Most of my dies are RCBS.....and a few Redding....and only one set of Hornady.....

As far as I know all the makers use 12L14 steel and case harden the sizing dies.....and while some manufacturers may still be using reamers, many are now actually boring the finish cut in bar feeding CNC machines. Tolerances can easily be held very close that way. I'm staying with RCBS not because their dies are better.....their customer service is superb and there's a lot to that!