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Posted: 7/4/2010 6:56:29 AM EDT
| Just wondering if any case prep is needed for new brass. Mine is Lake City if that matters. Thanks. |
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i had the same basic question.
http://www.ar15.com/forums/topic.html?b=6&f=42&t=316604 |
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New brass means it hasn't been fired.
Doesn't mean it's ready to load. 
New Win 7.62 x 39 brass. See the deformed necks in the lower cases? Some here will just load it as is, but the case length will not be consistent, and the case mouths dented and out of square with the case. What I do, size, tumble in corn cob to remove the lube, trim and debur. Now cases are ready to load. |
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I run them through a Sinclair neck expander, originally designed for neck turning prep. This uniforms the case neck tension and makes the mouth perfectly round.
Afterwards I use mt Giraud trimmer to uniform case length and impart a chamfer and deburr. The chamfer and deburr will have to be done manually if you don't have a three angle power trimmer. The case length is already spec from the maker, trimming just makes it more uniform. It can be skipped on the first firing if you don't have a power timmer. The deburring and chamfer can't be skipped, all new rifle cases require it. If you are going to uniform primer pockets and remove the flash hole burr now would be the time for that too. Otherwise, prime and load. |
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Unfortunatly you should treat new brass like used brass,full lenght resize to your chamber or guage then trim it for uniformity.
If you want accuracy the full case prep is the way to go,especailly for new brass... A lot of case prep only has to be done once so it is worth it !!! I hate case preping and would not do it if I did not have to 
John |
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You probably just bought some of that new offering by MidwayUSA, 500 new pieces of 5.56 LC for $79. NO CRIMPED PRIMERS to mess with. YES!
I bought 1,000 pieces and all came in very nice, but ugly after annealing. I resized 'em in a Dillon full-length die on a Redding T-7 press. Trimmed, chamferred and deburred in a Giraud power trimmer. Deburred the flash holes with a cordless drill. Tumbled in walnut media for a few hours. Then inspected the primer pockets for stuck media. Did not bother with cutting into perfectly nice primer pockets. That's it. Next will be to start priming all of them with Fed 205M and Rem 7 1/2. All will be used in my RRA varminter, nothing goes in my custom CZ bolt gun but Lapua brass. I consider this LC brass as my second-best brass behind Lapua: Winchester is third and then PMC/Remington. |
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As a general rule, yes, it is required, sizing and trimming. New LC brass does not require removal of the primer crimp ring or cleaning. Once fired LC brass is usually from a military source and does require crimp ring removal and usually cleaning.
The downside of new LC brass is that it has not been pressure tested like the once fired. That downside and the additional cost of the new brass is considered acceptable to some reloaders because of the aggravation of the crimp ring removal process. |
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