Today the load was shot through the clock.
At 39 yard, the speeds read:
1952 fps
1946
1952
1950 fps average
At 97 yard the speeds read:
1787 fps
1773
1773
1778 fps average
Taking these value to a ballistic program resulted in the following table.
In the mail yesterday came a couple of stainless vent liner from Busta. This morning one of these with a 0.028" flash hole was installed into the breech plug of the Mountaineer. Twenty three shots were taken this morning. Returning home the rifle was cleaned, and the flash hole of the stainless vent was measured at 0.029".
Hopefully tomorrow will find the rifle out shooting some more. The flash hole will be monitored. This load of 125g BH with this bullet may allow accurate shooting to 300 yard. It seems the speed of the bullet at 300 yard is far enough a way from the speed of sound to escape issues at the sound barrier.