diff --git a/M2/Macaulay2/e/mutablemat-defs.hpp b/M2/Macaulay2/e/mutablemat-defs.hpp
index ee5c76aa00c..b41e74a8d01 100644
--- a/M2/Macaulay2/e/mutablemat-defs.hpp
+++ b/M2/Macaulay2/e/mutablemat-defs.hpp
@@ -518,8 +518,7 @@ class MutableMat : public MutableMatrix
                 n_cols() - 1);
           return 0;
         }
-    MutableMat* result =
-        new MutableMat(*this);  // zero matrix, over the same ring
+    MutableMat* result = makeZeroMatrix(rows->len, cols->len);
     MatOps::setFromSubmatrix(getMat(), rows, cols, result->getMat());
     return result;
   }
@@ -534,8 +533,7 @@ class MutableMat : public MutableMatrix
                 n_cols() - 1);
           return 0;
         }
-    MutableMat* result =
-        new MutableMat(*this);  // zero matrix, over the same ring
+    MutableMat* result = makeZeroMatrix(n_rows(), cols->len);
     MatOps::setFromSubmatrix(getMat(), cols, result->getMat());
     return result;
   }
diff --git a/M2/Macaulay2/tests/normal/mutmat.m2 b/M2/Macaulay2/tests/normal/mutmat.m2
index d7ee8dcc57c..7e9ab1d6890 100644
--- a/M2/Macaulay2/tests/normal/mutmat.m2
+++ b/M2/Macaulay2/tests/normal/mutmat.m2
@@ -72,3 +72,8 @@ assert(ring mutableMatrix(ZZ/101, {{1,2,3}}) === ZZ/101)
 M = mutableMatrix {{1, 2, 3}, {4, 5, 6}}
 assert Equation(target M, ZZ^2)
 assert Equation(source M, ZZ^3)
+
+-- issue #997
+A = mutableMatrix {{10}}
+B = submatrix(A, {0}, {0})
+assert(hash A != hash B)