I just got back from the local mom and pop gun shop and picked up some 7.62 ammo for my M1a National Match. It was being sold as Military surplus Ammo. It is marked FNM-83-13 and from the research Ive done I've determined that it is old Portuguese ammo. The problem is that some of the brass appears corroded in spots (see pictures). Do you guys think it is safe to shoot this stuff or should I toss it?