Marvin,
Not sure what you are looking for in a .25 but with just a heavier hammer you can easily get 80fpe and a little more with the newer AF high-flow valve. To get 90fpe out of it (w/42gr pellets) you might need a little valve work (like polish, etc.). My .25 has the valve worked with a custom tophat and valve stem. You can actually get 90+fpe with heavier pellets than the usual 42gr EunJin/SamYang without too much modding. There are 50-60gr .25 pellets out there that will give you lots of Kinetic Energy.
I have tried 2200psi (not 2K) on the .22 and it shoots very nice and mouse-fart quiet with lots of "lower velocity" shots. I like the 2500psi fill because I get 25 shots in the 900's (w/Kodiaks) and about another 25 in the 800's. I do some night hunting for possom and racoon and like to be in the 40-50fpe range when hunting for these large critters, although I know I don't need it. It's a psychological thing.. but they are tough critters and I like to bring them down with 1 shot so the extra power does not hurt. There 's also fox and coyote around here so you never know what's going to show up at the bait 17yds behind my house. Yesterday it was a "warmer" day so I climbed up and repositioned my outdoor lights in the back so now the light reaches farther out (25-30yds) from the house. I have since moved the bait out to 23yds where the woods/tree-line starts where the nacternal critters might feel more comfortable. I then shot at paper on a 2x4" that I positioned next to the bait and the 32gr Eley slugs (look just like .22 bullets) @900fps (57fpe) with a fresh 2500psi fill and at the lowest PW setting were sticking out of the back of the 2x4" so I think I 'm all set for some night action, hopefully soon :-) It's been 3 weeks since I got a possom and 1.5wks since a large ~25lb racoon came to feast on the hot dog I had cut up in pieces, but he heard me putting the window up and took flight since he had eaten almost everything by the time I woke up (alarm went off at 4:30am!), got the gun, loaded it, and tried to get into position. So you see why I don't normally fill to 2000psi or less.. ;)
