Here is an other spin off thread for the Huben pistol where members can share what ammo they have found works good,....... or bad in their hand cannon.
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Huben Huben pistol ammo choice.
- Thread starter Nomadic Pirate 66
- Start date
Here are the 6 shots with AVS 22grain in that sweet spot of the string. I was forced to go 8 yards further due to annoying December sun angle. Aside from that, the weather is great here in Utah and I’m going for a hike after this! I did replace my sticker this time 
The results are really good:
The circle is 0.75 so I estimate a CTC of 0.6. That’s within spitting distance of GTO performance so I’m glad that I focused on exploring the string dynamics. Of course, it’s one 6 shot group but I’ll now sight these in properly and use them for a while. If Dale@VK could post here, it would be good for him and us. Aside from that, I’ve had fun on this slug tear and I hope that this thread can become more like this, with real testing and posting of data, rather than fighting and conjecture. It is after all named as the ammo thread and I take that to indicate its utility in guiding choice of ammo. Have a good day gents (or night, considering Euro friends) and a special thanks to @wimpanzee for the productive interactions.
The results are really good:
The circle is 0.75 so I estimate a CTC of 0.6. That’s within spitting distance of GTO performance so I’m glad that I focused on exploring the string dynamics. Of course, it’s one 6 shot group but I’ll now sight these in properly and use them for a while. If Dale@VK could post here, it would be good for him and us. Aside from that, I’ve had fun on this slug tear and I hope that this thread can become more like this, with real testing and posting of data, rather than fighting and conjecture. It is after all named as the ammo thread and I take that to indicate its utility in guiding choice of ammo. Have a good day gents (or night, considering Euro friends) and a special thanks to @wimpanzee for the productive interactions.
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I only tested once when I first got it, before it got set to very low power. The results with 50gr were:
fps - bar - fpe
891 - 350 - 88
868 - 330 - 84
848 - 310 - 80
828 - 290 - 76
798 - 265 - 71
770 - 240 - 66
753 - 225 - 63
x - 205
I stopped before I saw a flat portion, because I thought the speed was getting too low anyway- but there probably isn't one, at this power level.
This matches closely with the effective fpe results in this video (with 44gr):
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Phew! Yes, based on that slope, the plateau of the power curve is well above your starting pressure.
Looking back at my strings and Wimpanzees data, I get the sense that the power curves from this unregulated hammerless system are not like those of conventional unregulated PCPs, which is not a shocker. I’d like to see more data, preferably strings from as high a starting pressure as possible, with projectiles that are not so large as to generate a Korean cliff. I think we could all benefit from a better understanding of these dynamics. I will do what I can, but have 7 guns to fix and tune to help a certain overwhelmed local enterprise.
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FYI ammo cycling issues:
The Seneca .25 Cal, 43.2 Grain pointed pellet is a touch too long to fit into the magazine and cycle. These are Eun Jin 43.2 grain pellets. I pound the point flat on a metal table and they cycle. Once I've gone through these tins I'll not buy them again.
The H&N Baracuda .25 Cal, 30.86 Grain Long range hunting round nose pellets are loose fitting in the magazine and with the longer pointed head they will work, but they do ride forward enough to cause a bit of jamming. I bump the back of the grip and they fall backward to cycle properly.
The Seneca .25 Cal, 43.2 Grain pointed pellet is a touch too long to fit into the magazine and cycle. These are Eun Jin 43.2 grain pellets. I pound the point flat on a metal table and they cycle. Once I've gone through these tins I'll not buy them again.
The H&N Baracuda .25 Cal, 30.86 Grain Long range hunting round nose pellets are loose fitting in the magazine and with the longer pointed head they will work, but they do ride forward enough to cause a bit of jamming. I bump the back of the grip and they fall backward to cycle properly.
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At the power levels I am shooting at, I get a decent string.
Today I started at 350 bar, with the 28.5gr VK, and started at 770fps. It went up to 812, and ended the first mag there, at around 200 bar. I was refilling at that point, because I wanted to shoot full mags. I am not sure how far up it would go at that setting, but likely rise higher before dropping down.
Shot these targets at 25 yards with a green dot - black circle is 2 inches...:
Today I started at 350 bar, with the 28.5gr VK, and started at 770fps. It went up to 812, and ended the first mag there, at around 200 bar. I was refilling at that point, because I wanted to shoot full mags. I am not sure how far up it would go at that setting, but likely rise higher before dropping down.
Shot these targets at 25 yards with a green dot - black circle is 2 inches...:
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After having some fun with those AVS slugs, I decided to tune the GK1 back down to shoot GTOs at 900fps. I use the pistol for pesting in my yard mostly at 30y or less, so I prefer lower power and flat shooting out to 40. After using a scope, I couldn’t go back to a red dot, so it now has a Bugbuster, awaiting delivery of something nicer. Also, I opened up the holes in my air stripper mod that allows the shroud to be functional (to 1/8 inch holes) and it makes quite a difference. The GK1 is now very backyard friendly shooting the GTOs at 21fpe.
Now, after settling it in at 900fps, the grouping was not what I remembered, not even close, like 2-3moa! Cleaned the barrel and it came back on song, so it seems that they do not shoot well if you transition from shooting lead, or perhaps it was just that shooting slugs makes for a GTO-unfriendly barrel. Here’s what I got at 45yards. There’s a pretty calm shot cycle with these and I’m shooting from a rice bag, holding the airtube and pressing it back towards the grip. Yeah, I know, major cheating but this is what I’m finding to work for what I need to do.
5 shots. The squished lead pellet at the base was from my Katran and I missed plucking it out before starting. The missing GTO is a pellet on pellet - the leftmost one, which is why that hole is large.
Guys, this GK1 is a spectacular PCP, regardless of size. I have >20 PCPs and live near UA, so I’ve shot a lot more than that. Once you get a grip on it and work out where the flat regions of the shot string live, it will easily outshoot its bigger brother (the K1) and the Leshiy 2.
Here is the string for GTOs from 280-170bar, which, strangely, shows speed bumps at either end. Still, a wide range of pressure where it is very flat and I’m a one mag fill and reload guy:
Huben 22, GTO, retuned for 900fps at 230bar, 0.6turns down from AVS 22grain@890fps
Shot count: 33
Low: 893 FPS
Hi: 923 FPS
Avg: 904 FPS
Spread: 30 FPS
STD Dev: 8.6 FPS
19-Dec-2023 09:40:13,921,FPS,22.1,FT Lbs,
19-Dec-2023 09:40:24,921,FPS,22.1,FT Lbs,
19-Dec-2023 09:40:48,914,FPS,21.8,FT Lbs,
19-Dec-2023 09:40:54,907,FPS,21.5,FT Lbs,
19-Dec-2023 09:41:00,905,FPS,21.4,FT Lbs,
19-Dec-2023 09:41:20,905,FPS,21.4,FT Lbs,
19-Dec-2023 09:41:31,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:41:40,893,FPS,20.8,FT Lbs,
19-Dec-2023 09:41:48,905,FPS,21.4,FT Lbs,
19-Dec-2023 09:41:55,900,FPS,21.1,FT Lbs,
19-Dec-2023 09:42:06,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:42:13,898,FPS,21.0,FT Lbs,
19-Dec-2023 09:42:20,900,FPS,21.1,FT Lbs,
19-Dec-2023 09:42:24,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:42:29,893,FPS,20.8,FT Lbs,
19-Dec-2023 09:42:43,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:42:50,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:44:01,898,FPS,21.0,FT Lbs,
19-Dec-2023 09:46:40,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:46:48,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:46:55,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:01,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:06,900,FPS,21.1,FT Lbs,
19-Dec-2023 09:47:11,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:16,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:23,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:51:08,909,FPS,21.6,FT Lbs,
19-Dec-2023 09:51:14,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:51:20,909,FPS,21.6,FT Lbs,
19-Dec-2023 09:51:25,912,FPS,21.7,FT Lbs,
19-Dec-2023 09:51:33,912,FPS,21.7,FT Lbs,
19-Dec-2023 09:51:44,923,FPS,22.2,FT Lbs,
19-Dec-2023 09:51:53,923,FPS,22.2,FT Lbs,
So I’m now shooting my mag from 250bar to exploit that very flat region in the string at 893-900fps.
Now, after settling it in at 900fps, the grouping was not what I remembered, not even close, like 2-3moa! Cleaned the barrel and it came back on song, so it seems that they do not shoot well if you transition from shooting lead, or perhaps it was just that shooting slugs makes for a GTO-unfriendly barrel. Here’s what I got at 45yards. There’s a pretty calm shot cycle with these and I’m shooting from a rice bag, holding the airtube and pressing it back towards the grip. Yeah, I know, major cheating but this is what I’m finding to work for what I need to do.
5 shots. The squished lead pellet at the base was from my Katran and I missed plucking it out before starting. The missing GTO is a pellet on pellet - the leftmost one, which is why that hole is large.
Guys, this GK1 is a spectacular PCP, regardless of size. I have >20 PCPs and live near UA, so I’ve shot a lot more than that. Once you get a grip on it and work out where the flat regions of the shot string live, it will easily outshoot its bigger brother (the K1) and the Leshiy 2.
Here is the string for GTOs from 280-170bar, which, strangely, shows speed bumps at either end. Still, a wide range of pressure where it is very flat and I’m a one mag fill and reload guy:
Huben 22, GTO, retuned for 900fps at 230bar, 0.6turns down from AVS 22grain@890fps
Shot count: 33
Low: 893 FPS
Hi: 923 FPS
Avg: 904 FPS
Spread: 30 FPS
STD Dev: 8.6 FPS
19-Dec-2023 09:40:13,921,FPS,22.1,FT Lbs,
19-Dec-2023 09:40:24,921,FPS,22.1,FT Lbs,
19-Dec-2023 09:40:48,914,FPS,21.8,FT Lbs,
19-Dec-2023 09:40:54,907,FPS,21.5,FT Lbs,
19-Dec-2023 09:41:00,905,FPS,21.4,FT Lbs,
19-Dec-2023 09:41:20,905,FPS,21.4,FT Lbs,
19-Dec-2023 09:41:31,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:41:40,893,FPS,20.8,FT Lbs,
19-Dec-2023 09:41:48,905,FPS,21.4,FT Lbs,
19-Dec-2023 09:41:55,900,FPS,21.1,FT Lbs,
19-Dec-2023 09:42:06,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:42:13,898,FPS,21.0,FT Lbs,
19-Dec-2023 09:42:20,900,FPS,21.1,FT Lbs,
19-Dec-2023 09:42:24,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:42:29,893,FPS,20.8,FT Lbs,
19-Dec-2023 09:42:43,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:42:50,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:44:01,898,FPS,21.0,FT Lbs,
19-Dec-2023 09:46:40,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:46:48,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:46:55,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:01,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:06,900,FPS,21.1,FT Lbs,
19-Dec-2023 09:47:11,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:16,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:47:23,902,FPS,21.3,FT Lbs,
19-Dec-2023 09:51:08,909,FPS,21.6,FT Lbs,
19-Dec-2023 09:51:14,895,FPS,20.9,FT Lbs,
19-Dec-2023 09:51:20,909,FPS,21.6,FT Lbs,
19-Dec-2023 09:51:25,912,FPS,21.7,FT Lbs,
19-Dec-2023 09:51:33,912,FPS,21.7,FT Lbs,
19-Dec-2023 09:51:44,923,FPS,22.2,FT Lbs,
19-Dec-2023 09:51:53,923,FPS,22.2,FT Lbs,
So I’m now shooting my mag from 250bar to exploit that very flat region in the string at 893-900fps.
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min Europa no veo disponibles los GTO, hay estos que parecen lo mismo, si alguien lo puede aclarar?
Saludos.
Saludos.
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Has anyone confirmed that these Apollo .25 40 grain slugs fit well in the GK1?
Other than those it seems like others have said that the JSB Match Diablo Heavy .25 33.95 grain pellets shoot well and the NSA 38.5 grain .254 slugs also are a good slug. It is funny that the JSB if you buy the 150 tin it is 9.9 cents per pellet but if you buy the 300 tin it is 8.3 cents per pellet; the NSA 38.5 .254 hollow point slugs are 8.99 cents per slug. Thus the cost between pellets and slugs are very close, unless those Apollo slugs really fit well as those are only 5.3 cents per slug.
With the cost of pellets vs slugs being so close what is everyone's opinion on choice of ammo for the GK1?
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??? So what is your top 3 ammo choices for the GK1 ????, ideally for the .25 caliber GK1??
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I shoot a lot, so cost is a primary concern. It is nice to know that more energy is available, but I don't need that much to punch paper at 25 meters and cause non-lethal pain to thieves. My GK1 is set up for 700 fps with the 25 gr. pellet. In that light, The JSB 25 gr 25 cal pellet fits my bill well. A tin of these pellets cost the same as the 33.4 gr pellets, but instead of 300 pellets a tin contains 350. My cost then 4.7 Euro cents each.
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How many shots do you get with those 25 gr. pellets? Have you used the JSB 33.4 gr. pellets and if so what was the ideal FPS & the difference in shot count?
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D
Deleted member 25487
Guest
Without hijacking the thread just curious if anybody knows what the maximum slug length for the magazine is in .25cal?
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I'm not sure how to answer that question. Shots per tin is 350. I charge the gun to 300 bar, shoot 17 shots and recharge. After one magazine, I have 210 bar left in the tank. I also use the 33.4 pellets, but only for my Crown at the moment. They are slightly more expensive to shoot in the pistol and for my intended purposes, do not add usable value.
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I have one of the MP molds round nose/boat tail airgun slug molds in 25 caliber and a .25 gk1 on the way. I know that this mold was specifically made to work with the GK one magazine and barrel (before they switched to a lower twist rate pellet barrel in 2020/2021). Has anyone tried shooting these out of the pistol? I will be doing so myself eventually.
(I’d like to shoot these slugs because of the ease of casting compared to diabolo pellets - my 8 cavity mold really makes it easy to cranks these out).
(I’d like to shoot these slugs because of the ease of casting compared to diabolo pellets - my 8 cavity mold really makes it easy to cranks these out).
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New GK1 V2 .25 cal user issues
Ok - just got the GK1 this week from Ares (shipping issues, delayed a month), and it isn't going well. The GK1 doesn't seem to like the .25 FX Hybrid Slugs (a bit loose), and so I tried some ZAN .253 slugs and they seemed really tight.
The FX .25 went in ok but seemed a tad loose. They didn't fall through the magazine when the pistol was pointed down, but they would fall out easily if I tilted it back. Some of the slugs actually misfired and ended up in the last stage of the Impulse Air 1350 moderator. Never seen that before - glad it's modular and I could just unscrew it and remove them.
I could press the .253 ZANs in, and the magazine turned if I pushed them in so they were flush with the edge of the magazine, but they sometimes misfired as well, and/or left chunks of pellet in the Impulse Impulse Air 1350 moderator. There are really heavy rifling markings on the slugs - which means that the velocity and force is significantly impacted.
Neither of these scenarios can be right.
Are there off-the-shelf PELLETS that I should be using? My .30 cal Alpha Wolf doesn't seem as picky - though I don't plan to try slugs in it, and I'm not really locked into using slugs on the GK1. I HAVE read this entire thread, and thought the ZAN .253 slugs would be ok - though someone also mentioned that they were tight. I'm not wanting to get into anything custom - just something that works off the shelf?
Another question - is the Huben fill probe connection a weird size? I thought all the quick release connections were pretty much universal and were about the same - just some (like for my Alpha Wolf) require a longer one. The Huben fill probe won't connect in the longer quick release connection I use for my Alpha Wolf, but does connect in the shorter one that came with my pump hose.
Sorry for the relative newbie questions -
Larry Becker
Ok - just got the GK1 this week from Ares (shipping issues, delayed a month), and it isn't going well. The GK1 doesn't seem to like the .25 FX Hybrid Slugs (a bit loose), and so I tried some ZAN .253 slugs and they seemed really tight.
The FX .25 went in ok but seemed a tad loose. They didn't fall through the magazine when the pistol was pointed down, but they would fall out easily if I tilted it back. Some of the slugs actually misfired and ended up in the last stage of the Impulse Air 1350 moderator. Never seen that before - glad it's modular and I could just unscrew it and remove them.
I could press the .253 ZANs in, and the magazine turned if I pushed them in so they were flush with the edge of the magazine, but they sometimes misfired as well, and/or left chunks of pellet in the Impulse Impulse Air 1350 moderator. There are really heavy rifling markings on the slugs - which means that the velocity and force is significantly impacted.
Neither of these scenarios can be right.
Are there off-the-shelf PELLETS that I should be using? My .30 cal Alpha Wolf doesn't seem as picky - though I don't plan to try slugs in it, and I'm not really locked into using slugs on the GK1. I HAVE read this entire thread, and thought the ZAN .253 slugs would be ok - though someone also mentioned that they were tight. I'm not wanting to get into anything custom - just something that works off the shelf?
Another question - is the Huben fill probe connection a weird size? I thought all the quick release connections were pretty much universal and were about the same - just some (like for my Alpha Wolf) require a longer one. The Huben fill probe won't connect in the longer quick release connection I use for my Alpha Wolf, but does connect in the shorter one that came with my pump hose.
Sorry for the relative newbie questions -
Larry Becker
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Hi Larry,
Welcome to the club : )
Do you have the power turned up (twist the power wheel to the left) when firing the slugs? Out of the box my Huben was turned allll the way down.
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Hopefully the gun was set to low power and barely spat them out. If not and the slugs ended up in the moderator, the question becomes: where was their energy delivered?
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Well, I'm embarrassed to say that I didn't do any power adjustments. I wanted to make sure it worked "as is" - and it barely did. I thought that you had to take the handgrip off and "Unlock the potential" of it (per a video from Wolfeik Group's YT channel, but looking again at the video from Ares Airgun Tactical (where I got it), I see that it's a simple adjustment with the hex key. It's been almost a month and a half since I ordered it... shipping drama - I forgot all about that. Anyway, I installed the Speed Loader from Ares, as well as the Impulse Air 1350 moderator - and was worried I was getting some clipping on the moderator. I haven't read about issues with the 1350 and the GK1.
Tomorrow I'll up the power and put a chronograph on it. I'll report back when I've sorted it out...
EDIT: DOES ONE IN FACT HAVE TO "UNLOCK" THE GUN, REMOVING THE PLUG UNDER THE HANDLE?
Any input on other ammo for the GK1 .25?
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