Episode 2 of the Daystate Huntsman Revere 

I've got the same rifle in the walnut stocked version. My reg is set at 155 bar and with the JSB 18.13s it consistently shoots at 850 FPS + or - a couple until it drops off the reg at 44 shots.

That guns so new, could be regulator not fully broken in/ seated yet. Could need hammer spring adjusted. But...in other video, you had a random 800fps read on your chrony, and no change in POI, so my money is on your chrono being off. Which is what you also thought then. My current fav chrony, and I've got 3, is a chinese one off Amazon for $30. It isn't light dependent, hardly ever errors, and fits in range bag.

Good review. Looking for the third review. Is it out yet?

That's a huge dropping in fps for a regulated gun