Weird dents in case

[mudduck]

At the club match today one shooter was have some odd dents on case after they where fired. Not every case would have the dents after fired. We wiped camber out with patch on a mop thinking there had to be something in it but still coming out with dents. Best answer when could come up with case not expanding to camber walls and the gas was flow back and causing the dents. Brass was hornady 6.5 cm with five to seven firings on it neck sized. What y’all think

 

[Mark W]

Yep, I bet it’s a combination low pressure loads and work hardened brass.

 

[Dave M.]

Definitely appears to be lots of carbon on the shoulders. Did they start clean? How many times fired? What bullet and what power and charge?

 

[mudduck]

Definitely appears to be lots of carbon on the shoulders. Did they start clean? How many times fired? What bullet and what power and charge?

Not sure of load specs as wasn’t my rifle.

 

[M-61]

Definitely appears to be lots of carbon on the shoulders. Did they start clean? How many times fired? What bullet and what power and charge?

He said ..’five to seven firings’

 

[Ned Ludd]

I'm not saying that this is the definitive cause in this specific example, but low pressure loads can cause this. I believe it relates to failure of the neck to seal properly as you mentioned.

 

[Dave M.]

Not sure of load specs as wasn’t my rifle.

Ok. Just trying to see if we could discern if this was a very light load which might lead to gas blowby

 

[dskogman]

See this thread

Strange dent in fired case

I had a strange dent in a fired case today: I’ve had it once before and thought it was from bumping the shoulder too far although this time that was not the case. It is close to a max load in a 300 WSM with H4350. It was cooler today which may have contributed. The neck tension was also lower...

forum.accurateshooter.com

Reply 38 was the winner.

 

[searcher]

That appears to be gas blowby - but can be caused by a combination of factors - not just a light load. Excessive headspace between shoulder and chamber can make this happen much more pronounced with a light load. If his gun didn't do this before using the same load, I'm guessing he just pushed the shoulders back a bit too far and it allowed the light load to be more apparent than before.

 

[243winxb]

Link from bottom of this page. https://forum.accurateshooter.com/threads/strange-dent-in-fired-case.4016999/

 

[Dusty Stevens]

Very light charge. Stay away.