diff --git a/kbas/__main__.py b/kbas/__main__.py
index a91e2bc..54e8063 100755
--- a/kbas/__main__.py
+++ b/kbas/__main__.py
@@ -90,7 +90,8 @@ def get_morph_artifact():
     @bottle.get('/get/<cache_id>')
     def get_artifact(cache_id):
         f = os.path.join(cache_id, cache_id)
-        return static_file(f, root=app.config['artifact-dir'], download=True)
+        return static_file(f, root=app.config['artifact-dir'], download=True,
+                           mimetype='application/x-tar')
 
     @bottle.get('/')
     @bottle.get('/status')