Chamber "size" v.s. case life

[Eric B.]

When I had my HS Precision rifle built in '98 I tols them to ream the chamber to "absolute minimum SAAMI specs.", which they did. I wanted as little brass movement as possible (longer case life) and as much bullet alignment with the bore as possible while still being able to shoot factory match ammo if I wanted.

A few years later I noticed HS Precision advertising that spec in those very words. Maybe my request was just one of many like it.

 

[JRM83]

Correct me if I am wrong, but doesn't chamber size only affect the brass on the first firing if your dies are set up correctly? It shouldn't matter if my chamber is .006 over saami min or .001 under, if I bump the shoulder back .002 each firing it is going to result in the same amount of stretching on the brass in either chamber. The first firing on the big chamber is going to result in more stretching, but each subsequent firing will be the same as the smaller chamber. I would imagine the neck would split or the primer pockets go before case head separation caused by resizing would be an issue. Does the tighter chamber effect the neck or primer pocket in some way?

 

[Clark]

My .223 reamer has a .250 neck.
My 6mmBR reamer has a .272" neck.

My .223 FL die has been honed out to .246".
My 6mmBR FL die has been honed out .265".

What does it all mean?
SAAMI chamber specs are too sloppy.
Factory dies are too tight.