diff -r 8a364deb0225 Lib/argparse.py
--- a/Lib/argparse.py    Thu May 02 10:44:04 2013 -0700
+++ b/Lib/argparse.py    Wed May 08 15:15:30 2013 -0700
@@ -136,6 +136,12 @@
         setattr(namespace, name, value)
     return getattr(namespace, name)
 
+def is_mnrep(nargs):
+    # re like string, {n,m}
+    try:
+        return _re.match('({\d?,?\d?}.?)',nargs) is not None
+    except TypeError:
+        return False
 
 # ===============
 # Formatting Help
@@ -581,6 +587,8 @@
             result = '...'
         elif action.nargs == PARSER:
             result = '%s ...' % get_metavar(1)
+        elif is_mnrep(action.nargs):
+            result = '%s%s' % (get_metavar(1)[0], action.nargs)
         else:
             formats = ['%s' for _ in range(action.nargs)]
             result = ' '.join(formats) % get_metavar(action.nargs)
@@ -2195,6 +2203,10 @@
         elif nargs == PARSER:
             nargs_pattern = '(-*A[-AO]*)'
 
+        # n to m arguments, nargs is re like {n,m}
+        elif is_mnrep(nargs):
+            nargs_pattern = '([-A]%s)'%nargs
+
         # all others should be integers
         else:
             nargs_pattern = '(-*%s-*)' % '-*'.join('A' * nargs)