Its all in the velocity screw.
I am now having greater accuracy results with the MDR and CPHP 14.3.
Its long to explain but start by setting the hammer throw all the way back.
Set the preload all the way in and the velocity screw all the way out.
This has the gun at max power. Now you want to bring the velocity down
for your CPHP to around the mid 800 range, this seems to be where you
get the best accuracy for this pellet.
What I did at this point was turn the velocity all the way in and started backing
it out at 1/2 turn at a time and shoot one shot at 2500 psi fill. I keep filling it, backing it out
and shooting untill I got into the zone I wanted, Low to Mid 800's.
Now I have to make the adjustment to the preload so I am not wasting air and keeping accurate.
Start turning the preload back out .5 turn at a time from fully in and shoot a 10shot string starting at 2500Psi.
You will find you are dumping alot of air and the velocity spread is not bad but drops the psi fast in 10 shots.
You will dump about 200 psi Out of the MDR the fist 5 shots. The next 5 will drop you about 300 psi in the MDR.
I kept adjusting the preload out until I got to 1.5 out and the velocity screw was still set at 2.5 out.
That gave me good power, accuracy and not much wast of air. I only had 1 flier in a 20 shot string.
I posted this in the Marauder Owners forum and then copy past it here below.
Thanks so much again for your info.
Armed with your settings, I went out and gave it another go with the CPHP 14.3.
Drastic improvement. My best accuracy, but not best power curve.
I only got about 10 shots between the 845 to 850 range.
The next 5 shots were between 839 and 827.
The last 5 shots were between 823 and 818.
This was all done with the following settings.
Throw -max 100% back.
Preload - back out 1.5 turns from being fully turned in.
Velocity -2.5 out from fully closed.
The velocity screw was the secret.
At 20 yards, I shot a dime size group or smaller with one flier
I started at 2500 psi
2. 848.5 flier=1.5 low and about same to the right
5. error 2400psi end
10. 844.8 2300 psi end
15. 826.5 2100 Psi end
20. 813.5 2050 PSI at end.
Now please note that this is probably not the best it will get.
I ran out of light before completing adjustments and testing.
I should get this to where I have a much longer shot string
and closer FPS spread in that string.