I have shot two moose with a Sako 85 Blackbear in 9.3x62 one moose with a Ruger Alaskan in 375 Ruger and 1 moose with a Ruger # 1 in 375H &H. They all died.

They are both Great caliburs and my thoughts are that the 375 H&H is a 9.3x62 only at 100 yards further out. If you can do it at 200 yards with a 9.3x62 then you can do it at 300yards with a 375 H&H.