Good day everyone. I really don't want to sound like an idiot but I have to ask to find out.
Does anyone here know of a way to get the bolt to slide inside the bolt tube without a gritty sound? I've tried everything in my cleaning kit to get the gritty sound/feel and I can never get rid of the grit sound. I've tried everything I know,mutiple times with no luck.

Could it be because of the polimer serface of the interior of the tube?

Any one chime in here.

Sorry for the stupid question....