What caused a torn case?

[Jons999]

Was out at the range to day with my M4. I put about 300 rounds through the gun flawlessly, then i had a misfire, i pulled the charging handle back to chamber another round and it only when halfway in. I removed the upper reciever and bolt and found an empty case still in the chamber. My first thought was that the chamber was dirty and the case stuck, but when i sent the cleaning rod down the barrel the case fell right out without any effort. I've had stuck cases tear the rim before but this case was literally torn right in the middle. After clearing the stuck case i put another hundred rounds down range without any problem so im assuming this is just a defective round, anyone see this before? It is Federal American Eagle 5.56, which i believe is military over-run m193. Case is headstamped LC 05.

[Scott Vandiver]

I would suspect bad case or bad case and a little over pressure. The case falling out after you field stripped it could be from cooling down. The case is thinner than brass, so it will cool faster than the chamber.

[Knowledge]

Is it chambered for 5.56 or .223?

[Jons999]

5.56 chambered Del-Ton upper, i know, not the greatest but havent had any other problems. I assumed it was a bad case but was looking for confirmation as i have never seen that kind of failure before.

[Pokeguyjai]

5.56 chambered Del-Ton upper, i know, not the greatest but havent had any other problems. I assumed it was a bad case but was looking for confirmation as i have never seen that kind of failure before.

The issue with Delton guns is that they are kit guns, meaning that the barrel could be from anyone. So if there are markings on the barrel, they could be unreliable. Meaning 5.56 might still be .223, as is the case in DPMS guns.

But XM is lake city rejects, so chances are it is the ammo.