If you enlarge that photo you can see very faintly 320 Max which was I believe an early loading for the 400/375. The 320 grain bullet was also used early on with the 375 NE 2.5" The MS can however only feed rimless rounds. I believe this one is a 400/375. I have not seen any H&H catalogue pages that show a 375 NE 2.25" on offer, only the 400/375 Belted Nitro Express.

Guns International are still listing that rifle at $4599.

Waidmannsheil.