Guns are dangerous. Federal AE223BK Kaboom.

[HiggsBoson]

Derek, glad you're okay. Was this your first KB? I hope I will fare as well when I have a similar failure, which I assume is only a matter of time since I shoot a fair bit and use lots of different ammo of occasionally dubious provenance.

Just to admit, I do not know what the heat mark is from or why it is there, I just know I see it evertime I open my ammo. When I look at the picture a few posts up, I instantly noticed that the brass is a constant color and not the same as what I am used to holding/seeing.

Larry, from what I understand the discoloration you mention is caused by annealing which is done for reliability and accuracy (it serves to re-soften the brass at the case neck.) After reading up on it, several sources indicate that a lack of annealing on the cartridge can lead to case neck splitting...

What I have read seems to indicate that NATO-pressure ammo without annealing could be a contributing factor in a KaBoom. I could be wrong. If so, hopefully someone will correct me. ETA: Others have pointed out that lack of annealing can cause problems, but the annealing may not be apparent due to tumbling. Also, this case (no pun intended) does not appear to be split at the neck as is usually caused by lack of annealing, but rather a circumferential split.

Lake City XM193 has the heat marking where the brass necks down, at least all the Federal XM193 and white box Lake City XM193 I have does. Why does that not have the typical heat discolor I'm used to seeing?

All the XM193 (both F and otherwise) I have has annealing on the case-neck. I have on hand white and brown box "XM193F" as well as AE black box "XM193" from various lot #'s. All rounds I have so far examined show the annealing and LC 09 w/ NATO cross headstamp. Also, I believe annealing is called for in the original M193 spec (unable to verify this currently,) so I would be somewhat suspicious of any round claiming to be any variation of M193 and not having annealing. HTH