Hi, i just went through the process of installing power plenum on my .25 FX Impact MKII and through the process of my first tune. Below os the picture of my final Chronograph. I keep getting these random 884 fps at times. Trying to tune for 895FPS with the 24 gr JSB Kings. I don't know if these drops of fps are normal to these guns or if there is something wrong with it. Any help will be greatly appreciated since i can not take it to a dealer in my country.