375 H&H will do it. I know I just did it 2 weeks ago. He dropped like a car had been dropped from a crane.
This is a loaded question because at what distance are we talking? I've killed 2 buffaloes, the one I shot last week was 44 inches. In 2021 I shot that buffalo in the neck at 40 yards. It knocked him down, he ran 25 yards fell & I used a follow up shot.
2 weeks ago we tracked a buffalo up a still hill on a game trail through a thicket in Zambia. We thought he was well ahead of us after we got off the truck. He wasn't! He was a lone big old buffalo by himself. He didn't go far after disappearing in the bush. He was sitting facing forward towards us after about tracking 300 yards in. He was sitting atop a slope alone. Stepping on the dry leaves my ph was trying to find him, the tracker was frantic telling us he's right there he's right there! I couldn't see him the PH couldn't see him. The tracker is going crazy poiting. Then this huge black mass moved & I could see through the tall grass & brush he stood up and looked at everyone. I mean he looked pissed. My PH whispered to me, you have to make this shot, it has to be in the head. Can you make this shot? I whispered back, yes I have to. He said yes because he's going to charge any second if you shoot him front on. I couldn't anyway because the grass and brush were that high. I could just see his horns eyes & face, barely the neck. I put the rifle on the shooting sticks. My scope was already turned down to 2.5 power. I put the cross hairs right between the eyes just below the horns. As I did that I heard a loud snort. My PH said again you've got to make this shot are you steady. I didn't say anything I just squeezed off, boom. He fell like 2 tons of bricks. I expressed to my PH, "nobody is going to believe this". He said, "I wouldn't have believed it if I wasn't here."
My 2 buffaloes were shot with the same gun 375 H&H Swift 300 grain Aframes. One in the neck the other directly between the eyes. Both killed I would say fairly easily.
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