Switching domain from HTTPS to HTTP

I recently launched a new site on an already existing domain, using new hosting. The previous site utilized HTTPS, the new site does not (just HTTP).

The problem I've ran into is that Google currently has the site indexed as HTTPS. The site is in WordPress, I've tried to 301 redirect HTTPS URLs to HTTP with htaccess (placing rules above the WordPress rules), with no success. The HTTPS version displays the security warning of course (as there is no SSL certificate) and then a 404 if you go past that.

Here is what the htaccess file currently looks like:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{SERVER_PORT} ^443$
RewriteRule ^(.*)$ http://%{HTTP_HOST}/$1 [R=301,L]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

I've tried other rules as well to redirect the traffic with no luck. Additionally, Google Chrome still redirects example.com to https://example.com, no amount of clearing cache resolves this issue. All other browsers work fine, www.example.com works as expected in all browsers.

Has anyone else experienced these issues when moving a domain away from HTTPS? Is there a standard way available to notify Google of the change?