Haven't seen any stock/factory rifles in 338 NM, but we make only custom.
We stocked up a few years ago with 338LM Brass, Berger 300 OTMs and had custom JGS 338LMAI Reamer. Have several Krieger 1:9.3 barrels 32" & 33", a Bat Action Single shot dual port, and several McMillan XIT stocks.
This past year was second guessing and thinking about going with a 338NM.
Can't really go wrong with either the Lapua Mag or Norm Mag.
If you are looking for a ELR cartridge these are two of the BEST!
Think that maybe there is more components available for the 338LM at this time.