You can still find the precursor from time to time - the ZKK-602 action, and Brownells used to carry the Korean clone, the BKK-602.
Here is a tip: you can save a lot of money on ammo and components if you will chamber in 338 Edge, which is the 300 RUM necked up to 338. It actually is slightly faster than the Lapua. It also has the same rim diameter as the 300 Win Mag, so you save on gunsmithing as well.