I suggest you make sure you have a pretty good list of what you're selling, and then try to make it a package deal (otherwise you'll spend forever chasing down one box of this and one box of that.)
Notice the line above the list of rules. It is probably worth it to join with a 1 year membership rather than wait until you have 15 posts. The reason for this rule is to make it difficult for scammers to post fake items for sale..
I'd also suggest posting an Intro thread and participating on the forum and let the other members to get to know you. It will go a long ways in people feeling comfortable in doing business with you.
Disagree with above. Reloading is very personalized and lots rarely sell unless they are priced around 1/10 to 1/5 of real value. The best chance at selling as a lot is finding someone that buys up estates or collections for resale.
This is likely not the place for a new member to sell. The classifieds section is not a main focus of this forum like some others. People come here to discuss, not trade. If I were you I would use Texas Gun Trader. Some people have had bad experiences there but it's fine if you're smart about what and how you post.