Thread: 7mm Rem Mag sizing problems

Here is a suggestion, depending on when a chamber is formed, the first one off the line will have a chamber diameter of .006" more then the one off the line just before new tooling is installed. This is the SAAMI tolerance of major to minor size. Now sizing dies are designed to take brass down to minimum size so it will fit in all chambers. So major chamber size and minor die size creates alot of working of the brass.