questions about once-fired brass (223)

[nidm]

hi, folks,

two questions about the brass in the attached pictures.

The first picture is two brass side by side. the left-hand side is LC 15 I picked up at range, the right-hand side is PMC. Why the upper side of Lake city one is so discolored

The 2nd picture is the same PMC 223 brass I fired through a AR-15. Almost all the PMC 223 brass in the batch has the small dent. wondering what cause it?

thanks

nidm

[wpage]

During extraction brass will somtimes hit the reciever on the way out and leave a mark

[elpaisa1]

The discoloration is caused during annealing. It's normal and a good thing. As far as the dent. That could have been cause doing extraction.

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[elpaisa1]

Caused during extraction.

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[diveRN]

Common. Nothing to worry about unless creased badly or cracked.

Go to :42 in this video, shows how it hits the receiver on the way out.

[kcheung2]

Wow, a legit "that discoloration is annealing, and it's a good thing" question.

[nidm]

Guys,

btw, I tried to deprime the Lake City brass last night, but failed. I used RCBS full length sizer die with an expander-decapping unit. It works fine with PMC brass, but cannot push the Lake city prime out, probably due to the crimp.

[OpenSightsOnly]

Yeah there is a crimp.

You need to adjust the depth of the decap assembly.

If your RCBS FL die has the thicker decap pin then you are good to go and will decap crimped primers with ease.

[AGGRO]

Lee universal decapping die

[Metal God]

The discoloration is in fact anneal marks . The interesting thing is that the PMC is likely annealed the same . All cases are annealed several times as they're drown out to size during the manufacturing process . The difference is military contract 5.56 NATO is required to have the anneal marks when finished while most commercial cases are tumbled enough after to remove the anneal marks .