The pictures don't show any evidence of receiver failure. You can shoot with quite a bit of excess headspace and not have any safety issues UNLESS the case head is not properly supported. Case head support is marginal in any cone breech system. A defective case that blows out in any cone breech weapon will cause the damage shown. A seriously overloaded case will fail the same way and cause the same damage. Case head failures have occurred with Korean import surplus and caused the same damage in "perfectly good" USGI 03A3's and M1icon's. Prvi Partizan factory ammo has failed in the K-L-M area of the case and caused the same type of damage as what is shown. A similar failure would have caused a brittle low number receiver to shatter. The fact that this receiver did not fail is a credit to whoever made it.

I'm not a National Ordnance advocate, but to blame this failure on a poor quality National Ordnance receiver without evidence of receiver failure is irresponsible.

Resp'y,
Bob S.