Gentlemen, here's a 30-06 case that I've never seen. What is different about it is the circular groove around the primer. This makes me think of the cases made for rifles that use a tubular magazine and the groove is to catch the pointed tip of the bullet from contacting the primer. As you can see it's an RA 45 which I presume to be Remington Arms 1945. Anyone have any information on this?