This is really a comment - I just can't post them yet...but Melanie's Answer is the correct one.
Keep in mind that gravity forms has nothing to do with the custom post type - you will have to create that yourself either via code or with a plugin.
To make a form entry post to a custom post type - from the Post Fields field types, add a "Post Title" field to your form. In the Properties tab of this field, you can set the initial status and a category for the added post. In the Advanced tab, you can set the post type to use (but only if the plugin Melanie mentioned is installed and activated).
And then...of course...you will have to handle displaying the custom post type posts on your blog...