New Lapua brass

[Ned Ludd]

The main issue I have noticed with virgin Lapua brass over the years is that the neck tension (interference fit) is not consistent straight out of the box, specifically, 0.223 Rem and 0.308 Win Palma brass. Most of the cases are fine, but the necks of one or two out of every ten or so will be noticeably larger/smaller than the rest, which can cause excessive velocity variance and/or precision issues.

I first open up the all necks to a minimum diameter slightly larger than my final target dimension using an oversized expander mandrel (~-.001" under bullet diameter). I then size the necks back down using the appropriate diameter bushing for ~.002" interference fit with a FL resizing die. An appropriately adjusted die will not push the shoulders back at all on virgin brass. After these steps, I trim/chamfer as normal, load, and shoot it. In my hands, necks prepared this way are much more consistent than those of brass straight out of the box. I have used virgin brass prepped this way in competition on many occasions and it works very well.

https://www.sinclairintl.com/reload...ls/generation-ii-expander-dies-prod38807.aspx

https://www.sinclairintl.com/reload...inless-steel-expander-mandrels-prod33134.aspx

 

[Tim-o-thy]

I do the same exact as Bc'z

Run them through expander
Chamfer inside mouths
Load and fire
Full length size
Uniform primer pockets
Deburr inside flash-hole

I do sometimes deburr inside flash hole before the first firing.

You find this necessary even on lapua brass? I agree with lesser brass but never found the need to on lapua, should I find the need too?

 

[Zero333]

You find this necessary even on lapua brass? I agree with lesser brass but never found the need to on lapua, should I find the need too?

The least I would do is run the new brass through an expander to straighten the mouths and chamfer inside the mouths.

 

[Tim-o-thy]

The least I would do is run the new brass through an expander to straighten the mouths and chamfer inside the mouths.

I was referring g to the primer pockets

 

[Bc'z]

I was referring g to the primer pockets

I use a uniformer to clean my pockets when prepping.
Mostly muscle memory in my process.
Most of the lapua I've processed new I never touched bottom of pocket, a few I've cleaned up the corners a touch.
I've noticed they clean up a bit after firing a couple rounds.

 

[Zero333]

I was referring g to the primer pockets

I uniform primer pockets after the first firing for good measure. Even if the uniforming tool doesn't cut any part of the pocket, at least it will clean the pocket.