Need help with velocity adjustment on a WGP mini with a pump kit

[CGPro856]

I have a pre-2K WGP mini that I just put a slice pump kit on and I can’t get the velocity to settle down. It starts low and ramps up on every shot up to low to mid 300s like 240 on the first shot then 260 then 280 then 310 320 then 330 and it hangs at 330 until the CO2 runs out. I’ve tried several different hammer springs and a couple different valve springs and it still does the same thing. the starting point can be different but it always ramps up over 300. I would try HPA but the slice pump kit for the mini does not have a pin to open the valve on the HPA tank and I don’t have the parts to rig up a bottom line just yet.

any ideas?

[Trbo323]

Are you running a hpr? If so, regulator seat might be going out

If not, what happens if you pierce the co2 and then let it sit for a minute before shooting? If you are not running a hpr I have 2 suspensions

1) you are essentially submarine dooring the valve with a fresh 12g so the pressure is too high and closing the valve. This is why you are getting low velocity to start and as the 12g is getting used the pressure is going down which is resulting in higher velocity

2) the co2 simply needs a little time to expand into the front block which is why the latter shots are higher. More time

If 1 is true, the few waiting minutes won't change anything and you will still see low velocity at the beginning shots.

If 2 is true after waiting you'll see higher velocities for the first few shots

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[Trbo323]

Also next time, no need to ask the same question in two different places. We will see it

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[CGPro856]

No HPR. Co2 right into the front block. I’ll try the waiting thing and see what happens although I suspect number one since I did have to go load up more paintballs a few times after piercing the co2 so I think it did sit for a while. The velocity definitely goes up as the co2 cools.

is there a remedy for this?

[Trbo323]

Run a hpr or at least a HPA tank and get the output pressure down. Hpr would give you more adjustability

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[Trbo323]

https://palmerspursuit.com/products/pps-aluminum-round-asa-stainless-1-8-npt

If you want to install a hpr on it this is how most people do it. One of these screws into the front block where your air line goes in now, regulator into the adaptor then a few macro fittings and hose or steel braided if you would rather do that to connect the ASA to the regulator

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[autococker04]

If you have a spring kit try heavy valve spring and medium or heavy main spring. Cockers can run on unregulated co2, and a heavy valve spring should allow less variation into the amount of co2 that gets through the valve.

downside is the pump stroke won’t be as nice.

[CGPro856]

This is a mini with a slice pump kit. The ASA screws right onto the front of the body and basically straight into the valve. I’ve been using 12 g CO2’s in a quick changer. Could it have anything to do with that? Not enough space for the CO2 to expand before it gets into the valve?

[Trbo323]

This is a mini with a slice pump kit. The ASA screws right onto the front of the body and basically straight into the valve. I've been using 12 g CO2's in a quick changer. Could it have anything to do with that? Not enough space for the CO2 to expand before it gets into the valve?

Yeah I saw your photos, that front block is threaded for 1/8npt which is what that ASA adapter is. I doubt it's a space thing. Assuming you are plugging that bucket changer into the ASA the whole air line is expansion space. Also if that were true I would expect your velocity would remain more consistent but low or high not climbing

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[CGPro856]

The pump kit replaces that front block with a vertical ASA that attaches right onto the front of the body so I was not using any kind of an airline. I’m going to try a bottom line adapter with a bit of an airline and see if that makes any difference but I’m using Nelson Springs rather than the Old original Sheridan Springs so I don’t think I’m gonna get it to work well on 800 psi. I will start looking for a high pressure regulator to use.

[CGPro856]

So. Where I’m at in case anyone stumbles across this post in the future.

I was unable to find a stiff enough valve spring to make this thing run on unregulated co2. Apparently the original setup used very stiff springs but what I have are the ones that the Phantom’s use. With the extra stiff blue valve spring and the regular silver hammer spring and 400 psi into the valve through a HPR, I get a decent adjustment range from the IVG. I can adjust from 200-300fps. At 270 ish, I’m getting just over 20 shots from a 12 gram. Good enough for now.