Effect of case mouth cracks

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  • Last Post 23 September 2018
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Eutectic posted this 23 September 2018

I was recently doing rapid firing lube testing in the 38 Special. This involves 100 rounds as fast as they can be fired at multiple targets to see if the lube will hold up. Since maximum accuracy was not required, only relative groups at 25 yards I used mixed cases fired perhaps 15 times with target loads. I got some fliers and each time I looked there a case mouth crack. The cases were inspected after loading and some cracks were found and pulled, the cases were on the way out. The cracks happened on firing, the result was predictable.

Yes the lube worked just fine. 

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John Alexander posted this 23 September 2018

Dumb question maybe but were the loads crimped? Heavily crimped? Is the crimp needed to shoot well but only to avoid bullet movement by recoil before their turn?

John

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Eutectic posted this 23 September 2018

Not a dumb question, minimal crimp to remove the bell. These are light wadcutter loads so a heavy crimp is not needed. I would expect a heavy crimp to perhaps show more effect.

The cracks I found after loading were small and right in the crimp zone.

This was the the Accurate 36 160W wadcutter so it has a nice crimp grove. I will be using a heavy crimp when I test them with +P loads and in the 357.

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