Air Arms S400 Chrono
Put my AA over the Chrono today . Was somewhat shocked to see I am only getting 10.5 Ft/Lb .Avion tells me this is what the British guns are being set to , to prevent over power weapons with heavy pellets . Anybody found the same problem ? Maybee I just dont know how to use my chrono properly ! B)
Albereth , just going on the spec from the lid of the pellet.Think I will try that as well .Got a scale for reloading building up a layer of dust.
I recently done a test over 180 shots and found the following:
Rifle - S400 Classic
Pellets - JSB Exact @ 8,4g
Altitude - Sea level
Chrony - Beta Master
Initial fill pressure - 190 Bar (from gauge on rifle)
@ 190 Bar - 740 fps = 10.28 ftlb
From 150 to 100 Bar - 781 to 795 fps = 11.45 to 11.86 ftlb
Below 100 Bar - 760 fps = 10.8 ftlb
I stopped at 50 Bar - 645 fps = 7.81 ftlb
According to me you most consisitend power level would thus fall between 150 to 100 Bar. You will get 80 full power shots between these pressures.
If you like, drop me a mail and I will forward you the test results. Please note that these are test I have done for my personal intrest, please regard it as such.
Thaks MCj.Feel a bit better after seeing your spreadsheet. I see I will have to sit at the range and do the same .Spot checking does not seem to be fruitful.How long did it take you to do that test ?180 shots should sound like work but rather sounds like fun I'll just tell myself that while I am busy doing the test.
First, I found myself a nice spot on a farm between the vineyards as I too though it is going to take me quite a while. Setup my table, bench rest and chrony.
Once that is done, you don't have to make sure that you not going to shoot your chrony into kingdom come..... it actually goes relatively quick, it took me about 2 hours.
I took the rifle pressure reading everytime the 10 fps difference.
Hope this helps. It is actually not that bad because it was very interesting for me to see how the speed rise and com down again. For you it might be interresting to see how your speed compares to mine.
I am very interested to see how it will compare because I have doen the testing at sea level and you will be doing it at altitude.
According to my info Johannesburg is roughly 1690 meters above sea level with air dencity of 0.989 kg/cub m and barometric pressure of 85.586 kilopascal
Sea level has air dencity of 1.2 kg/cub m and barometric pressure of 101.325 kilopascal
All the above means that the speed of the same type of pellet used, should be faster, but it would be interesting to see by how much?
Please let me know!
Hello Guys ,
My AA S 400 was similar , at full charge with AA field pellets I was chronoing abput 690 to 710 . Once the air dropped down to 155 bar , the speed went up to 795 - 815 . All the way through to 100 bar . I did'nt go lower . Accuracy is perfect between 155 & 125 , maybe 60 to 80 really good shots .
Shot at + / - 650 m above sea level .
Gun has now shot well over 3000 pellets .
MCJ , I will get back to you as soon as I have done my test.Thanks so far.