It's probably the ammo you were using. You set-up looks pretty good. I would try out the .3 and .4 weights. You should get better results from those weights.
As for the FPS, I'm not too sure about that. I would think a .25 would get to the target very quick if it could hit it. Have you checked airseal or actually chronoed it at 550 FPS? I would put my finger over the barrel and fire to see if there is a leak (make sure there's no ammo in the rifle).
As for the FPS, I'm not too sure about that. I would think a .25 would get to the target very quick if it could hit it. Have you checked airseal or actually chronoed it at 550 FPS? I would put my finger over the barrel and fire to see if there is a leak (make sure there's no ammo in the rifle).