Out of the box, averaged 563fps with 14.3gr. and a 10fps variation. Not bad, about average.
(1) Tuned the trigger...like some have posted, the overtravel screw is backed out so far it's liable to fall out and the sear engagement is super deep.
(2) Removed the barrel to clean the rest of the shipping ear-wax out of it (with barrel off the gun, can blast it with carb-cleaner).
(3) Barrel holding screw was one-finger-tight as issued...and had that internal burr around the threaded hole that cuts the o-rings. Interresting, there was a burr right under the tapped hole for the set scew, which looked like they ran the tap in a tiny bit too far and it "dinged" the opposing side. Deburred and polished the inside of the reciever and bolt way, replaced o-rings.
(4) Bolt handle set scrrew was loose..bolt was loose...deepened the little detent in the bolt and tightened the screw on reassembly.
(5) Replaced the transfer seal with ice-maker line seal.
(6) Bolt probe passage measures right at 7/64ths....which is the drill size for a 6-32 tap, so it's a pretty common size.
(7) Drilled the bolt probe's transfer port to 7/64ths.
(

Cleaned the hammer and spring and re-lubed with a little silicon grease.
That's it...left the main tube alone, didn't touch the valve.
Averages 601fps/14.3gr with a variation of 4fps over 10shots.
When I ordered this, posted that I'd quit as soon as the chronograph winked out 600fps...which it did...so I'm leaving the internals alone.