Huben .25 GK1 V3

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zx10wall

zx10wall

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Apr 3, 2015
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Took delivery of a .25 GK1. Tuned it for a mag (17 rounds) on a fill. Settled on 310 bar fill which produces great results. This is my second GK1 and I’ve come to see these pistols are absolutely crazy good. I’ll be trying the 25.39gr Kings, 33.95gr King Heavies and the 29.32 JTS Semi-Dom pellets. Here’s the string with the 25.39gr:

Created: 01/13/24 11:40 AM
Description: .25 Huben GK1
Notes 1: 12023B00763
Notes 2: 310 bar fill
Distance to Chrono(FT): 1.50
Ballistic Coefficient: 0.038
Bullet Weight(gr): 25.39
Temp: N/A °F
BP: N/A inHg
Altitude: 150.00
# FPS FT-LBS PF
17 875 43.17 22.22
16 879 43.57 22.32
15 881 43.77 22.37
14 885 44.16 22.47
13 883 43.96 22.42
12 879 43.57 22.32
11 887 44.36 22.52
10 888 44.46 22.55
9 875 43.17 22.22
8 880 43.67 22.34
7 883 43.96 22.42
6 889 44.56 22.57
5 883 43.96 22.42
4 883 43.96 22.42
3 881 43.77 22.37
2 893 44.97 22.67
1 893 44.97 22.67
Average: 883.4 FPS
SD: 5.3 FPS
Min: 875 FPS
Max: 893 FPS
Spread: 18 FPS
Shot/sec: 0.1
True MV: 886 FPS

👆🏻Awesome baby!!!
 
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Same tune with 33.95gr King Heavies:

Created: 01/13/24 12:28 PM
Description: .25 Huben GK1
Notes 1: 12023B00763
Notes 2: 330 bar fill
Distance to Chrono(FT): 1.50
Ballistic Coefficient: 0.055
Bullet Weight(gr): 33.95
Temp: N/A °F
BP: N/A inHg
Altitude: 150.00
# FPS FT-LBS PF
17 799 48.13 27.13
16 804 48.74 27.30
15 810 49.47 27.50
14 821 50.82 27.87
13 809 49.35 27.47
12 812 49.71 27.57
11 808 49.22 27.43
10 812 49.71 27.57
9 810 49.47 27.50
8 813 49.84 27.60
7 814 49.96 27.64
6 817 50.33 27.74
5 812 49.71 27.57
4 817 50.33 27.74
3 821 50.82 27.87
2 823 51.07 27.94
1 825 51.32 28.01
Average: 813.4 FPS
SD: 6.8 FPS
Min: 799 FPS
Max: 825 FPS
Spread: 26 FPS
Shot/sec: 0.1
True MV: 815 FPS

JTS 29.32 grainers will deliver Monday. I’ll then get to accuracy testing. Stay tuned y’all‼️Astonishing performance so far 😆
 
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zx10wall said:
Took delivery of a .25 GK1. Tuned it for a mag (17 rounds) on a fill. Settled on 310 bar fill which produces great results. This is my second GK1 and I’ve come to see these pistols are absolutely crazy good. I’ll be trying the 25.39gr Kings, 33.95gr King Heavies and the 29.32 JTS Semi-Dom pellets. Here’s the string with the 25.39gr:

Created: 01/13/24 11:40 AM
Description: .25 Huben GK1
Notes 1: 12023B00763
Notes 2: 310 bar fill
Distance to Chrono(FT): 1.50
Ballistic Coefficient: 0.038
Bullet Weight(gr): 25.39
Temp: N/A °F
BP: N/A inHg
Altitude: 150.00
# FPS FT-LBS PF
17 875 43.17 22.22
16 879 43.57 22.32
15 881 43.77 22.37
14 885 44.16 22.47
13 883 43.96 22.42
12 879 43.57 22.32
11 887 44.36 22.52
10 888 44.46 22.55
9 875 43.17 22.22
8 880 43.67 22.34
7 883 43.96 22.42
6 889 44.56 22.57
5 883 43.96 22.42
4 883 43.96 22.42
3 881 43.77 22.37
2 893 44.97 22.67
1 893 44.97 22.67
Average: 883.4 FPS
SD: 5.3 FPS
Min: 875 FPS
Max: 893 FPS
Spread: 18 FPS
Shot/sec: 0.1
True MV: 886 FPS

👆🏻Awesome baby!!!
Click to expand...
Have you tried continuing with a 2d mag before refilling? I am curios to know if you can get a decent series of shots thru 2 magazines? Were the heavier JSB's shooting just as accurate with that same tune?
 
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RIshooter said:
Great job and great info guys.
I'm curious to know how these numbers correlate to POI though.
Is there a noticeable difference?
Those numbers look extremely consistent so I would imagine that equates to accuracy, correct?
Click to expand...
At 30 yards and in a 25 fps is hard to detect as far as accuracy / POI dispersion. At 50 yards you can see POI changes from a 25 fps difference but not much.
 
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primaz said:
Have you tried continuing with a 2d mag before refilling? I am curios to know if you can get a decent series of shots thru 2 magazines? Were the heavier JSB's shooting just as accurate with that same tune?
Click to expand...
I tuned for one mag. Once you get past 17 shots with my tune, the speed begins falling fast. Accuracy testing is coming next week.
 
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It's pretty loud, and I have my .22 tuned for only 14ftlbs. I don't need quiet where I live, but I purchased the Huben kit with factory moderator anyway, from Kelly. The small size blends in nicely with the shroud. And it is very quiet, which makes for a nice peaceful shooting session, while woods walking.
I highly recommend that moderator.
Have fun!
 
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For comparison sake, and why I chose a .22 caliber GK1.

My compressor being capable of only 250 BAR, that translates to only 230 BAR on my GK1's gauge. So I hoped to find a tune (power level) with 18.1s that would return a full magazine number of shots (19) with a bell-curve within about 40 FPS extreme spread. It took a LOT of doing to get there, but I did get close (40-50 FPS ES). From my notes-

18.1 grain FX (JSBs), 230 BAR on gun gauge, 19 shot powerband- Low= 842, Hi= 887, ES= 45, SD= 14, Avg= 863 FPS/ 30.0 foot pounds.

Having achieved my goal with 18.1s, I then tested it with 21.53 grain JTS pellets (that were included in the gypping I took from the crook that sold me my DW-tuned .22 GK1, who now not only has a .25 GK1, but is challenging me to a hundred-yard field target duel!). My notes-

21.53 grain JTS, 230 BAR, 19 shot powerband- 791/850/59/14/827.

However, losing the last 4 shots that were falling in velocity, the powerband looks like this- 15 shot powerband- 821/850/29/10/834/33.3 foot pounds.

Another reason I chose .22 is because I intend to shoot many thousands of rounds through this semi-auto wonderment of air pistol engineering, quality and previously-unheard-of PERFORMANCE; so (eventually) ammo-expense savings might fund a compressor capable of charging a GK1 to charge levels similar to that of the crook's that gypped me so badly!:ROFLMAO:

1705257525995.png


Mine's prettier! And that Huma Mini 30 moderator is the best fit for this surprisingly small and light super magnum semi-auto air pistol.

BTW- in tuning it, at one point I saw 1019 FPS with 18.1s (41.7 foot pounds)! :oops::eek:

Also- GOOD SHOW, DW! ;)

.
 
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zx10wall said:
His concerns are not in vein. It needs a moderator for sure.
Click to expand...

This is a great thread on how to tame the sound of the GK1, there are some highly skilled forum members whom have designed great moderators that they will 3D print for you! They are much less costly, more effective, smaller and better style that than traditional options. I highly recommend you check this thread out!

Huben - GK1 - taming the bark

This is a fork of the main Huben GK1 thread intended to provide further discussion related to taming the rather loud bark of this incredible pistol. Mod adapters have been provided by Ares, Kelly@KrazCool and now Huben themselves. I have tested a wide range of commercially available mods and...
www.airgunnation.com www.airgunnation.com
 
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