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Slow fps Impact X 700mm .25
- Thread starter Avidrob
- Start date
One thing jumps out at me....hammer spring tension.
You're using slightly more tension for 25bar lower pressure. I have to wonder if you had sufficient tension for the higher pressure.
Your velocity loss going that far down in reg pressure isn't really that much.
You're using slightly more tension for 25bar lower pressure. I have to wonder if you had sufficient tension for the higher pressure.
Your velocity loss going that far down in reg pressure isn't really that much.
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HST at 140 was 18mm HST at 165 was 17.5 mm so the tension at 165 is higher.
My method to find hst is to wind it up tight with the power wheel set on max then turn the wheel down until shots just begin to slow. This might be #1 or #2. if it is #2, i will set the wheel to # 3 then then measure that distance and adjust screw on the wheel #max setting to that measurment. This way the hammer is just a tiny bit stonger than is needed for the reg pressure, so helps avoid low speed first shot if reg creeps.
Hope that makes sence
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My mistake, I had it backwards. But that is very close to being the same amount of tension.
If we look at your latest efforts in reverse, going from 140 to 165bar only got you an increase of 40fps.
0.5mm isn't much of an increase in hammer spring tension and 40fps is barely over half the gain of what I expected you to get given the significant pressure difference.
I still have to wonder if you're getting sufficient hammer strike for 155bar or higher setting.
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Totally agree with what you thinking, i think the same but my riffle disagrees, hence why im here for expert advice. Something is wrong somewhere. Even maxing out the HST sees no gain over what iv posted b4, these are the maximum velocities for any given reg pressure, and the hst has been reduced to the minimum before the velocity starts to drop.
So i played around again for fun just to see absolute max fps i can get.
I milled and installed a 5 gramm hammer weight, maxed out the HST to the point where it will only just cock, and set the reg at 165. With the VS wide open i I get 919fps with 34grs and 1040fps with the 25grs.
With the VS set properly this comes to 900 and 1010 respectivly.
Doubt it will be accurate at that but lets see tommorrow
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Keep i mind this has now had multiple mods, including Huma reg, 6mm valve seat, 5 gramm hammer weight, ported inlet and probe and delrin c3.
Other than a larger valve tube/plenumn this really seem like as far as i can go with it.
Other than a larger valve tube/plenumn this really seem like as far as i can go with it.
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There's the 75fps (80) I was expecting from 25bar of pressure (if I've been following along correctly).
Now I guess you can lower to 140 and check performance?
Now I guess you can lower to 140 and check performance?
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