What neck chamber size?

[gt40]

What is the inside neck chamber size for a no neck turn Lapua brass for 6mm Norma BR?

I just seated a 90 grain match Berger bullet into a new Lapua 6mm Norma BR case. Before I seated it I miked 5 necks of the new unfired brass and they all measured .268 inches then I miked the neck of the seated case and it measures .269 inches. I hope I read the 2 different mikes correctly.

What should the neck in the chamber measure?

gt40

 

[Leeroy]

6br

G'day Gt40

My 6BR reamer is from PT&G and was a "No Turn" neck at 0.270. I'm using Lapua brass and loaded rounds neck measures 0.2685.
Most would consider this to be the minium clearance for neck dia.

Cheers
Leeroy

 

[Rflshootr]

gt40

The general rule of thumb is .002 larger then the neck diameter of a loaded cartridge.

 

[jackie schmidt]

Neck Clearance

.270 would be my dead minimum, and with some flat base bullets with a substantial gas ring, that might be a tad tight.

.271 would error on the safe side.........jackie

 

[fx77]

I have a BAT with Lapua no turn neck 6 BR and it is a .270 neck