One Cartridge not a Box: 6mm Dasher (Wildcat), custom loaded using new Peterson Brass cases with “PETERSON 6mm DASHER” Head-Stamp and loaded with a Berger VCD Target, 115 grain, 6mm elongated projectile.

History of the 6mm Dasher cartridges:
The 6mm Dasher originated was a wildcat cartridge  back in the late 1990s as a shortened  neck version of the 6mm BR-Ackley wildcat, which itself  was based off the 6mm BR Norma.
Brass is available from a few producers.
It is used with a elongated heavy 6mm projectile and used by many professional competition shooters.
I does not seem to be in SAAMI Standards as of this writing. 11/03/2021