Question about Lube on Case

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c-ross
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Question about Lube on Case

Post by c-ross » Sat Apr 10, 2021 11:08 pm

Went shooting today and was trying to develop a load with a new bullet. I am using a Brooks Creedmoor bullet seated .59 into the case, which is just shy of the final driving band. Average case length is 2.088 inches. What I noticed that there was a ring of lube at the end of each case. I had not seen this with other bullets. My question is what is causing this. Thanks
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desert deuce
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Re: Question about Lube on Case

Post by desert deuce » Sat Apr 10, 2021 11:57 pm

Sounds like you are shooting a 45-70 with Remington Unprimed to start with cases.

See it frequently, does not seem to adversely affect accuracy.

What is causing it could be several things, among them case length less than chamber length.
Sometimes you get the chicken, and sometimes you get the feathers!

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c-ross
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Re: Question about Lube on Case

Post by c-ross » Sun Apr 11, 2021 7:03 pm

Correct RP brass. All had been shot several times. Since I had not seen this with the Lyman Postell bullet. I thought maybe that it may have been due the last driving band is reduced on the Creedmoor. I never thought about case length. If it does not affect accuracy then it is all good.

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desert deuce
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Re: Question about Lube on Case

Post by desert deuce » Sun Apr 11, 2021 11:58 pm

I had/have, a bunch of RP 4570 new brass. Usually runs about 2.080". Yes I see the lube ring on the front rim of these cases.

Stretched a bunch to 2.105", don't see a difference in accuracy and still see the lube ring. (Guessing my chamber is longer than 2.105")

But, I have no plans to stretch the brass further. What I do worry over is the outside of the case getting smoked upon being fired. That tells me that case needs to be annealed.

Seems the largest detriment to accuracy is usually the shooter and that is where I focus my attention. :D
Sometimes you get the chicken, and sometimes you get the feathers!

mdeland
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Re: Question about Lube on Case

Post by mdeland » Tue Apr 13, 2021 1:36 pm

I've nibbed out (stretched) my brass to fit the chamber length and after several firings it gets shorter again, around 2.085 . I still don't know why it happens. Perhaps annealing more often would be a remedy but I've not tried it.

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