AT44 QE Long .25 'tuning' advice needed

[toine]

I got my replacement QE Long from HatsanUSA a couple weeks back. Last weekend, I took it out for some testing over at Trenier Outdoors, seeing as Jeff had a shiny new compressor he needed to break in, plus I had lent him my SCBA tank while I was out of town.

Right out of the box, I was getting 16-18 shots on a 3000psi fill at or around 880fps before drop-off. 2 1/2 turns to 'de-tune' and I managed to get 23 shots within 3% ES from a 3000psi - 2050psi fill.

My question is simple. Is there anything else non-invasive I can/should do to the rifle? I'd love to be able to get another 7 good shots out of it, as that would give me 3 full mags per fill, however I do not know how feasible that is with just power adjustments and pressure adjustments alone.

[rsterne]

I have the same gun.... By plugging the bottom 3 holes in the valve, and increasing the preload slightly, I got 27 shots within 4% ES at 876 fps average from 195 bar down to 130 bar.... With 5 holes plugged, and the top hole drilled out to 0.180", I got 27 shots at 889 fps, or I could increase the preload one more turn and get 23 shots at 911 fps average within 4% ES from 200 bar down to 140 bar.... I did other more difficult mods after that and achieved more power, but at reduced shot count....

Bob

[Adamah]

rsterne, in your opinion is your valve mod pretty much the standard starting point for anyone with an AT44? I've got the same gun and my 18 shot string over my chronograph today looked like this: SD 5.9, AVE 875.2, ES 19.4. Thats with 25.39 Gr. JSB's on a 190 bar fill.