Huben pistol.

[JDGriz]

This pistol has deceptively good design, as a pistol. But now that I have had it for a bit, I begin see the former rifle in it (I have never had the K1). Some of its quirks are not quirks in a rifle and it probably benefits enormously from having been a very accurate rifle.

 

[bluemoon_wulf]

My finished baby.
Although I would like to get my hands on an original immersive optics prism.

 

[Sergey1972]

My finished baby.
Although I would like to get my hands on an original immersive optics prism.


View attachment 409061

Looks great. The immersive optics may not be ideal with zero eye relief, wouldn't be able to shoot without stock.

 

[bluemoon_wulf]

Looks great. The immersive optics may not be ideal with zero eye relief, wouldn't be able to shoot without stock.

I am still learning to shoot decent. I do have a monstrum pistol scope that works cool as rifle or pistol.
But I am also practicing locking arms together and using left elbow as rest for pistol, so prism still usable that method.
I need enough trigger time outside my apartment to decide which pistol method hunts better for me. But otherwise Carbine is my first choice. My p-rod as bullpup was soooo much more accurate for me.

 

[JDGriz]

I'm beginning to think that the grip is unnecessarily wide. It looks pretty, but a 1911-shaped grip might be more ergonomic.

 

[steve-l]

The spring might also be catching on the edge of the hole in the metal part with the two screws. In which case increasing the inner diameter of the buffer would not help and might make things worse. If that's the case than the hole in the metal part might need a little bit of chamfer, but don't go chamfering metal parts just because I said it might.

It might, but I emphasize, you don't know. If it happens it means the spring is coming out of column. That can ONLY happen if it is coil stacking, which stresses the spring wire into distortion. So let's talk about preventing that.

 

[sb327]

This is correct. To deform/break this spring means it has went into a stack/bind situation.

Obviously this is caused by the added force due to higher operating pressure. Two things absorb this force, the spring and buffer rubber.

If the spring is beefier, it will stack sooner (if using larger diameter wire). The valve needs a certain amount of travel to operate obviously. This also means the buffer would absorb less of the energy.

If I start having issues (I have had one bent spring and now I don’t fill to max), I will probably add some washers, one at a time, made from rubber to the buffer side of the equation. I will add them to the cover side so they stay put. This should put more of the buffering load on the buffer and off the spring.

Dave

 

[steve-l]

This is correct. To deform/break this spring means it has went into a stack/bind situation.

Obviously this is caused by the added force due to higher operating pressure. Two things absorb this force, the spring and buffer rubber.

If the spring is beefier, it will stack sooner (if using larger diameter wire). The valve needs a certain amount of travel to operate obviously. This also means the buffer would absorb less of the energy.

If I start having issues (I have had one bent spring and now I don’t fill to max), I will probably add some washers, one at a time, made from rubber to the buffer side of the equation. I will add them to the cover side so they stay put. This should put more of the buffering load on the buffer and off the spring.

Dave

This is the kind of conversation needed to resolve issues like this. Thank you for your enlightenment. The real issue to resolve this is the lack of space. Our choices are a stop, a buffer or or a compound spring or perhaps a combination of those. I'm working on it. I have ordered new parts to establish a design base line. The list of questions to be answered first is below. There will be more questions of course, but these questions could hard parameters.
1) What is the minimum travel required?
2) What is the max travel possible of the valve?

 

[Nomadic Pirate 66]

Question:

So if you only fill to 250 BAR does this spring problem become nonexistent ?

 

[Nomadic Pirate 66]

I'm beginning to think that the grip is unnecessarily wide. It looks pretty, but a 1911-shaped grip might be more ergonomic.

I though the same and was planning to do so reshaping but after testing the pistol I found the grip very comfortable,...still going to do some reshaping but not as much as I was planning

 

[Pale_Rider]

Question:

So if you only fill to 250 BAR does this spring problem become nonexistent ?

Filling to 300 or even 350 bar alone won’t cause damage to the spring. It’s a combination of setting the power wheel to higher power(allowing more air to be released) AND having high fill pressures. I’ve been filling to 300 bar and having the power wheel set for low power and it has not damaged my spring.

I can see why huben originally posted the max power of this pistol as 40(+-) fpe for .25 and 30 fpe for .22. Of course they knew the pistol could produce much higher power but certain parts would not be able to withstand those forces. This is a good opportunity for someone to figure this out and offer a kit for those wanting to reliably shoot at higher power.

I agree with Steve’s hypothesis about spring stacking. I also agree with Dave’s statement that a beefier spring will reach max compression sooner. However, because it is beefier it will be harder to compress and might not reach full compression.

 

[psycho62]

Let me interrupt for one second and announce a new member of the household here in Missouri and a special thank you to Kelly @krazcool. My GK1 now has a companion the K1 .25.

 

[Bngen3]

Let me interrupt for one second and announce a new member of the household here in Missouri and a special thank you to Kelly @krazcool. My GK1 now has a companion the K1 .25. View attachment 409263

I have the same combo, both in .25 and also MO

 

[psycho62]

I have the same combo, both in .25 and also MO

Cool homie lol, that's awesome. My Gk1 is in .22 but I'm gonna pick up a .25 from Kelly eventually. I'm I'm Cape Girardeau. Nice to hear from ya

David

 

[psycho62]

I have the same combo, both in .25 and also MO

My K1 is .25 but I didn't want to wait and got the .22 GK1 because it was in stock

 

[steve-l]

Question:

So if you only fill to 250 BAR does this spring problem become nonexistent ?

My guess it would be less damaging, but spring stress is a combination of fill pressure AND power setting. I will make a test plate to accommodate a test probe in order to monitor that valve motion. It will answer many of these questions.

 

[Nomadic Pirate 66]

Let me interrupt for one second and announce a new member of the household here in Missouri and a special thank you to Kelly @krazcool. My GK1 now has a companion the K1 .25. View attachment 409263

I believe that is where I'll end up to eventually

 

[Nomadic Pirate 66]

My guess it would be less damaging, but spring stress is a combination of fill pressure AND power setting. I will make a test plate to accommodate a test probe in order to monitor that valve motion. It will answer many of these questions.

Ok so, if I set the pistol in the 50 FPE range and fill primarely to 250 BAR what is the chance of damaging the spring ?

Thanks in advance

 

[weevil]

What are the dimensions of the spring?

 

[sb327]

12.5 coils
1.2” length relaxed
.275” od
.039” wire diameter

Dave