I was curious on what makes a big bore valve dump I got a .457 I've power tuned I took out the valve retainer and return spring got way more power but I was thinking about dumping all the air In one shot it has pretty small air tube only 150cc and 3000psi max fill how do you get it to valve dump??
Other Big bore airgun valve dump???
- Thread starter anonymous_.457
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When the pressure in the tank drops to a certain level, the valve remains open due to insufficient pressure to close it, resulting in a dump. The specific pressure at which this occurs may vary, and consulting someone with the same PCP model could provide clarity. However, it's important to note that valve dumping can strain the components, so caution is advised. Opting for a weaker spring could offer a balance, but seeking advice from a more experienced individual is wise. Safety should always be the priority.!
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When the pressure in your .45 caliber reaches a certain low point, which I'm not certain of, each subsequent shot reduces the pressure further. If you continue shooting, eventually the pressure will drop to a level where it can no longer keep the valve closed, resulting in a dump.
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Yeah my .457 pbba is a 3000psi fill I thought that's how most dump guns work fill it to the max pressure and it dumps all 3000psi in one shot
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I think your best bet is to wait for someone who has the same 45 cal, sorry I couldn't help you.
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Yeah but what's weird it doesn't use a return spring and I can shoot it down all the way to 0psi and it never valve dumps
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Hi.
When you fire your airgun, valve stem is expose to airtube presure. So, that presure will force to close the valve. It doesnt need a spring for that. Spring is needed to keep valve close when you need to fill airtube from zero with a pump.
Force that act against valve stem is stem area multiplied by airtube presure.
For 4mm stem and 100bar closing force is 12,56kg/cm2.
When you fire your airgun, valve stem is expose to airtube presure. So, that presure will force to close the valve. It doesnt need a spring for that. Spring is needed to keep valve close when you need to fill airtube from zero with a pump.
Force that act against valve stem is stem area multiplied by airtube presure.
For 4mm stem and 100bar closing force is 12,56kg/cm2.
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Yeah I understand that but I'm trying to figure to get it to dump all the air for more power
That sounds really undesirable. If you want more power the answer is usually more pressure and more hammer spring.
In any case I'll bet there's no easy way to make it dump a full tank unless it was designed to do so.
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I also don't understand why you would want to put that much stress on your rifle. Imo it sounds like a horrible and dangerous idea.
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Dumping all the air will not increase power any more than holding the valve open until projectile reaches the end of the barrel. The gun will get louder and recoil harder (due to muzzle blast) but the projectile will not go any faster.
Are you currently using a chronograph?
Dave
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