https://www.facebook.com/senatordonnelly/posts/516841138348779
Posted on his Facebook, and I encourage you all do to the same, because it looks like his page is being dominated by anti-gun liberals at the moment.
Edit: My post has been taking down.
Are you posting to his timeline? I've seen others also complain about their comments not showing on his facebook, but I've commented multiple times under HIS topics and they've always stayed. It is probably a security setting so individual posts don't fill up his page and bump down his headlines. I suggest trying to comment under his headlines or topics.