I am probably going to reduce the velocity/power of my two .25s, a P35 and an Avenger. The P35 started out shooting the FTTs it likes at about 850 and it was accurate and I was getting about 70 shots per fill. But the regulator was reacting to the fact that the hammer spring was not set high enough to empty the chamber by reducing the first shot velocity a little. So I turned the hammer spring up until the velocity stopped increasing and then fine tuned that a little for smaller groups. Most recently I took the barrel off and cleaned up the barrel port, polished the barrel, and polished the crown. I gained 20 fps, there was an obstruction in the barrel port, but now accuracy seems worse. 895 fps may be too fast for FTTs. Shot count is also lower. So I may turn the regulator down and shoot for 850 fps again. That is only about 30 fpe but that should kill squirrels just fine.
My Avenger shoots FX 25.4s at about 930 fps. Close range accuracy is good but the one time I shot it at longer range it was not good at all, Again, I'm think lower velocity may help. On the Avenger, that is much easier to do than the P35, Reg is about 2100, I just need to degass and set it to about 1900, P35 has no gauge for the regulated chamber and access to the regulator is inside the air tube. So some disassembly is necessary. Fortunately I like the tinkering. Squirrel season is over a week from tomorrow. Then it will be time for retuning.