It is the 338-300 RUM that goes by about a hundred different names depending on what shop it comes out of. I developed my 338-300 RUM version in 1998 and there were many that followed. I like to keep the name simple following typical nomenclature so everybody easily knows what a guy is talking about when he mentions it. Sure helps keep down the confusion. It died down in 2001 when remington introduced the factory 338 RUM which is a better cartridge that fits better on the rem 700 action. Performance wise they are the same thing. Remington shortenned it a little making it the better fit on a factory action with long, heavy, high bc 338 bullets. Plus you can buy everything cheaply over the counter like dies and brass.