Chrono Results for FX Royale - Now what?

[jimreed1948]

FX Royale 500 .25 cal, 23.4 JSB pellets

I was able to spend some time yesterday with my chrono and rifle.  I shot 9 different strings, starting at the 210 bar and working down with the pressure.  Listed below are the results.  I filled the rifle to the 210 bar according to the gauge on the fill bottle.  After each string I looked at the gauge on the bottom of the rifle and used this as my mark.

To me it looks like the 6th String at the 150 Bar is the best with the following results;
Hi Vel:  913
Lo Vel:  904

Ext Spread: 9
    Std Dev: 2

So now what?  How does this work?  Should I only fill to around the 150 bar and shoot 10 rounds or so and refill to 150.  Is there a method to this madness that I'm not seeing or doing???

[Sfttailrdr46]

  Current wisdom is fill to slightly higher pressure than where the FPS peaks and shoot down from there. Just play with your start and finish pressures to develop the desired results

[PlanB]

Is your 500 regulated?
Pellets are 25.4?

[rsterne]

I would suggest starting at about 160 bar, and shooting about 28 shots, that works out to about a 4% ES total, from 880 fps to 915 and back down.... That is a good string for out to about 50 yards....

Bob

[jimreed1948]

Is your 500 regulated?
Pellets are 25.4?

Non regulated

[jimreed1948]

I would suggest starting at about 160 bar, and shooting about 28 shots, that works out to about a 4% ES total, from 880 fps to 915 and back down.... That is a good string for out to about 50 yards....

Bob

Thanks for the reply.  I'll give that a try.  I guess increase the pressure for longer distance?

[rsterne]

You misunderstand.... The ES (extreme spread) of about 4% at 50 yards or less will be basically unnoticeable.... Beyond that the velocity variation will start to show up as vertical dispersion at the target.... At 100 yards, you should strive for an ES of about 2%.... That would mean starting at about 153 bar and stopping after about 20 shots to keep the extreme spread within 2% instead of 4%....

Bob