Re: 416 barett
Sounds like you haven't chosen your big bore yet. Not real sure why you want a 2.5x night sight on a LR rig either? So here's what I'm thinking. You obviously have the money to dump on something extreme. Both calibers require lathe turned bullets to develop the BC that is necessary for the calibers in question. In my search only the 300grn TTSX Barnes had a decent BC of .555. The Sierra 350SMK in .375 was only a limited run and virtually unavailable.
As you should know lathe turned bullets do NOT expand. Therefore hunting with these bullets are out of the question. So my suggestion is to pick one and kill a ton of stone walls and rocks (unless using the Barnes bullet). The 416 Barrett is a proven system that is killing bad guys all over the globe. As far as the 375 H&H, its a good caliber used to kill countless game in Africa for almost a century. You can only do better using the bigger calibers such as the 375 Ruger, 375 RUM, and Weatherby 378. The top of the pecking order would be the 375 Allen Magnum that will give you all the velocity you need to do what ever it is you are going to do with it.
The most practical caliber that you mentioned especially if you are going to use a Gen I 2.5x night sight is the 338 Win Mag. A nice load using a 225 SST or a 250grn Berger, Sierra, or Hornady BTHP at 2650fps will kill all you want at the distance you are going to be able to shoot with a 2.5x scope.
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