alignment issue.
 
On this gun, the tune encompasses fill pressure, pellet selection and velocity adjustment. I have both a Version 1 and a Version 3. I prefer the V1 over the V3. Simply because I'm right handed. That spring appears to be the same with both versions I have shot more than 10,000 pellets with no issues other than the before mentioned shroud/barrel alignment issue.
Fill pressure has nothing to do with tuning on these guns.
Pellet selection is "pellet selection".
 
Yo tampoco he tenido ningún problema ni con la v1 22 ni con la v3 25 y disparo todos los días, la curva plana en la v3 cal 25 con JTS 25.39 es sobre los 865 desde 310 bar o más hasta 165 bares más o menos , son increíbles ambas y la máxima precisión en la 25 lo consigo con los JTS de 25.39 y con los King Heavy MK2 a 40 metros prácticamente en 1 solo hoyo.
 
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When I say tune I do just mean the screw for velocity, I am aware there is no regulator. I am also not aware of any claim that these are not supposed to shoot slugs. The k1s shoot slugs just fine and these have many similar or identical design features, I'd have to assume the possibility of people using slugs was something huben was aware of and planned for. I realize that at pistol ranges the BC difference between a pellet and slug will not be great, but slugs are still heavier and therfore make more energy. Also, I make my own ammo so for me, shooting slugs is cheaper than buying skirted pellets. I have personally always had better performance in terms of avoiding jams when using slugs on my k1s than using pellets.

When my spring bent, I was getting velocities of 850+ fps, but with 46-50 grain slugs, and filling to 5000 psi. Obviously that means my power was turned up more than it would be to achieve similar velocities with a pellet of half the weight.

I'm Inclined to agree that a stiffer spring with a guide inside it should help greatly, and would be a good change regardless what power and pressure you use your gk1 with
 
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When I say tune I do just mean the screw for velocity, I am aware there is no regulator. I am also not aware of any claim that these are not supposed to shoot slugs. The k1s shott slugs just fine and these have many similar or identical design features, I'd have to assume the possibility of people using slugs was something huben was aware of. I realize that at pistol ranges the BC difference between a pellet and slug will not be great, but slugs are still heavier and therfore make more energy. Also I make my own ammo so for me, shooting slugs is cheaper than buying skirted pellets

When my spring bent, I was getting velocities of 850+ fps, but with 46-50 grain slugs, and filling to 5000 psi. Obviously that means my power was turned up more than it would be to achieve similar velocities with a pellet of half the weight.

I'm Inclined to agree that a stiffer spring with a guide inside it should help greatly, and would be a good change regardless what power and pressure you use your gk1 with
Here's why I mentioned common sense.
 
When I say tune I do just mean the screw for velocity, I am aware there is no regulator. I am also not aware of any claim that these are not supposed to shoot slugs. The k1s shoot slugs just fine and these have many similar or identical design features, I'd have to assume the possibility of people using slugs was something huben was aware of and planned for. I realize that at pistol ranges the BC difference between a pellet and slug will not be great, but slugs are still heavier and therfore make more energy. Also, I make my own ammo so for me, shooting slugs is cheaper than buying skirted pellets. I have personally always had better performance in terms of avoiding jams when using slugs on my k1s than using pellets.

When my spring bent, I was getting velocities of 850+ fps, but with 46-50 grain slugs, and filling to 5000 psi. Obviously that means my power was turned up more than it would be to achieve similar velocities with a pellet of half the weight.

I'm Inclined to agree that a stiffer spring with a guide inside it should help greatly, and would be a good change regardless what power and pressure you use your gk1 with
Perhaps you know something I do not. It is my understanding that the magazines are the same in both the GK1 and the the K1. Please let me know the difference as you own a K1. You made the statement that the K1 shoots slugs well. if so how is the slug retained in the magazine?
 
Perhaps you know something I do not. It is my understanding that the magazines are the same in both the GK1 and the the K1. Please let me know the difference as you own a K1. You made the statement that the K1 shoots slugs well. if so how is the slug retained in the magazine?
Why try to shoot slugs in a gun that is not made for slugs?
Why try to shoot slugs when pellets are proven in the gun and super accurate?
Honest questions……I truly don’t get it.
 
Who is saying it isn't made for slugs? The reasons I don't use pellets is that I make slugs as mentioned so it's cheaper for me, and slugs are heavier and therfore hit harder. BC isn't much of an issue at pistol range, but I have shot it at 100 yard targets and not getting blown by the wind as much and better BC are advantages.

Anyway, here's a Pic of the k1 (mine is a 2021 model so can be certain there aren't minor differences with other years, they do alter these as time goes on) and my gk1 in .25, I have the 5th one made
1000010624.jpg
1000010630.jpg
 
Why try to shoot slugs in a gun that is not made for slugs?
Why try to shoot slugs when pellets are proven in the gun and super accurate?
Honest questions……I truly don’t get it.
Why is the GK1 not suitable for slugs? There's no prohibition of using them in the booklet. Nor is there a weight limit. Huben makes the Peanut slug at 33 grains. As long as it fits properly and shoots well, why not? There's people shooting heavier slugs than I do. Of course the slug has to be the correct size for your gun. You can't take an arbitrary slug and use it. You need to "slug" your gun to find out what size your gun likes. Or you can spend lots of cash randomly trying things, it's your choice.

I shoot NOE BBT 0.22 cal 28gr hollow point slugs that I cast. They are cheaper for me to cast than to buy pellets. Of course, I'm not counting my time. Fortunately they work well with my GK1. Yours may differ, so you need to slug it to see what size to use, and perhaps what style. (Drive bands.)

Find casting to be enjoyable. The outlay is not too great for casting gear, and it makes for a pleasant afternoon of casting, and anticipation of shooting my GK1. A leisurely afternoon will get me about 500 or so within 28.4 grains plus or minus 0.1 grains. I also cast 17gr wad cutters. Comparatively speaking, the slugs are a whole lot easier to cast, as the slug yields are far greater than for the flyweight wad cutters. It's hard to keep the mold hot for the smaller weight pellets. All the rejects go back in the pot. If I shoot into my rubber mulch trap, the recovered cast projectiles can all be recycled.
PXL_20240918_010627202.jpg
 
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Please note Asher's photos, there are no rifling grooves to retain slugs in the K1's magazine. The method for pellet retention in the mag is the light chamfer in the rear of the mags bores. This chamfer capturers the pellet skirt, which is always slightly larger in diameter than the pellet head. Get your caliper out and measure this fact yourself if you don't believe me. Slugs have no skirt and without this slightly oversize skirt there is no way to retain the slug except for bore resistance. The rub here is it is very difficult to get the correct slug diameter that provides just the right amount of resistance to prevent the slug slipping forward and jamming the gun. So for sb327, Asher, and WobblyHand, these guns are not designed for slugs without skirts and I know of no slugs that have a skirt.
 
There are rifling grooves in both. I can see it in both pics, I'm sorry if you can't. My previous phone had a macro camera, this one does not. In both of them, I have found .254 slugs to work best, and they're both sufficiently snug as to not slip. When jams occur with the slug between the barrel and mag, it's almost always a spring issue, and that goes for both the k1 and gk1

Furthermore, I had a swage die that made slugs that were a bit too rounded and not pointy enough. When making them long enough to fill the slot (which seems to give me better accuracy than when they're shorter, and makes sure theyre all seated the same so transition from mag to barrel is always the same), they engaged with too much of the rifling, making them difficult to seat without a tool to push them. When I had a new swage die made, I sent corbin 10 slugs which had been seated, then removed so they could see where the rifling marks started and make a slug with an o give just pointy enough to avoid hitting the rifling until further back where the bearing surface begins. So I assure you, there are rifling grooves in the mag slots
 
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Please note Asher's photos, there are no rifling grooves to retain slugs in the K1's magazine. The method for pellet retention in the mag is the light chamfer in the rear of the mags bores. This chamfer capturers the pellet skirt, which is always slightly larger in diameter than the pellet head. Get your caliper out and measure this fact yourself if you don't believe me. Slugs have no skirt and without this slightly oversize skirt there is no way to retain the slug except for bore resistance. The rub here is it is very difficult to get the correct slug diameter that provides just the right amount of resistance to prevent the slug slipping forward and jamming the gun. So for sb327, Asher, and WobblyHand, these guns are not designed for slugs without skirts and I know of no slugs that have a skirt.
Not sure what your problem is but the magazines do in fact have lands in them. I can see them in the picture. Of course they are subtle because they are designed to hold a projectile with the least amount of deformation to the lead.

I also gave a link to slugs that are Huben branded specifically for the huben guns.

Below is from the picture posted above, I magnified the mag and screen shot it.

Dave


IMG_6271.jpeg
 
Apparently the newer k1s even have 12 groove rifled mag where the barrel is 6 groove. I had Kelly replace my mag on my 2024 k1 with a 2018 mag (from back when they were also 6 groove), and it made a huge difference in shooting slugs and pellets. I shoot 36gr flat base AVS slugs in my K1, and 28gr flat base VK or AVS slugs in my GK1. Both in .22.
.2193 for the k1
.223 for the gk1

The slugs for those guns fit into the mag just snug like a pellet does. The k1 2024 mag was so large tho, even .223 slugs were falling through. I don't know what happened there.