300 Winchester Magnum dummies?

Given the general use of inert ammunition for weapons handling training, is the 300 Win Magnum cartridge made as a dummy round? If yes, are these military contract and what headstamp markings are they found with?

Happy collecting, Peter

For what it is worth, I have loaded rounds in my collection with the military style headstamps of:

FC 93 (over) 300 WIN MAG

WCC 93 (over) 300 WIN MAG

I also have a number of dummies with commerical headstamps in this caliber/case type. (R-P with both long and short dashes, WW SUPER, SUPER-X, SUPER SPEED, DOMINION, and DWM (code- K DWM W).

As dummies are needed for various uses I’d think it likely commerical dummies would be used as they could be easily procured.

Thoughts only - not to be taken with other than a single, grain of salt.