There was once this Russian made Baikal MP-153 that used to work. One day it stopped loading new shell in chamber. After multiple dissassembly-assembly and careful inspection no-one could find the reason for the sudden lack of operation. Then gun was shot around 1000 rounds by then and it was no more than 6 months old and clearly under warranty so it was sent to the dealer.
I’ve never sent a gun with courier company before so I called the day the gun should have arrived at the dealer. “It’s the Baikal that shoot only full auto right? We received it yesterday” was the answer I got. Apparently they were unable to fulfill my request if they could just combine the faults of these two Baikals after mine have arrived. I could not help thinking about full auto shotgun. Usefulness 0, but such fun.