Originally Posted by kalnaren
for the hop-up rubber.
I haven't touched an M16 hop-up for quite some time though (and even then it was in an L85), so you might have to do some googleing on that. I'm not sure how an M16 comes apart.
one more question, where can i buy a Completely new gearbox for my m16, and will it come with everything so all i need to do is get a professional to throw it in