Regulator pressure vs shot count
- Thread starter jwv162
- Start date
JWV162,
I will try to give you a solid answer, without miring this in math.
Assumption: We are talking about 1 airgun, which between pressure changes is not being modified for anything but hammer strike to idealize shooting at 1 velocity for the full range of test pressures.
The ideal regulator pressure will be along a bell curve. As regulator pressure is adjusted up, the valve must be open a shorter period of time, to keep the same velocity as a lower pressure setting. As the regulator pressure is adjusted down, the valve must remain open longer, to keep the same velocity as a higher pressure setting.
As your desired ideal feet per second (FPS), or Foot Pounds Energy (FPE), goes up, it normally requires a greater pressure to make it happen. You won't get 1000 FPS velocity of your pellet, with only 200 pounds of pressure being offered by your regulator. It will be hard to adjust down to 500 FPS velocity of your pellet, as pressure the regulator is set for climbs above 4000 PSI.
High energy shots require more air, than low energy shots. A well designed valve can accept a "range" of pressures and produce and produce a reasonable range of shot to shot variation (balanced valve). However, there will be "a pressure" which the regulator will achieve a specific pellet velocity, with the least wasted air and highest efficiency.
On a well ported and polished air rifle, which has optimized airflow inside it, it will require less pressure to achieve the same velocity as another rifle which is less well ported and polished. Most really good .25 caliber air rifles will achieve 40 FPE with 25.39 grain pellets at only about 1800 PSI of regulated pressure... and with good efficiency.
For a given air rifle, there will be an ideal pressure to hit a specific velocity with good efficiency. You will need to spend some time reading what others have achieved within the forum, or burn a few hundred pellets over a chrony to figure out where your sweet spot is. Or, you can send it to a tuner, who through the experienced use of a Chrony, can tune your air rifle to obtain any reasonable goal you set (power or shot count being goals many people are trying to achieve).
Generally, you want your pressure lower for a maximum length shooting string, and a higher pressure for a harder strike with more FPS.
I will try to give you a solid answer, without miring this in math.
Assumption: We are talking about 1 airgun, which between pressure changes is not being modified for anything but hammer strike to idealize shooting at 1 velocity for the full range of test pressures.
The ideal regulator pressure will be along a bell curve. As regulator pressure is adjusted up, the valve must be open a shorter period of time, to keep the same velocity as a lower pressure setting. As the regulator pressure is adjusted down, the valve must remain open longer, to keep the same velocity as a higher pressure setting.
As your desired ideal feet per second (FPS), or Foot Pounds Energy (FPE), goes up, it normally requires a greater pressure to make it happen. You won't get 1000 FPS velocity of your pellet, with only 200 pounds of pressure being offered by your regulator. It will be hard to adjust down to 500 FPS velocity of your pellet, as pressure the regulator is set for climbs above 4000 PSI.
High energy shots require more air, than low energy shots. A well designed valve can accept a "range" of pressures and produce and produce a reasonable range of shot to shot variation (balanced valve). However, there will be "a pressure" which the regulator will achieve a specific pellet velocity, with the least wasted air and highest efficiency.
On a well ported and polished air rifle, which has optimized airflow inside it, it will require less pressure to achieve the same velocity as another rifle which is less well ported and polished. Most really good .25 caliber air rifles will achieve 40 FPE with 25.39 grain pellets at only about 1800 PSI of regulated pressure... and with good efficiency.
For a given air rifle, there will be an ideal pressure to hit a specific velocity with good efficiency. You will need to spend some time reading what others have achieved within the forum, or burn a few hundred pellets over a chrony to figure out where your sweet spot is. Or, you can send it to a tuner, who through the experienced use of a Chrony, can tune your air rifle to obtain any reasonable goal you set (power or shot count being goals many people are trying to achieve).
Generally, you want your pressure lower for a maximum length shooting string, and a higher pressure for a harder strike with more FPS.
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The lowest set point that allows you to hit roughly 5% or so above your intended max FPS will provide the best shot count per your regulated application would be the best short answer IMO.
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The answer is yes, BUT other changes you make (or don't make) to the working parts of the gun will depend on what affect it has (ie up or down).
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So then do u (in general) while achieving your desired fps, is it better to have the lowest reg pressure and more hammerspring tension? Or spring backed out for the highest shot count?
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You want the lowest reg pressure that allows you to hit 5% above intended FPS. From there you want to fine tune hammer weight and spring rating to minimize or eliminate hammer bounce. Changing port size will change what FPS you get at specific pressure. There is no single condition set that meets the criteria of all air guns.
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