I've been reloading .300 Win. Mag for a few months now and had finally experienced case expansion problems after several fireings on some of the brass.
In tyring to find a solution to save and reuse otherwise still reloadable brass I found this web site called Innovative Technologies Innovative Technologies - Reloading Equipment
They make a Belted Magnum Collet Resizing Die that works on most all reloaders. So I just ordered their resizing die and also their Digital headspace guage.
Looks like good stuff and the price was right and it should get me more reloads out of my brass.