Distinctions should be made between precision rifle, often single stage and very precise powder measuring of each round, versus a progressive, which makes some compromises in favor of automation. The tolerance +_ some fraction of a grain or percentage for high quantities like your 42g, needs to be realistic. Otherwise, being obsessive as one might be with precision rifle is going to cost you far more than a simple Lee unit.
My Lee case-activated Auto-Disk Powder Measure has been dropping consistently 7.0g of SR4756 all afternoon, as I use that powder load on 4 different bullets in .357 magnum. The powder measure carries the Adjustable Charge Bar, which would not be applicable with disks or large caliber rifle charges.
All these slide-aperture-based devices vary in consistency based upon the type of powder, each of which may need to have its own consistency expectation. It may not be the equipment or the price of the equipment that makes the difference.
Last edited by Real Gun; September 29, 2013 at 04:48 PM.