diff --git a/pyerrors/input/hadrons.py b/pyerrors/input/hadrons.py
index 4bdb177f..a9e220b9 100644
--- a/pyerrors/input/hadrons.py
+++ b/pyerrors/input/hadrons.py
@@ -85,15 +85,20 @@ def read_ExternalLeg_hd5(path, filestem, ens_id, order='F'):
 
     files = _get_files(path, filestem)
 
+    mom = None
+
     corr_data = []
     for hd5_file in files:
         file = h5py.File(path + '/' + hd5_file, "r")
         raw_data = file['ExternalLeg/corr'][0][0].view('complex')
         corr_data.append(raw_data)
+        if mom is not None:
+            assert np.allclose(mom, np.array(str(file['ExternalLeg/info'].attrs['pIn'])[3:-2].strip().split(' '), dtype=int))
+        else:
+            mom = np.array(str(file['ExternalLeg/info'].attrs['pIn'])[3:-2].strip().split(' '), dtype=int)
         file.close()
     corr_data = np.array(corr_data)
 
-    mom = np.array(str(file['ExternalLeg/info'].attrs['pIn'])[3:-2].strip().split(' '), dtype=int)
 
     rolled_array = np.rollaxis(corr_data, 0, 5)