diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 429bb9d5..fffedd82 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -7,6 +7,13 @@
 Changelog
 =========
 
+3.1.6 - 2022-03-27
+------------------
+
+**Bug fix:**
+
+- We fixed a bug in the dense sandwich product, which would previously segfault for very large F-contiguous matrices.
+
 3.1.5 - 2022-03-20
 ------------------
 
diff --git a/src/tabmat/ext/dense_helpers-tmpl.cpp b/src/tabmat/ext/dense_helpers-tmpl.cpp
index cd3bb5b3..a37b36a9 100644
--- a/src/tabmat/ext/dense_helpers-tmpl.cpp
+++ b/src/tabmat/ext/dense_helpers-tmpl.cpp
@@ -230,7 +230,7 @@ void dense_base${kparallel}(F* R, F* L, F* d, F* out,
         }
         F* L = &Lglobal.get()[omp_get_thread_num()*thresh1d*thresh1d*kratio];
         for (SIZE_T Cii = Ci; Cii < Cimax2; Cii++) {
-            int ii = cols[Cii];
+            SIZE_T ii = cols[Cii];
             %if order == 'F':
                 for (SIZE_T Rkk=Rk; Rkk<Rkmax2; Rkk++) {
                     SIZE_T kk = rows[Rkk];