I use an FWB 300 (spring gun) for offhand practice. Been shooting it frequently for quite a while. I use a high-quality, match-grade pellet. I've fired 20,000 of them, different lots. Last night I ran out of one lot number and opened a new sleeve of the same brand, different lot. Immediately, the point of impact changed more than two MOA down and almost two MOA to the left. Visual inspection of the pellet shows nothing strange. I suppose I can adjust the sight and forget about it but I wanted to bounce it off of some more experienced people. I actually thought I was feeling a strange recoil in this essentially recoiless gun! Tried a few again this morning and have ALMOST decided it was a psychological reaction to the shot dropping so far off the target but I'm really not sure. Any thoughts? Many thanks.