so i got my new g&p m4 yesterday and i love it it was shooting 335fps and 22rps with a 9.6v last night when i opened it, i came to set the hop today and all i get is a horrible grinding sound from the motor like its not connecting with the gears properly ive adjusted the motor height and it doesnt turn in its highest position and it still does the grating sound as i wind it down even doing it 1/8 of a turn at a time. ive phoned proairsoft supplies and there happy to collect it and have their tech fix it its just a hassle for me i was wondering if anyone had any insight if i can fix it without having to send it back so i can still skirmish tomorrow. ive read that it might be the shimming of the gears in which case it has to go back because im not experienced with gearbox and dont want the invalidate the warranty on a £350 gun.