Lee Precision Micrometer Full Length Die Set Features The Lee Precision Micrometer Full Length Die Set is engineered around the .280 AI cartridge and its .277 inch bullet diameter giving reloaders a dedicated two die set rather than a generic multi caliber kit. The full length sizing die resizes fired brass back to proper dimensions for reliable chambering which is especially important with an Ackley Improved case that has been fire formed and needs consistent treatment on every reload. The seating die carries Lee s micrometer adjustment feature letting the shooter set and record a precise seating depth and return to it shot after shot. That repeatability is the difference between a load that merely chambers and one that groups well downrange. This set is intended for handloaders who have already invested in a .280 AI rifle and want ammunition tailored exactly to that chamber. Because the dies are matched to the .277 inch diameter standard for this cartridge there is no ambiguity about bullet fit during setup. Lee Precision built its reputation on affordable accurate reloading tools and this two die set continues that approach for a less common but increasingly popular Ackley Improved chambering. A reloader working up loads for hunting or long range shooting will appreciate the fine control the micrometer seating die provides over every round produced. Lee Precision Micrometer Full Length Die Set Specifications Manufacturer: Lee Precision Caliber: .280 AI Bullet Diameter: .277 Die Type: 2-Die Set Full Length Available At: GrabAGun