Tuning Regulator Settings

[Freddy J]

When reading about tuning and setting the second Regulator, some gun have a third, I have to set my regulator to 156 Bar to reach 880 to 900 FPS while shooting 25.3 Grain pellets. Many videos show setting the second or third reg, to only 90 Barr to reach that same velocity using a 700mm barrel. Why is there such a wide range of settings to achieve the same results?

 

[Murfdurf82]

When reading about tuning and setting the second Regulator, some gun have a third, I have to set my regulator to 156 Bar to reach 880 to 900 FPS while shooting 25.3 Grain pellets. Many videos show setting the second or third reg, to only 90 Barr to reach that same velocity using a 700mm barrel. Why is there such a wide range of settings to achieve the same results?

Yes this is confusing, it would be interesting to know the science behind it. Or someone with a basic breakdown to pass a long.

 

[Madhatter]

Longer barrel more efficient. Think of a dragster. It will go a lot faster in a 1/4 mile than a 1/8 mile. Look at the difference in power say a.44 mag in a pistol compared to the power in a lever action rifle.

 

[Cantona256]

Yeah so with air rifles longer barrels means more speed.


“

Compressed air​

Now let’s talk about airguns. Precharged pneumatics (PCP) store compressed air until a valve releases some or all of it. Once the air pushes on the pellet it accelerates it down the barrel until the pellet exits the muzzle. Very much like black powder, the longer the barrel the higher the velocity for a given pellet in a given gun. The valve closes sooner or later and acts like the Fs in black powder. The faster it closes the sooner the pressure behind the pellet drops off, lowering, but not eliminating, the push on the pellet.

Think of an automobile you are trying to push. At first it moves very slowly, but the longer you push the faster it moves until it moves so fast that you can’t push it anymore. Compressed air works in a very similar way.

So, six guys push a car and it starts moving much sooner. Higher air pressure starts a pellet moving sooner — to a limit.”

https://www.pyramydair.com/blog/2022/06/how-barrel-length-affects-airgun-performance/

 

[Solo1]

Something i picked up on in matts vid of the drs tactical. He stated with the fx valve if you run higher reg pressure you essentially get a shorter valve opening as the higher pressure helps to close the valve sooner than lower pressure. This does not necessarily apply to all valves and i think why some guys automatically want to go to 150 bar when setting up

 

[TN_Yankee]

I had read somewhere years ago, the theoretically longest barrel you could have before friction & decreasing pressure take over to lower your speed, was somewhere in the 40-48 inch range. I'm sure there are all kinds of qualifications to that statement, but that's just what I keep in the back of my mind.

 

[MacGyver]

Valve volume, lift and dwell all have an impact on the amount of pressure you need inside the valve to determine a specific velocity/power level. It's kinda like comparing 1/2", 1" and 3" hoses all with different size nozzles on the end and the same water pressure. They will all spray different distances.