It must be a specialty hunting bullet.
The name of the forum is Long Range Hunting.
The general problem with the 25 cals is that the bigger bullet companies do not make any long range hunting bullets in 25 cal so everybody just makes do with poor choices of medium range bullets.
From Left to Right
257Wby with 130 gr RBBT HP Wildcat
7mm 200 gr RBBT HP Wildcat
257 cal 142 gr RBBT HP Wildcat
257 cal 130 gr RBBT HP Wildcat
6mm 115 gr Berger (IIRC)