Tom G
posted this
16 November 2020
I wouldn't be too concerned with the angular ding in the case below the shoulder. It looks like it's been shot in an AR and banged off of the deflector on the side of the action during ejection.
It's not uncommon to find brass that is damaged in an AR. The ring on the neck/shoulder junction is serious. With the advent of very short barrels on AR's,, the gas port it not very far in front of the chamber. This results in the gun going out of time when the bolt starts to move backwards to eject the shell. With the gas port too near the chamber, it lets the gas come back to the bolt to early and it will try to eject the shell while there is still pressure in the chamber. This puts a lot of strain on the neck as the shell is being pulled back while the neck is still tightly held against the chamber neck area. This problem can also be caused by running a too light buffer in the gun too.
That ring is also on the inside of the case neck and it might be a stretch mark on the brass. I can see the thickness of the neck from the photo and it does not look like the neck is thinned in that area as would be found from a stretch mark. That is puzzling to see.
It might be that the AR rifle that the case was fired in has a timing problem and is damaging brass. "Might" being the operative word here.
Peter, you need to find some undamaged brass and shoot it only in your Howa and see if it is making the mark on the brass or not. If it does, there's a problem with the chamber in the gun. If not it's a problem with trying to use brass that has been damaged before use in your Howa. You may have to keep the brass segregated between the two guns from now on. Picking up range brass is not a good thing unless you know what happened to it before you picked it up.
Until you determine which gun is making the ring on the cases, it is very hard to figure out what is going on here.
Tom