If you use Google Webmaster Tools and expect to submit a feed as the source for a sitemap of your blog or website, you should use your site's original feed, and not your FeedBurner feed, for the sitemap to work properly.
For Blogger users, the following general feed URL format should always work:
http://mybloggerblog.blogspot.com/feeds/posts/default?redirect=false
For WordPress FeedSmith plugin users, use this URL format:
http://www.mywpblog.com/?feed=rss2
For all other platforms, other feed URL variations that are not redirected are what you need to provide.