..it's a silly name, but two shooters kind of named it: "giggle gun" (not a real manly-man name, is it?).
Reason being, on the first shot, one guy looks up and told me, "It's out of gas." Chronograph had the expected reading, and I guess he didn't notice the hole in the target...rifle is just quiet enough that the internal "snap" of the hammer hitting the valve is louder than the shot. Once I pointed out the hole in the target's black to him, and he shot a very good 25yard group, he started smiling...giggling even...the name stuck.
OK...we know the power mods. Deburr, polish, transfer port, bolt probe, delrin valve stem, valve spring/hammer spring fiddling. Did all that.
Then decided to make it my back yard gun. After some experiments with lighter spring tension, found consistency and accuracy weren't real good. Slow moving heavy weight hammer didn't seem to be "getting it" at speeds under 730fps.
Took out the hammer and lathed it. Ended up 1/3 lighter. IDea being that a quick "smack" to the valve might open and close it QUICKER than a heavy weight punch. This it seems to do. Vel. dropped a little bit, but not a serious amount (and not as much as wanted..wanted it down in the high 600's).
Kept lightening the spring..swapped for an even lighter weight spring...once it got down to 700fps (.177/ 7.6gr. pellets) it became amazingly quiet. Yeah, the muzzle "weight" has something to do with it, but the same "weight" was on it before the mods and it wasn't nearly as quiet. The number of good shots per fill increased drastically.

Don't think it's the path to max. vel. It does seem to be the path to good consistency/accuracy at low speeds with large cshot counts.