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Posted: 9/13/2016 1:07:02 PM EDT
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So, recently I posted a thread about messing up $200 worth of my 300 RSAUM brass by neck turning them too thin. Well, turns out that I didn't because a $60 redding bushing neck sizer die and a $12 forstner bushing makes them functional again. If not even better.
But, my brass is shrinking. 3rd firing after neck only sizing and my brass shrunk from 2.003-2.005 to 1.975 roughly. They haven't been trimmed. Is this normal? Will it stop? I am certain when I full length size them again, I will get some growth but I honestly don't know when that will be. And last question, how short is too short when the trim to length is 2.005 (same as 308 win)? |
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http://www.saami.org/PubResources/CC_Drawings/Rifle/300%20Remington%20Short%20Action%20Ultra%20Magnum.pdf SAAMI lists a minimum of 1.995" trim length. I dont know about your cartridge, but in general, light to medium range power loads expand the case body outward. This pulls the shoulder and neck back, making the trim length shorter. If you can get enough neck tension with the short neck, you may be ok?? You want the neck to expand a minimum of .002" after seating a bullet. Neck wall thickness should not be thinner than .010" from what i read?? If a single shot rifle, then lighter neck tension is ok. |
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Good to hear that you saved your brass. Would a Lee collet neck size have worked too. Probably don't make one.
I wouldn't worry about your case length although that was probably more shrinkage than usual. I don't think they will get much shorter. As long as you have decent neck tension you should be fine. I am judging this on the fact that you are using neck only sized brass which leads me to believe that you most likely are either shooting slow fire or single shot and using a bolt action rifle. Motor |
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Yes, shooting them in a bolt gun. They are on their 3rd firing with neck only sizing. Neck tension is very good and consistent and I annealed them just in case.
I just loaded up 54 of them today in different flavors of bullets and loads. Guess I will see how they do in the long run. Every piece has about 6 firings on it and I have never had a split neck or other brass failure that wasn't due to my failure to lube the case before full length sizing it. And lee didn't make a die for it. Redding was the only one that made a bushing style die. |
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