I am going on my first South African safari in 2015 and do not know what is a good caliber for baboon up to Impala. I am in gunsmithing school and am building a 375 H&H. Of course I will shoot it many times over and over before going to make sure it is 100% reliable. I know this will handle any of the bigger game I want to hunt but assume (we all know what that does) it is way to big for a baboon and monkey and some of the smaller cats I am wanting to hunt. So any thoughts on a smaller caliber? I was thinking maybe a 300H&H so I could have a matched pair. Place I am going with says .270 is their smallest caliber allowed. I do not have a good gun above .260. Any thoughts would be greatly appreciated.
Hello Parsons, and welcome to the board!
I did my first Safari in 2012 and will be headed back out on my second safari in 6 weeks. Good times abound!
Just getting calibers out of the way: 300 H&H = 300 WinMag. Give or take 50 fps pending bullet weight two are virtually ballistic cousins with a few decades separating them. In my Pre-64 Winchester my 300 H&H with a 26" barrel gave 2,950fps with a 180gr. TSX. I used it on Steenbok to Kudu.
The 275 Rigby = 7x57 = 7mm-08 (*sorta). The 7x57 tends to work better with longer bullets but that's debatable. In my Ruger #1 the 7x57 delivers 2,850 fps with 145 gr. Speer HotCor's and 2,550 with 175 Hornady IL Round Nose bullets. Both loads in my rifle are 3/4" performers. Historically the 7x57 has been one of the great unsung heroes. It's taken everything in Africa including and up to Elephant with the right loads.
So, I used my 300 H&H on my first safari. My second safari I'm using a 7mm Rem Mag and my wife is using a 7x57r. Any of these rifles will work just fine on virtually any Plainsgame critters. The real question is what your load looks like. The mono-metal bullets (TSX, E-Tip, GMX) penetrate incredibly well and don't do as much cape damage relative to the traditional fast expanding cup & core bullets. So if you want to hunt small critters I'd recommend sticking to the Mono-Metals.
Given that you have a .260 already, stepping up to a .300 makes a lot of sense. The .300 also gives you a bit more margin for error over a 270 with a bigger bullet and better penetration. That's arguable. All other things held equal, a .300 does offer a bit more killing power than a .270.
About the only thing I can add on the .300 H&H is this: I only got about 6 reloads out of the big 300 case before they started showing signs of distress and I started seeing case head separation. That long case just doesn't handle stretching as well as the new .300 WMag case does. Accuracy of the H&H is superb, my 60 year old rifle still delivers 1.5" groups at 200 yards.
I also have a .375 H&H that I've used on deer. If you're concerned about small game with that rifle, don't be. A lot of those bullets are designed to expand on thicker skinned game. For instance, the Texas Whitetail I shot with a 300 gr. Partition did not expand...but that deer was dead so fast I thought I'd missed! (*he vanished into the tall grass where he was feeding, dead without ever taking a step). The exit hole was .375...not that it mattered.
The real question isn't "which cartridge is best". Any of them will work on Plainsgame. The real question is "what gets you excited". If it's a .300 H&H to have the matched, classic pair, then do it. I did and I have no regrets. It's a wonderful, classic old gal that still has the legs to run with the best of them today.