Published on April 20, 2024
The GK1... Wow, what a gun! There are already tons of videos about it on YouTube. But: Be careful... There’s also a lot of misinformation out there. The number one tip you should follow as an owner: Read the manual very, very carefully. And yes, I know this from experience 
Don't make the classic mistake of immediately setting everything to maximum power, stuffingslugs the heaviest or lightestslugs , and then starting to shoot. You're sure to run into trouble that way. If you experience a jam or an airdump, one thing is certain:
Your power setting/ammo choice isn't optimal. Fix that!
A few more comments:
Is it regulated? Yes and no, or no and yes. No: It doesn’t have a pneumatic regulator. Yes, you can adjust the speeds using the power screw and thus regulate it. You can even achieve a reasonably nice bell curve that way. Of course, you’ll need a reliable chronometer.
When using pellets, we recommend a starting adjustment of 1.25 turns counterclockwise from the closed position. Push the pellets into the magazine with your thumb until the edge of the skirt is flush with the magazine. Avoid using a ballpoint pen or similar object to push them in, as this may cause you to push the pellet in too far, allowing it to shift inside the magazine. This means you’ve sized it too small.
With slugs , pay slugs close attention to the fit in the magazine. For Huben, you need an oversized slug. If the slug just falls into the magazine on its own, the fit is much too loose. It needs to fit snugly. Again, the back should be flush and, ideally, meet some resistance as it enters the magazine. Powerstand: Start above 1.25 rotations and adjust in 1/4-turn increments counterclockwise. Don’t go straight to the maximum (which is only about 3 full turns). Build it up gradually until you achieve a fine adjustment.
Never let the pressure drop below 120 bar! The pressure gauge is conveniently located, so keep a close eye on it at first until you gain more experience. That way, you’ll know how many shots you can get out of a single fill.
The GK1 can be filled to 350 bar. The thing is, most people have a 300-bar tank. You can use the pump to top it off to 350 bar. That’s pretty hard work, and you have to let the pump cool down in between. In addition to being in good physical condition, you also need to master the technique.
So is it a problem if you shoot at a lower pressure? No, not at all. You’ll have slightly less peak power and a slightly lower “shot count.” But: That’s no big deal. However: Just make sure you don’t drop below 120 bar while you’re having fun shooting.
If you experience an airdump, there’s no need to worry. If you can no longer operate the safety catch, you’ll need to reset the gun. Refer to the manual for instructions on how to do this. Always be careful and make sure your gun is pointed in a safe direction when you’re loading it!