diff --git a/mrdna/segmentmodel.py b/mrdna/segmentmodel.py
index 9434d4be098fbf379ee73dc82493557722994e2d..cfacf7a29d61fa729c1fa93ccb82da2d737f6fa6 100644
--- a/mrdna/segmentmodel.py
+++ b/mrdna/segmentmodel.py
@@ -1811,12 +1811,10 @@ class SegmentModel(ArbdModel):
 
             beads_contours = get_beads_and_contour_positions(s)
             contours = [c for b,c in beads_contours]
-            contours = np.array(contours, dtype=np.float16) # deliberately use low precision
-            contours,ids1 = np.unique(contours, return_index=True)
+            contour_idx = np.array( np.array(contours)*s.num_nt * 10, dtype=np.int )
+            contour_idx,ids1 = np.unique(contour_idx, return_index=True)
             beads_contours = [beads_contours[i] for i in ids1]
 
-            assert( np.any( (contours[:-1] - contours[1:])**2 >= 1e-8 ) )
-
             ## TODO: keep closest beads beyond +-1.5 if there are fewer than 2 beads
             tmp = []
             dist = 1