make sure you arent missing any screws from your grip frame, the 2 that hold it onto the body. ive seen alot of kids lose one of those screws and the body separated from the frame enough that the sear wouldnt catch. also, make sure you remembered to put the valve pin, spring, and pin guide back in last time you took it apart. and another possible source could be the hammer o-ring or physical wear on the hammer or sear. if none of that fixes it, i suggest you throw that gun in the trash
