Since this is an AK building thread, it seems like an appropriate place to ask a question about the riveting of AK's.
Is there a wide variation in the quality of the rivets used to build AK's? Are the rivets heat treated or tempered in any way?
I'm asking this because I've just returned 2 AK's where the rear trunnion rivets bent backwards bad enought to cause the rear trunnion to separate slightly from the receiver.
This occurred on the IO Inc CASAR. Twice--on 2 separate rifles.