on the base of the pistol grip, there is a small screw (allen head, flat head or philips) if it is loose tighten it untill the griding stops and normal firing resumes, if it is really far in, loosen it off a bit
right i had a look at my gun the other day, and it seem this screw (motor height screw) seems to be missing.... guess i have found my problem here... any ideas where i can get a replacement screw from? should my local airsoft store supply them?
local airsoft store or even take the lower part (for the love of god not th whole gun) to a local DIY store and ask for a grub screw to fit that *point at the hole*
IIRC they are 1.5mm usually
a local airsoft shop is probably the best place to start