How about a little liability?? With the court systems the way they seem today, common sense has disappeared. Years ago, a reloader was one who was, for the most part, knowledgeable to the fact that this was a relatively new area, and experimentation was pretty much up to the individual. Guidelines were given, but that's all they were. If you blew your gun up, lost an eye, or worse, it was pretty much of your own doing. Period. Today, if something is put in print, it seems to be absolute gospel, according to the current court system. Common sense and a little bit of previous knowledge weigh nothing anymore. Here it is----in black and white...safe loads....
For what it's worth, that's my part of it, although I do see a lot of merit in other reasons, also. Thanks...Emmett.