diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b25c15b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*~
diff --git a/megawarc b/megawarc
index 17bf41f..20f0411 100755
--- a/megawarc
+++ b/megawarc
@@ -435,8 +435,9 @@ class MegawarcPacker(object):
     elif filename.endswith(".gz"):
       dict_id = None
       if "gz" not in self.megawarcs:
+        base = self.output_basename
         self.megawarcs["gz"] = {
-          "warc": {"file": open(base + ".megawarc.warc.zst", "wb")},
+          "warc": {"file": open(base + ".megawarc.warc.gz", "wb")},
           "json": {"file": gzip.open(base + ".megawarc.json.gz", "wb")},
           "tar": {
             "file": open(base + ".megawarc.tar", "wb"),