300 AAC is too short to run Long Action. It’s the same length as 223 basically. You want the Oryx Chassis for Axis Short Action. And use these magazines for it. https://mdttac.com/223-mdt-metal-aics-magazine/


The Axis is made to be Short or Long Action by simply flipping the Front Baffle around. The Receiver itself is the same regardless. BTW, Welcome.