diff --git a/openmc/data/angle_distribution.py b/openmc/data/angle_distribution.py
index 778139cc2ad..460ec3b174e 100644
--- a/openmc/data/angle_distribution.py
+++ b/openmc/data/angle_distribution.py
@@ -260,7 +260,7 @@ def from_endf(cls, ev, mt):
             for i in range(n_energy):
                 items, al = get_list_record(file_obj)
                 energy[i] = items[1]
-                coefficients = np.asarray([1.0] + al)
+                coefficients = np.insert(al, 0, 1.0)
                 mu.append(Legendre(coefficients))
 
         elif ltt == 2 and li == 0:
@@ -288,7 +288,7 @@ def from_endf(cls, ev, mt):
             for i in range(n_energy_legendre):
                 items, al = get_list_record(file_obj)
                 energy_legendre[i] = items[1]
-                coefficients = np.asarray([1.0] + al)
+                coefficients = np.insert(al, 0, 1.0)
                 mu.append(Legendre(coefficients))
 
             params, tab2 = get_tab2_record(file_obj)