The round on top is a 300 RUM. There was 18 other ones just like it in my newly purchased box of ammo. The round on the bottom is a 300 WM sized to the length of a 300 RUM. The bad round fit into my rifle but I could tell something was wrong. I normally don't look at every round out of a factory box of ammo before I put in my rifle. May be I should start. What I am wondering is if the round on the bottom in the picture was fired out of a 300 RUM would there have been problems? What do you guys think?