What causes this and would you reuse the brass?

[AKG]

If you're around the 200 round mark I'd suspect carbon ring as a couple others suggested.

 

[Mike D Texas]

If you're around the 200 round mark I'd suspect carbon ring as a couple others suggested.

Carbon ring would cause pressure signs on every round fired, not just a few random ones.


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[AKG]

Carbon ring would cause pressure signs on every round fired, not just a few random ones.


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Misread one of his comments, thought he had said 4 of the last 40 had the issue rather than the 4th of 40 and thought he might have just started having the problem.

 

[GreyBeck]

After a through clean/de-oil and inspection all seems fine. I cycled multiple rounds without firing. No swipe marks, maybe a few scuff on the shoulder which may just be from the mag feed on soft Hornady brass. Ran 5 factory and 5 handloads - all were fine. Zero signs of pressure. It seems my exuberance in oiling was the culprit and/or a hot round too - the mag box was greasy at the bottom and along the sides. Thanks again - the article on pressure signs was helpful. Still saving brass. Will prob toss this one just to be safe.

 

[SDHNTR]

I own a McWhorter. Part of their schtick is they provide load data for a specific recipe for handloaded ammo.

Are you the original owner? Is the chamber cut to SAAMI or some custom dimensions and throated to shoot a specific bullet?

 

[100percent]

Call Allan!!! It will matter not whether you’re the original or tenth owner, he will help you get it sorted out asap.

 

[GreyBeck]

I am the original owner. Have all the load data and handloads they did the load development with. All is well now it seems.

 

[35WhelenAI]

Glad you found the culprit, Occam's razor.

 

[pods8 (Rugged Stitching)]

Blown primer with extractor mark! Definite pressure signs. I’d have to inspect webbing and measure pocket to see if reusable.

I've blown a few primers over the years in reloading, I you can almost guarantee that primer pocket is gone.

Also in general some factory ammo is loaded hot enough the brass is worthless for reloading because the primer pockets get stretched out off the bat. Buddy had that happen with some factory 300wsm ammo he had planned to reload.

 

[Lawnboi]

After a through clean/de-oil and inspection all seems fine. I cycled multiple rounds without firing. No swipe marks, maybe a few scuff on the shoulder which may just be from the mag feed on soft Hornady brass. Ran 5 factory and 5 handloads - all were fine. Zero signs of pressure. It seems my exuberance in oiling was the culprit and/or a hot round too - the mag box was greasy at the bottom and along the sides. Thanks again - the article on pressure signs was helpful. Still saving brass. Will prob toss this one just to be safe.

I’d toss anything suspect. Usually when you see and feel pressure Ie stiff bolt lift, ejector swipe, primer leakage, the case has expanded beyond the rest of your cases and may or may not still be usable. For a few bucks it’s worth it to pitch it, and not deal with the head scratchers down the line.