I think quite highly of the .300 Win Mag as a long range precision rifle cartridge. That is what my Spud Gun is chambered in. I have been very, very pleased with the results I get with it. I also find it interesting the link Ry supplied to the development history reports the Federal Match primers are used in the new ammo–which is what I use when reloading for my Spud Gun. They are using a 220 grain Sierra Match King bullet however. They considered and rejected the 210 grain VLD bullet which is what I use for reloading. The moly coated 190 grain Sierra Match King is used in the Black Hills match ammo I sometimes buy which also works very well for me. I prefer the 210 VLD over the 190 SMK because I get a little less wind drift and I should be good for 1500 yard shots versus 1300 yards for the 190 SMK (at sea level, 59F).
I’m glad I have enough ammo to last me until (I hope) the Army contracts are fulfilled.