The 218 Mashburn Bee is an improved version of the factory 218 Bee. The cartridge was the work of A. E. Mashburn of the Mashburn Arms Company in Oklahoma City, Oklahoma. As near as can be determined, the cartridge originated in about 1940 or thereabouts. The improved case produced better ballistics than the original Bee and also offered longer case life when reloaded. There are other Improved versions of the 218 Bee, but they are all pretty much alike. The Mashburn Bee will deliver about the same velocity with the 55 grain bullet as the factory Bee delivers with the 45 grain bullet. The Mashburn Bee was fairly popular until the advent of the 222 Remington. It was, and still is, a very accurate varmint cartridge. The best powders for loading these small cartridges are IMR-4198 and IMR-4227. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.