Get posts between custom dates

First, you have to store your dates in a form that sorts properly mathematically. Unix timestamps will do that. The only human-like calendar format that does it is YYYY-MM-DD. You have your dates saved backwards.
Assuming you store as YYYY-MM-DD, then this should work:

$args = array(
  'meta_query' => array(
     array(
        'meta_key' => 'ows_schedule_field-date', 
        'meta_value' => array($date_one,$date_two), // both dates YYYY-MM-DD
        'compare' => 'BETWEEN'
     )
   )
)
$posts = new WP_Query($args);