Air Arms power curve

[stuartyboy]

Thought I would put a few pellets through my S410 to see what the power curve was like and I was surprised at the results.

I thought the higher the pressure the rifle was filled to, the higher the velocity. As you can see, that wasn't the case. Anyway, thought I would write down my results in case anyone finds it useful.

Filling the tank to maximum pressure of 200 bar, the first ten shots where as follows:

200 bar

Average of 539 fps. 10.2 ft ib

Next ten shots

Average of 543. 10.4 ft ib

Then average of ten shots as follows

545 10.5

546 10.5

549 10.6

Manometer on air rifle saying approximately 160 bar now

550 10.7

553 10.8

Manometer saying 150 bar

555 10.9

555 10.9

555 10.9

556 10.9

554 10.8

551 10.7

Manometer saying 120 bar

546 10.5

540 10.3

Manometer saying 100 bar

533 10.0

520 9.5

Manometer saying 75 bar

500 8.8

Pellets were Air Arms .22 Field. 180 pellets fired and the average of each 10 shots given.

For this rifle I would now be looking at filling to just over 150 bar for a good 40 or so shots.

There was very little variation between the individual 10 shot groups

[old'un]

18 minutes ago, stuartyboy said:

Thought I would put a few pellets through my S410 to see what the power curve was like and I was surprised at the results.

I thought the higher the pressure the rifle was filled to, the higher the velocity. As you can see, that wasn't the case. Anyway, thought I would write down my results in case anyone finds it useful.

Filling the tank to maximum pressure of 200 bar, the first ten shots where as follows:

200 bar

Average of 539 fps. 10.2 ft ib

Next ten shots

Average of 543. 10.4 ft ib

Then average of ten shots as follows

545 10.5

546 10.5

549 10.6

Manometer on air rifle saying approximately 160 bar now

550 10.7

553 10.8

Manometer saying 150 bar

555 10.9

555 10.9

555 10.9

556 10.9

554 10.8

551 10.7

Manometer saying 120 bar

546 10.5

540 10.3

Manometer saying 100 bar

533 10.0

520 9.5

Manometer saying 75 bar

500 8.8

Pellets were Air Arms .22 Field. 180 pellets fired and the average of each 10 shots given.

For this rifle I would now be looking at filling to just over 150 bar for a good 40 or so shots.

There was very little variation between the individual 10 shot groups

Ant no expert on this type of thing, but is it not the volume of air released when the trigger is pulled that increases the FPS?

[oldypigeonpopper]

hello, am no expert either but having owned and used many PCPs including a 410 never worried on power curve or any other technical thing, all my rifle were below 12 ft llb. i always filled 5 bar below the recommended and shot till it went to 5 bar before empty,  410 was 185 bar,  have 2 FX now and both filled to 10 bar below just to hold the internal seals and that is how it will be till after lockdown

[stuartyboy]

17 minutes ago, old'un said:

Ant no expert on this type of thing, but is it not the volume of air released when the trigger is pulled that increases the FPS?

Yes, spot on. Not being that knowledgeable about airguns, I presumed that any power curve that exists would be caused by high pressure in the air cylinder causing higher FPS then as the pressure drops, so would the FPS. But my unscientific experiment has shown the power has a curve like a rainbow as opposed to starting high then dropping off regularly. Possibly due to the higher cylinder pressure holding back the hammer somewhat. But then again I could be talking rubbish

[oldypigeonpopper]

10 minutes ago, oldypigeonpopper said:

hello, am no expert either but having owned and used many PCPs including a 410 never worried on power curve or any other technical thing, all my rifle were below 12 ft llb. i always filled 5 bar below the recommended and shot till it went to 5 bar before empty,  410 was 185 bar,  have 2 FX now and both filled to 10 bar below just to hold the internal seals and that is how it will be till after lockdown

hello, your 410 is 190 max so nothing to stop you filling to 185, these rifles are tested with far more pressure

[sportsbob]

1 minute ago, stuartyboy said:

Yes, spot on. Not being that knowledgeable about airguns, I presumed that any power curve that exists would be caused by high pressure in the air cylinder causing higher FPS then as the pressure drops, so would the FPS. But my unscientific experiment has shown the power has a curve like a rainbow as opposed to starting high then dropping off regularly. Possibly due to the higher cylinder pressure holding back the hammer somewhat. But then again I could be talking rubbish

The reason for that is when the hammer hits the valve for it to open it has to push against the weight (pressure ) of the air in the cylinder  which is forcing it closed. As the pressure drops the valve can open a little more or for a little longer which allows a little more air into the barrel. A great deal of design goes into the valve design to help it "regulate" the air flow,  this is why a regulator improves things because the pressure on the valve is a constant.

[bruno22rf]

Shot the S410 for many years - always filled to 170 bar then carried a pot of 50 pellets - the gun will put these within 10 fps of each other and no hunting trip is likely to need more than 50 shots.

[stuartyboy]

1 hour ago, sportsbob said:

The reason for that is when the hammer hits the valve for it to open it has to push against the weight (pressure ) of the air in the cylinder  which is forcing it closed. As the pressure drops the valve can open a little more or for a little longer which allows a little more air into the barrel. A great deal of design goes into the valve design to help it "regulate" the air flow,  this is why a regulator improves things because the pressure on the valve is a constant.

Thanks for that

[strimmer_13]

My falcon fills to 200 bar, but if you fill it to that the first 15-20shots are 10ftlb. At about the sweet spot of about 170bar it's 11.2 and regular for roughly 30 shots. So never bother to fill past 170. Think it's the same with most guns unless it's regulated. My fx is regd and I fill to max

[Mice!]

23 minutes ago, strimmer_13 said:

My falcon fills to 200 bar, but if you fill it to that the first 15-20shots are 10ftlb. At about the sweet spot of about 170bar it's 11.2 and regular for roughly 30 shots. So never bother to fill past 170. Think it's the same with most guns unless it's regulated. My fx is regd and I fill to max

I was told with my rapid years ago, no point filling to 200 as your wasting pellets and air. I just fill to 180 now.

[Ultrastu]

So a good guide with sub 12 airguns is to have your gun shoot in a pressure range that gives 0.75 of a foot pound  

So your max energy is 10.9 fpe . So you can shoot a pressure that gives you 0.75 fpe less than that or 10.15 fpe .at both ends of the fill so in your case 200 bar down to 110 bar .

With this 0.75 fpe variation you wont be able to see or even shoot the difference this makes at 45 yds .which is about max range for a sub 12 .22 gun . 

Obviously if you extend the shooting range up to say 60 yds you may see the difference (presuming both the gun and your talent /weather allows you to see the difference ) .

Personally id fill to 190 bar shoot to 110 and count how many pellets that gives you and count them out into a pot .and then forget about any power curve its not a factor to worry about inside 45 yds .

[washerboy]

Main reason I sold my mk1 S200

My first and last pcp

[oldypigeonpopper]

4 hours ago, Mice! said:

I was told with my rapid years ago, no point filling to 200 as your wasting pellets and air. I just fill to 180 now.

hello,  my FX has a bottle and tube and has a max bar fill of 220, you only waste air releasing pressure after filling, nothing wrong in filling a PCP 5 bar below max and shooting till there is about 10 bar providing the seals are in good order, leaving a PCP with to little air for any length of time you might find with a pump not easy to charge.