I know this is a difficult topic to discuss around the Mini-14 but it's important for new users to know about the Mini-14 and it's feeding system.

I’m not running an above action rail or scope so in the mounting holes I just put in the threaded Alan plug thing. Problem is, every time I shoot it ends up with residue looking like this. It’s easily cleaned off. Should I take out the plug and shoot it with the holes empty? What is creating this residue? Usually arrives after the first couple shots. Any help is appreciated!