chamber diameter of 6mm br

[dbaird]

What diameter should I have the chamber reamed, for use with a no neck turn 6mm br with Lapua brass???

 

[fdshuster]

dennis: I had my reamers ground to .272" neck diameter when I was able to use the gold, cardboard box Lapua. Now, with the plastic blue box, I've had the reamers reground to .269". My loaded round neck diameters are averaging .2665" to .267", no turn.

 

[bricktop]

I had the reamer made to 0.269" in hopes of being able to clean up the neck and have 0.002" clearance, but maybe I made it too large? I guess there is no harm in doing a 0.0005" clean-up and running 0.003" clearance?

 

[areaone]

Dave Kiff recomends a 2704 neck for Blue Box, whic is what you will most likely encounter on new brass. I have that reamer with a .60 freebore and it works great for my purposes, loaded rounds are 2.675-2.68 and have no problem, I do not want to turn necks. hope this helps.

 

[fdshuster]

We're splitting hairs here, I think. It's just not that critical. If it involved a chamber diameter .004" larger than loaded round, then, yes, I'd be concerned. Anything less does not matter.

I'd not hesitate to use .270", .269" or even .268" with the blue box. IMO.

 

[jonbearman]

Area1 ,I hope you meant .060 freebore.LOL What bullets is the OP going to use? That would make freebore slightly different.