Drupal front page blog entries custom sort order
You may add your custom field "sort_order" to the blog content type, then create a page view (/admin/structure/views/add) for the blog content (just like node does it in the "frontpage" view - you may even copy that view and restrict the nodetype to blog in your copy). 

Then change the "sort criteria" in the view to your sort_order custom field. 

Then you're done.