A few years ago I came across several hundred rounds of Guatemalan 5.56. really cheap. It shot OK and was boxer primed so after I shot it, I cleaned and bagged the brass for a rainy day. Well, that rainy day was today. I had a hundred 55 gr fmjs that I wanted to load up for practice ammo. I saw that bag of Guatemalan brass on the shelf and decided to use it for practice ammo.
As I started sizing the brass it felt like the depriming took more effort to do than usual for .223 and after less than 10 rounds, I broke the decapping pin. I put a new pin in and started again. Three more cases and pow, another broken decapping pin. Now I'm thinking WTF? I suspected that I'd bent the rod that the sizing ball connects to. I replaced the pin again and tried to straighten out the the rod. I tried again and broke another pin!
I looked closer at the cases and the flash holes looked small. I compared the cases to some Lake City and Federal brass and found that they were much smaller than the holes on NATO and commercial cases and the decapping pins were breaking by pushing through the flash holes.
The lesson I learned tonight is that all 5.56 cases are not created equal.
Anyone want 200 pieces of once-fired 5.56 brass? Free. All you pay is the shipping.
Note: If you are Guatemalan or are friends with any Guatemalans, or are a Guatemalan sympathizer, I don't actually believe ALL Guatemalans are stupid, just the ones who design their 5.56 ammo.