Sighting issue.

Hi all

I'm having some issue sighting in my .25 marauder. So when I first got it I sighted it in with no problems. Then one day I had a problem where I accidentally loaded maybe 3 at once and wasn' abLe to remove the clip. I removed the scope and had to take a thin razor and cut the pellet that was stuck halfway between the barrel and clip. I've never dropped my gun or scope. Now every time I go to shoot i can't seem to get it sighted. When I go to sight it in I'll shoot 8 shot groups before making adjustments and half the time my groups are real tight and other time the group are dollar size group.

Is there something wrong with my gun or something? It's been very frustrating.