It's a mistake! I have a couple of .223 rounds that look similar. I can't recall at the moment what I did to mess them up. It may have happened when I tried to chamber a round (tap, rack, bang) when the spent casing failed to eject; or I had the seating die set incorrectly, but I keep them on hand to remind me to PAY ATTENTION to what I'm doing when reloading.
Or, is it this?
I know the case is a necked down 50 cal, I think it’s a 22 bullet but I can’t find the name for the cartridge, but it’s said barrel life for this caliber would only last a hundred rounds or so
What I posted came from a thread on Long Range Shooters' Face Book page. That's the best I can do.
It's a joke. It's a modern implementation of the .22 Eargesplitten Loudenboomer which itself was something of a joke. It's not an original Eargesplitten since it's on an unbelted case and the shoulder angle is so shallow. The original Loudenboomer was made basically as a joke with a tongue in cheek academic question over to one side. Roughly estimating, barrel life would be on the order of around 25-50 rounds on a .50BMG case necked accordingly and around 150-300 rounds if done from a .378Weatherby case. Many people have made novelty dummy rounds like that. I used to have one that an old timer friend of mine made me that was a .25-20 case stretched to almost double normal length with a .505gn .458" cast wide flat nose in it.
Looked a lot like the one on the right.
LOL! Was the old timer a retired Navy pilot, per chance?
That sounds about right, anyways I appreciate the feedback!