Did my first cleaning today, quite a bit of black stuff came out! Noticed there is very a small ding on the outside of the barrel, I'm assuming this shouldn't make a difference since it's on the outside? Also, some of the nitron finish is already wearing off already on the slide rails where I assume there is metal on metal contact, should I put some extra grease on it and do I need to worry about rusting? I just used G96, is that sufficient or do I need a separate oil to lubricate?