Best Velocity LG300?

[Albert T]

The air regulator of my Walther LG300 Mk.1 was damaged, so I had it replaced by a Mk.2 regulator. When testing the velocity, it shot the pellets at 387m/s (614 ft.second). The groups were huge. Using the screw behind the hammer block I reduced the speed to an average of 178m/s (583 ft/second, using RWS Meisterkugeln). This reduced the groups to an acceptable size.
What is the recommended speed for these rifles/pellets? (In matches I use the RWS R10, 4.49mm).

Albert T
(The Netherlands)

[TenMetrePeter]

The German F mark is for max 5.53 ft lbs energy approx (7.5 joules) and for 8.2 grain R10 rifle pellet that's a max of about 550 ft per second. (168 m/s)

I would suggest keeping just below this.