My friend gave me a bunch of 7.62 NATO brass after shooting his FAL. While trying to full length resize the cases my die would only go down about 3/4 way and then get very tough. I ended up breaking the decapping pin and never getting full travel from the press. I have done Federal NATO and commercial cases with no problems whatsoever. Is it possible that some surplus ammo looks like brass but is steel inside? Should I cut one in half and see or shoul I just trash the casings. I think they were 147gr NATO surplus in a badolier, maybe Pakistani. Any thoughts?