.htaccess extensionless url and 301 redirect loop - apache

Question

I have spent count-less hours trying to develop a good .htaccess to offer extensionless urls for SEO purposes. Almost every modern website I see has extensionless URL's and being a fairly new site I want to take this approach.
I have been able to successfully convert the site, using .htaccess, to extensionless. For example:
example.com/page.php will become example.com/page1 in the URL
HOWEVER, existing pages that are the same location (such as contact.php page) will do a LOOP when doing a 301 redirect. So, for example, so that a search engine doesn't think /contact.php and /contact are two different pages, the existing indexed /contact.php has a 301 redirect to /contact
However, the /contact url pulls its data from /contact.php behind the scenes and .htaccess knows this and then wants to apply the 301 redirect again to the behind the scenes /contact.php to /contact causing a loop. I cannot figure out how to stop this.
Bottom line is that I want a 301 redirect from /contact.php to /contact with /contact in the URL reflecting the contents of /contact.php physical file.
Here is my .htaccess to works well except for pages that have 301 redirects.
I'm also interested in any other issues you may see in my .htaccess :)
.htaccess
Options -MultiViews
Options +FollowSymLinks
RewriteEngine on
RewriteBase /
## 301 Redirects
# 301 Redirect 1
RewriteCond %{QUERY_STRING} ^$
RewriteRule ^contact\.php$ /contact? [R=301,NE,NC,L]
## Exclude appropriate directories from rewrite rules ^(blogsphere)
RewriteRule ^(blogsphere) - [L]
## Unless directory, remove trailing slash
# If requested URL ending with slash does not resolve to an existing directory
RewriteCond %{REQUEST_FILENAME} !-d
# Externally redirect to remove trailing slash
RewriteRule ^(.+)/$ $1 [QSA,L]
## Redirect external .php requests to extensionless url
# Any type of POST/GET should be a condition so that it doesnt rewrite without that data (end fileames in submissionscript)
RewriteCond %{REQUEST_URI} !^/([a-z-]+)\-(submissionscript)(.*)$
#Request has to end in .php
RewriteCond %{THE_REQUEST} ^(.+)\.php([#?][^\ ]*)?\ HTTP/
RewriteRule ^(.+)\.php$ $1$2 [QSA,L]
## If it is not a directory then internal resolve request to end with .php for extensionless php urls (/page will internally resolve to /page.php)
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^((?!(\.|\.php)).)*$ $0.php [QSA,L]

Answer 1

Have it like this:
Options -MultiViews
Options +FollowSymLinks
RewriteEngine on
RewriteBase /
# skip blogsphere directory for rewrite
RewriteRule ^(blogsphere) - [L]
## Unless directory, remove trailing slash
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{THE_REQUEST} \s(.+?)/+[?\s]
RewriteRule ^(.+?)/$ $1 [R=301,L]
# remove .php extension from URL - external redirect
RewriteCond %{REQUEST_URI} !^/([a-z-]+)-(submissionscript)(.*)$
RewriteCond %{THE_REQUEST} \s/+(?:index)?(.*?)\.php[\s?] [NC]
RewriteRule ^ %1 [R=301,L,NE]
# internally rewrite a file to file.php
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{DOCUMENT_ROOT}/$1.php -f [NC]
RewriteRule ^(.+?)/?$ $1.php [L]