diff --git a/lib/puma/const.rb b/lib/puma/const.rb
index 00291b96..cfa9d922 100644
--- a/lib/puma/const.rb
+++ b/lib/puma/const.rb
@@ -1,52 +1,16 @@
+require 'rack'
+
 module Puma
 
   # Every standard HTTP code mapped to the appropriate message.  These are
   # used so frequently that they are placed directly in Puma for easy
   # access rather than Puma::Const itself.
-  HTTP_STATUS_CODES = {
-    100  => 'Continue',
-    101  => 'Switching Protocols',
-    200  => 'OK',
-    201  => 'Created',
-    202  => 'Accepted',
-    203  => 'Non-Authoritative Information',
-    204  => 'No Content',
-    205  => 'Reset Content',
-    206  => 'Partial Content',
-    300  => 'Multiple Choices',
-    301  => 'Moved Permanently',
-    302  => 'Moved Temporarily',
-    303  => 'See Other',
-    304  => 'Not Modified',
-    305  => 'Use Proxy',
-    400  => 'Bad Request',
-    401  => 'Unauthorized',
-    402  => 'Payment Required',
-    403  => 'Forbidden',
-    404  => 'Not Found',
-    405  => 'Method Not Allowed',
-    406  => 'Not Acceptable',
-    407  => 'Proxy Authentication Required',
-    408  => 'Request Time-out',
-    409  => 'Conflict',
-    410  => 'Gone',
-    411  => 'Length Required',
-    412  => 'Precondition Failed',
-    413  => 'Request Entity Too Large',
-    414  => 'Request-URI Too Large',
-    415  => 'Unsupported Media Type',
-    500  => 'Internal Server Error',
-    501  => 'Not Implemented',
-    502  => 'Bad Gateway',
-    503  => 'Service Unavailable',
-    504  => 'Gateway Time-out',
-    505  => 'HTTP Version not supported'
-  }
+  HTTP_STATUS_CODES = Rack::Utils::HTTP_STATUS_CODES
 
   # For some HTTP status codes the client only expects headers.
-  STATUS_WITH_NO_ENTITY_BODY = {
-    204 => true, 205 => true, 304 => true
-  }
+  STATUS_WITH_NO_ENTITY_BODY = Hash[Rack::Utils::STATUS_WITH_NO_ENTITY_BODY.map { |s|
+    [s, true]
+  }]
 
   # Frequently used constants when constructing requests or responses.  Many times
   # the constant just refers to a string with the same contents.  Using these constants