Had a MONGO jam at the range yesterday. One of the 170gr FMJ Prvi rounds shed a primer, which then went up ABOVE the bolt carrier on Liberty.
Close the stock, SLAM on the ground multiple times until the live round cleared the chamber. That left the BC in a partially rearward position.
Fortunately MikeDaddy had a screwdriver and I was able to use it as a punch, to knock the BCG forward. Removed the upper and STILL had trouble moving the BCG but when it did move, that squashed flat primer fell right out.
That makes about 15 of these that have shed primers so far, out of a case of 1,000.