How To Fix Sticky Nozzle/Bolt Ksc M4 / KWA LM4, Causing Missfeed

When loading nozzle (bolt) stick in the chamber (hopup dial house) this cause missfeed. And some times break the nozzle spring. So what i do is sanding chamber with light sand paper, i use number 360.

Sanding carefully, always checked if nozzle already has smooth contact with chamber before apply more sanding.
Steps:
Light sand - check - light sand - check - etc.. until it wont sticky anymore

Last step dont forget to polish the surface with metal polishing to smoothen surface.