GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Big Bore AirGun Gate => Topic started by: Fullblown on October 03, 2019, 09:49:48 PM
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Is helium safe to use in the DAQ rifles? Does anyone know of an instance where helium has been used in those rifles? If so, is there any numbers out there.
Does anyone have the numbers for a DAQ .58 short rifle?
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I think if you abide by the pressure limits you can put any gas (or liquid). HOWEVER!!! Please DONT use pure Oxygen or any flamable gas or liquid!!!
Dennis tests with hydraulic fluid which is very heavy, helium is very light which is how the pressure imparts more speed on the projectile and less pressure is needed to move the lighter gas.
I tested my .58 short rifle starting at about 3000psi with air and a 437 grain short minnie bullet at about 90 degrees Fahrenheit, 26 feet above sea level (on a Saturday in September 2019).
671 fps = 437 fpe 3000psi
665 fps = 429 fpe maybe 2200psi?
There is probably a calculation to get FPE with helium using the weight of air to helium. Maybe Bob will chime in.
If you test with helium, please post your results.
Try
https://www.gatewaytoairguns.org/GTA/index.php?topic=70856.msg932123#msg932123 (https://www.gatewaytoairguns.org/GTA/index.php?topic=70856.msg932123#msg932123)
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FPE is just bullet mass times velo...doesn't matter what medium is used to attain the velo....several good free online calculators...and pressure is pressure no matter how or what produced produces it. It's the mechanical aspects that dictates what happens with what medium.
YEAH DON'T MIX FLAMMABLE ITEMS WITH O2.
Good Hunting
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Helium is 1/7th the density of air.... A high powered rifle like a DAQ will discharge roughly the same mass of air from the muzzle as the bullet, so in other words a large amount of the available the energy is being used to accelerate the air instead of the bullet.... Roughly speaking most Big Bore rifles on Helium get about 50% higher FPE than on air at the same pressure.... The exact gains depend a lot on bullet weight, and how the gun is tuned.... Lighter bullets (which suffer more FPE loss to the air mass) can gain more by of that loss back when using Helium than heavy bullets....
Bob
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Same bullet with air goes about 320m/s if I remember correctly. Very cold weather on sunday, around 5deg C.
(https://img.aijaa.com/m/00516/14752886.jpg) (https://aijaa.com/7b1GoT)
Not a DAQ, but just to give the idea.
Marko
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Very cold weather on sunday, around 5deg C.
Another month and that will seem like a pretty warm day lol.
Al
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You have an excellent point Al!