“The heart of the rifle is Nosler’s new Model 21 action, designed in collaboration with Mack Brothers, the reputable South Dakota sibling duo with a growing reputation for building some of the finest rifle actions in the industry. Most notably, their popular EVO action has built an impressive following among serious precision shooters since its introduction in 2018. The newly designed Model 21 blends the best features of the EVO with unique Nosler-engineered customizations, delivering a solid foundation for peak performance right out of the box.”
From nosler
https://www.nosler.com/model-21-rifles.html