In a small estate thing we bought last week we got around

120,000 rounds of once fired brass. In that batch of brass there were several of this strange case. I remember seeing a new brass that the front of the case separated from the base. I don't know if this is one of them but it looks like the pictures I have seen in the gun magazines. I don't know the reason for the base separating from the front of the case, but in the ad it did. I also don't know if this is that same case but the groove in the case is inside the case as well as the outside. Anybody know anything about this?