Went to the range with a buddy of mine today and shot his brand-new Sig SCM 5.56. We were using unknown 5.56 ammo and Federal AE .223. Both ammo ejected with dents/scores in the brass, some with multiple dents/scores, and the rims were flattened slightly on one side. Not just some of them, all of them. I ran the same ammo through my AR, no problem. The dents/scores shown on the attached crappy photos aren't even the worst of them. Any idea what's going on here? Thanks.