Ok, so I tuned my Maverick, Black Betty, for 880FPS on pw7 shooting JSB 44.75 pellets. Gun was zeroed at 30 yds shooting through the same hole. So good to go, right? Well, went out to go groundhoggin today, started off shooting at some starlings at 50 yards-missed. Grackle at 50-missed-What! Threw up some targets at 60, 70, 80, 90, and a 100 yds. Shot at the target with the settings from the previous shooting at that distance last week and completely missed the target. The gun felt like the power had dropped way off. Threw up a 30 yard and I was 3 moa low! This was supposed to be my zero. Maybe the scope shifted somehow and I have a 3moa offset right? Wrong! Threw up a 40 yard target and I was 5moa off and that definitely told me that my power was way off. No way to check my power in the field, which might be a good argument for a pocket chrony. So I had to head back home to see what was going on. Put Black Betty on the chrony on pw7 and she only showed me 673fps! What the heck, expeicially since I had her set to 880 earlier. Dropped her chassis and the powerwheel to reveal the problem. The adjuster screw on the hammer spring adjuster was all the way clockwise! See photos. This screw is very easy to turn and I surmise that this screw will turn on its own or when you turn the power wheel since the head of this screw is seated against the back of the power wheel. So I took couple of measurements with the screw all the way in at 673fps pw7 to 880 fps pw7. So at 673fps the measurement of the adjuster is 15.8mm plus 1.8mm for the head of the screw for a total of 17.6mm. For 880fps at pw 7 a measurment of about 19.1mm. I adjusted to that and put locktight on it and let that setup So this is the second time I had a loose screw on this adjuster. The first time was the side screw that came out all together jamming the cocking. I'll try groundhoggin again tomorrow morning. 
