Folks, I would like some assistance. I'm certain this has been covered some where, at some point in this wonderful, informative, and yes, entertaining site, but I can not seem to locate the answer to this question: how would you go about SAFELY working up load without any published data? I'm wanting to load the Hornady 285gr BTHP for the 338Lapua Magnum in my 338-378 Weatherby, but I have not found a listing for this application. I think Hodgdon listed a 265gr and 275gr bullet, for the Weatherby, but not the 285. I'm having a difficult time with this; the two cartridges use the same diameter slug, and I'm pretty sure that the bullets don't care which name is used on them. Where do I start? Thinking at the upper end for a given powder of the bullet closest in weight. Am I on track here, or all wrong? I would appreciate some insight from more experienced loaders here.