No expert in what brand of barrels to use, but just to be here to correct that you will need 310mm, not 300mm barrels to fit into that outer barrel.
Also a NEMO clone is better (as long as the quality is decent) than a normie cylinder. Not wrong in more of dem air.
Also a NEMO clone is better (as long as the quality is decent) than a normie cylinder. Not wrong in more of dem air.