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New Brass Prep for Lapua Brand Brass

m1a convert

Sergeant
Full Member
Minuteman
Mar 29, 2003
287
4
Idaho Falls
I have read a lot of brass prep threads and it seems there is a wide latitude in what people do. I also see that some steps aren't done as often on Lapua brand brass because of it's quality. My understanding is that the flash hole is drilled not punched so that gets rid of a few required steps.

For ELR what prep work needs to be done for new Lapua brass? I am about to start prepping some .338 LM brass.
 
Lapua is punched. They just do a good job of it.

I would just run them over an expander mandrel if you have one, if not into the sizing die just enough to round out the neck, not far enough to actually touch the case body.

Or just load and shoot.
 
Lapua is punched. They just do a good job of it.

I would just run them over an expander mandrel if you have one, if not into the sizing die just enough to round out the neck, not far enough to actually touch the case body.

Or just load and shoot.
I have found that neck sizing definitely improves consistency on new Lapua brass. Nothing else I've tried made a measurable difference.
 
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I'll also chamfer the inside with a VLD tool and deburr the outside.
I do this to all my new brass and only have to do it once.
 
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I hit my last batch with an expander mandrel and then a light debur inside the neck. The debur likely isn't needed, but it looking at the case necks with a magnifier, there's a bit of inconsistency there (as you'd expect). Cleaning them up a little makes me feel better, but that may be the only real effect... ha ha
 
I run them over an expander ball, use a very shallow primer pocket uniformer that only makes contact if there is a very high spot, chamfer inside and out on the necks, and touch them with a flash hole deburring tool. Then just do primer, powder, and bullet. The primer pocket uniformer only removes material maybe 0.5% of the time, if at all, and the duburring tool maybe 5% of the time. I have them on a case prep center so it isn’t time consuming to do it the one time on virgin brass. After they’re all fired once, I find the shortest case, and use it to set my trim length I use for all the cases.
 
I generally run mine over an expanding mandrel, chamfer the neck and load. I have a batch of small primer 6.5cm that had raggedy flash holes on about 30% of the cases that had to be dealt with. Never hurts to check.