Calculate Your FPS in Easy and Effective Way

[brihacharan]

After Tuning my rifle under guidance of MR Basu..These are the results[AVG velocity]
Pellets used Mastershot flat heads,
Note:-Muzzle velocity will be Higher that avg....
04/08/2013 1:14:00 PM , 1 , 745.74246
04/08/2013 1:14:14 PM , 2 , 744.85228
04/08/2013 1:14:33 PM , 3 , 739.33649
04/08/2013 1:14:48 PM , 4 , 741.97384
04/08/2013 1:15:02 PM , 5 , 738.24312
with proper tuning Indian air rifles can do much better
at least better that factory setting...

> Congrats Harsh! Well done.
> With an avg fps of 740+ you have achieved the optimum fps.
> Chances are with RWS / JB etc you may hit 750fps consistently
Briha

[pratik_mahale]

Congrats harshvardhan

Please share the tuning details which will be helpful for all the members

[harshvardhan]

Thanks Pratikji......
I will definitely share every thing in details..
but not getting time to compile everything....

[harshvardhan]

Molly Has shown its magic..
These are the result after applying thin coat of Molly

[pratik_mahale]

Good work Harsh
Is this reading with pellet seating because with pellet seating I get around 90-100 fps more velocity

[pratik_mahale]

My personal experience is original IHP spring is more powerful than any other Indian make spring & your reading also proving it

[brihacharan]

My personal experience is original IHP spring is more powerful than any other Indian make spring & your reading also proving it

> This is Good News
> Wonder if IHP has re-engineered the mfg process along the way
Briha

[harshvardhan]

Sorry pratikji,
I am using cherokke 27 spring.
IHP spring was able to deliver about 650 fps....
While using IHP spring pellet seater has given me advantage of 10-15 fps,
but now...it dramaticaly drops the fps by 10 to 15.....

cheroke 27 is powerful and nice fit in spring guide..only thing
i have done to reduce the twang and vibration is installing a tight fit piston shimming by coke bottle..
and bingo..though recoil is there but no twang....

[pratik_mahale]

I have used cheroke 27, TAS 27 & Target tune spring but all need more power for cocking plus more vibration compare to IHP Spring & less velocity

[harshvardhan]

oh........My IHP spring was old.....
cheroke worked for me...vibration is controlled by shimming inside piston.....

[Basu]

Dear Harsha,
Please put some screen shots to understand as to how the exact time should be captured of a sound sample in Audacity.

Basu

[sathya.sniper]

need some help over here!!!
There is a small doubts in using audacity. on behalf of a my frnd
When using audacity to find out the distance between the spikes.
The highest spike is the point to be recorded from. But there are spikes in upward direction and also in downward direction also... And in some cases the spike pointing downward is prior to the spike pointing upwards. so got confused from where to calculate.



the above case is my shot string i have selected the area of selection.
At the end i have selected the spike pointing upward and i get 0.026 sec, There is a spike downward before that if selection is upto that limit I get 0.025 sec and it gives me more fps than the previous result !!


but in the lower case the shot sting is from frnd..... there is a spike pointing downward before the spike pointing upward. Which one is to be considered.


Experts in audio field please help me and guide me through.

Regards.

[Basu]

Dear sathya,
Ref pic. no 1
The firing sound is the first tallest spike to be captured since the sound of air blast become loudest the moment pellet leaves muzzle.Therefore you captured it perfectly to begin with.I understand that this is the sound sample of IHP National 35.
To give a little more clarity , refer to 2nd pic.
I understand that this is the sound sample of SDB45 ,which is a very quiet gun.Here one need begin capturing form 2nd talest spike only for the same reason as said earlier.
When pellet hits the tgt ,any 1st spike ,upward or downward does nt matter ,needed to be captured upto so as to get real time.
This is purely my view .Expect other to give views as well.

Basu

[bennedose]

Sathya the time difference between up spike and down spike is so small that your muzzle velocity difference will also be very small. When it comes to very small differences like this your accuracy can be affected by things like whether the muzzle was 10.02 meters away or whether it was 9.98 meters away. Also the up-down values can vary from shot to shot. Another problem is echo - if there is a wall a few cm away the spike will be affected by the echo. The ideal recording would be in a soundproofed anechoic chamber.

I believe that the best thing to do is to take at least ten readings. See if all those readings give you the exact same down spike first. if they don't then just take the reading from the tallest spike up or down and average out ten readings. I usually take the average of 3 to 4 readings.

[Basu]

Dear benne.
Did you mean the down spike is to be captured only but not the tallest spike ?? Then why ??

Basu