6 BR Sizing question.

[eitmsmf]

This is my first experiance with a 6br. I used a Redding comp neck die with a carbide expander ball for first sizing. I started with a .267 bushing. My questions are the 6br Lapua brass was 10 to 15 thou's long over the listed 1.550 trim length in the Sierra book. Is this normal for new brass? Also I seemed to have more uneven case mouths after sizing than I've seen with other Lapua brass. They were fine after trimming but I figured it couldn't hurt to ask. Thanks.

Shaun

 

[janderson0]

Few things, 6br Norma case should measure 1.560. You do not state what size neck dia your after. Most including myself will suggest you get rid of the expander, as with it it controls neck dia not the bushing.

Also I found that my cases shrank after first firing.

Jim

 

[billmo]

+ 1 Get rid of the expander ball. Bill

 

[expiper]

I usually trim my brass to 1.553-1.555 after first fireing and have never had em grow to 1.560 even with 50 reloads on em!!
OBTW + 2 for throw the expander over the hill ...just use a bushig .002-.003 smaller than your loaded round....Roger

 

[eitmsmf]

I got the length from the Sierra book but I think 1.555 sounds better. I was trying the floating expander ball for the first time. I liked the idea of not having to worry if I dent a case somewhere along the way. I also thought the expander would keep any runout on the outside of the case mouth as this is a no turn chamber. Thanks for the responses.

Shaun

 

[jb1000br]

If you are not shooting turned necks, you might want to keep the expander ball. Why force the unevenness to the inside and let it there?

The expander ball isn't your problem. I do not believe that a floating carbide expander ball is lengthening cases, no way. Overworking them will lengthen them though. Did you check how far you move your shoulder,headspace) upon sizing?

With a no-turn neck, I like a .268 TiNit bushing.

My 8x fired cases are ~1.560" using Harrells semi custom FL sizer and moving the shoulder about 1.5thou each time...with a follow-up drag across a floating carbide expander ball,though it barely kisses the inside of the neck)

YMMV,
JB