Originally Posted by Hookturnr
I agree that there are differences from one lot to another as well as from one brand to another.
This thread has been debating sorting your cases by volume OR sorting by weight.
My point is that if you weight sort your brass and eliminate the outliers, then you should be able to keep a very consistent load regardless of the volume meaasurement because all of the remaining cases will be expanded to a near identical volume during the pressure event. The only variable concerning the case during the pressure event would be the thickness of the base and web and if you already weight sorted then you should have minimized that variable.
I agree that case wall thickness does make a difference in volume but that variable should have already been nearly eliminated by staying with the same brand/lot of brass.
I shoot several different brands of brass in my rifles and have found some have drastically different volumes whereas others are nearly identical. My 300 RUM loads are approx. 1.5gr different between nosler and remington brass, however my 25-06 loads stay identical in both remington and hornady/frontier brass with identical accuracy and identical velocity averages. Thus my conclusion is that the base/web construction of both in 25-06 is nearly identical and my weight sorting has eliminated the cases with a thicker/thinnner base/web than the average of the lot.
Over all, I just don't see how you can derive any true value from volume measurements of the case when the volume is going to change to chamber dimensions the instant you pull the trigger.
You would THINK that would be true, but the difference in wall thickness, etc. can, and does, make a difference. It is true that you eliminate a lot of the difference by weighing the same lot out, but if you volume measure as J.E. described, you will STILL find some of the cases with different volumes.
ALSO: I noticed in my previous post that I said weighing to be "consistent" and what I meant to say was "inconsistent" Sorry about that.....Rich