Recently I discovered that I was only getting 20 useful shots from my CZ 200s. Target Specialists fixed the problem by shooting a long string of shots over a chronograph and adjusted the striker spring and chronographed every shot. Obviously a very time consuming exercise.
To cut a long story short, after optimising the rifle I am now getting 50 shots with the following details:
Average velocity 789 ft/s
Standard deviation: 6.87 ft/s
Coefficient of variation: 0.87%
Max filling pressure 190 bar
Min pressure to fall in above range 130 bar