diff --git a/examples/assembly/assembly.py b/examples/assembly/assembly.py
index 31984543a..ec1bb7e9f 100644
--- a/examples/assembly/assembly.py
+++ b/examples/assembly/assembly.py
@@ -131,6 +131,8 @@ if __name__ == '__main__':
     parser.add_argument('--generate', action='store_true')
     parser.add_argument('--run', action='store_true')
     args = parser.parse_args()
+    if not args.generate and not args.run:
+        parser.print_help()
 
     if args.generate or args.run:
         model = assembly_model()
diff --git a/examples/custom_source/source_ring.cpp b/examples/custom_source/source_ring.cpp
index 4b90f801a..b87afbd17 100644
--- a/examples/custom_source/source_ring.cpp
+++ b/examples/custom_source/source_ring.cpp
@@ -10,9 +10,8 @@ class RingSource : public openmc::Source
   openmc::SourceSite sample(uint64_t* seed) const
   {
     openmc::SourceSite particle;
-    // wgt
+    // particle type
     particle.particle = openmc::ParticleType::neutron;
-    particle.wgt = 1.0;
     // position
     double angle = 2.0 * M_PI * openmc::prn(seed);
     double radius = 3.0;
@@ -22,7 +21,6 @@ class RingSource : public openmc::Source
     // angle
     particle.u = {1.0, 0.0, 0.0};
     particle.E = 14.08e6;
-    particle.delayed_group = 0;
     return particle;
   }
 };
diff --git a/examples/parameterized_custom_source/parameterized_source_ring.cpp b/examples/parameterized_custom_source/parameterized_source_ring.cpp
index a334666ed..e70dc8bb1 100644
--- a/examples/parameterized_custom_source/parameterized_source_ring.cpp
+++ b/examples/parameterized_custom_source/parameterized_source_ring.cpp
@@ -34,9 +34,8 @@ class RingSource : public openmc::Source {
     openmc::SourceSite sample(uint64_t* seed) const
     {
       openmc::SourceSite particle;
-      // wgt
+      // particle type
       particle.particle = openmc::ParticleType::neutron;
-      particle.wgt = 1.0;
       // position
       double angle = 2.0 * M_PI * openmc::prn(seed);
       double radius = this->radius_;
@@ -46,7 +45,6 @@ class RingSource : public openmc::Source {
       // angle
       particle.u = {1.0, 0.0, 0.0};
       particle.E = this->energy_;
-      particle.delayed_group = 0;
 
       return particle;
     }