12-31-2011, 11:09 PM
We made a mistake in our (AA) published figure for the case length. The chamber will easily absorb cases until they split but as most reloaders want a trim length I went with a figure that should not be exceeded and then a tolerance. ie once the case gets beyond 1.526 it should be trimmed back to between 1.526 -0.006. This is a reasonable tolerance for any small hand tool and a pair of cheap calipers.
In the absence of a temperature controlled inspection facility and laboratory type CM to measure the lengths I still find some quandry in asking someone to trim a piece of brass to an exact length +/-.000x nor should it be necessary. I frequently wonder during discussions such as these how a small mass produced hand tool can acheive a repeatable tolerance that exceeds a multi thousand $ CNC machine but that is my cynical nature.
Factory new brass is well short of the chamber transition and brass will rarely grow such that it demands to be trimmed. Hornady and Western both work from the case print so if in doubt use thier figure.
As we print updates to our load data we will correct our trim figures.
In the absence of a temperature controlled inspection facility and laboratory type CM to measure the lengths I still find some quandry in asking someone to trim a piece of brass to an exact length +/-.000x nor should it be necessary. I frequently wonder during discussions such as these how a small mass produced hand tool can acheive a repeatable tolerance that exceeds a multi thousand $ CNC machine but that is my cynical nature.
Factory new brass is well short of the chamber transition and brass will rarely grow such that it demands to be trimmed. Hornady and Western both work from the case print so if in doubt use thier figure.
As we print updates to our load data we will correct our trim figures.