Lee 7mm stw and 7mm ultra magnum factory crimp die crimps the bullet in place more firmly than any other tool.Tests demonstrate that even bullets which have no crimp groove will shoot more accurately.A firm crimp improves accuracy because pressure must build to a higher level before the bullet begins to move.This higher start pressure insures a more uniform pressure curve and less velocity variation.Type: Factory Crimp Rifle DieCaliber: 7mm RUMDie Type: CrimpDie Series: Factory CrimpIn Set: 1