Greetings everyone. Newbie question. I have a qb78. Can I fill it with hpa instead of co2 if I keep the pressure BELOW 800 psi or will it explode? It has a female fitting on the front for bulk fill co2. Thanks for all the replies. ..Andy
can I fill a qb78 with hpa?
- Thread starter puertorico
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I'm gonna say "NO," if only because high pressure air and any kind of non silicone oil (which the inside of your gun is likely slathered with) makes for an explosive combination. If you research it, there are plenty of guys running HPA in their QBs. Some swear they make excellent PCPs. I don't know the details, but there is a lot more work involved in converting your QB to safely use HPA than just filling it carefully. Look on "Air Gun Home" site, specifically posts by rsterne, he is a genius with the QB. Unless I'm mistaken, he may be posting on this site too.
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You need a dedicated PCP conversion to run compressed air in a QB. First off, you won't get any shots on 800psi of air. Second, the chances of overcharging are high and that could result in a catastrophic incident.
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There are several ways to do so , safely, and likely other very unsafe ways so DO be carefull!
As you have the bulk fill on the front already, if you can live with a coil line attached that would be the easy way out, hook a ( correctly rated for the MAX psi you could see-likely 1,800psi before the safety/burst disc blows) a ninja 850psi regulated bottle to the line,hook line to rifle and fire away.
The other way would require machining, by way of adding a QB79 drop down tank adaptor. These do not ( to me) seem so safe when used as supplied, the attachment screws are to close to the tube end, but, a good machinest would have no problem redrilling so they are further back - this will leave only 1 o-ring to seal-.
Just filling your tube ( id NO flammable lubes inside) will give one good shot, maybe 11fpe?
QB78 with 79 adaptor and valve anchors screws.
John
As you have the bulk fill on the front already, if you can live with a coil line attached that would be the easy way out, hook a ( correctly rated for the MAX psi you could see-likely 1,800psi before the safety/burst disc blows) a ninja 850psi regulated bottle to the line,hook line to rifle and fire away.
The other way would require machining, by way of adding a QB79 drop down tank adaptor. These do not ( to me) seem so safe when used as supplied, the attachment screws are to close to the tube end, but, a good machinest would have no problem redrilling so they are further back - this will leave only 1 o-ring to seal-.
Just filling your tube ( id NO flammable lubes inside) will give one good shot, maybe 11fpe?
QB78 with 79 adaptor and valve anchors screws.
John
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