Its Chinese Machine gun ammo. Canam was bringing these about 5-6 years ago. It came in 1000 rd crates, two spam cans of 500 rds. On the lid of the crate there was list of chinese machine guns and bullet deviation tables at certain distances. So this ammo is not the most consistent lot. I shot about a crate of this stuff and you get a plinking ammo at best. They all go bang, its new 2011 production ammo, just don't expect stellar accuracy. And yes it is corrosive.