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Thread: Brass Failure
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06-04-2018, 19:26 #1
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- Oct 2016
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- 59
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Brass Failure
PMP Pro-Amm 150gr 7x57
Shot this box of Pro-Amm ammo yesterday, I have no idea how old the ammo might be, box indicates lot 004
I never use 150grainers, only use 173-175grainers, anyway used this for range practice, accuracy was not bad but 8 of the 20 rounds showed visible failure on the shoulder area. Anybody that can enlighten me why this happened. I reload 99% of my ammo and have not experienced this before but this is PMP factory ammo.
Thoughts?PMP ProAmm 381 (Copy).JPG
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06-04-2018, 22:23 #2
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- Aug 2012
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- Stella
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Re: Brass Failure
Faulty brass, corroded brass, compromised powder (unlikely!), very tight chamber.
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15-04-2018, 15:44 #3
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- May 2017
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- Alabama USA
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Re: Brass Failure
In my opinion, brass failure due to deteriorating gunpowder in the case. You never stated exactly how old your ammunition is, but things like this start to occur around the ten year mark and occur progressively more frequently as gunpowder ages. I understand CIP has a ten year gunpowder stability requirement. Gunpowder is a high energy compound that is breaking down to a low energy compound, the day it leaves the factory. As it breaks down it outgasses NOx compounds, one of those is NO2, which is an aggressive oxidizer. Your brass is attacked by these compounds, and weakened.
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15-04-2018, 16:45 #4
- Join Date
- Oct 2016
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- 59
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- 140
Re: Brass Failure
I believe you are correct, I have no idea how old this ammo was but looking at the lot No. definitely older than 10 years. Interestingly enough I was present on the range when another shooter was putting lead downrange at a rate of knots with his M4 type carbine, I recognised the buff coloured PVC/Plastic bag the ammo came in, turned out to be military surplus from the eighties! unfortunately I didn't look at his spent brass to see the condition. Thanks for the feedback.
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