The calibers I have shot them with most;
.308
45/70
.375 WSM
The .375 WSM is my favourite to date. Great hitting power like the 45/70 but improved trajectory.
I’ve killed hundreds of feral hogs almost exclusively by spot and stalk and jump shooting. With the occasional stand hunt or “drive by” opportunity. For that style of hunting a .358 bore or .375 bore rifle with iron sights or a low power variable scope is a really good choice.
I’m not saying anything else mentioned in this thread won’t work. What I am saying is that on hogs, and especially big hogs that are probably not giving you the best shot presentation a .358 or .375 gives you a substantial penetration and knock down advantage.
I’ve also killed a number of hogs with heavy rifles such as the .458 Lott and .470 NE and .416 etc etc. not because you need that kind of horse power, I used those rifles on hogs because there simply isn’t any better practice available when getting ready for Africa and DG hunting. Hog hunting the way I like to do it is the best DG hunting simulator you can possibly have.
My .308, .30-06, .270 etc etc have accounted for numerous hogs with no issues. They are perfectly adequate for hog hunting.
I will tell you this though, I was shocked the first time I recovered a .375 H&H, 270gr X bullet on the offside hide of a gnarly old boar after a fairly close range broadside shot. I figured it was a fluke. About the tenth one I found in similar situations made me realize that on a big compact boar with a well developed cartilage “shield”, it doesn’t take all that much to punch through it into the vitals. But they are a bullet stopping critter when it comes to an exit wound.
When you step up to a medium (.40 or bigger) or a heavy I’ve never seen any hog stop the bullet. But they will definitely stop 270 or 300 Gr .375 on occasion.
I’d love to see a slow motion video of the off side hide when it does stop a bullet. I’ll bet the hide stretches out a foot or so before it snaps back. The hide on a big boar that’s well developed is just the right mixture of thickness and elasticity to be a great expanded bullet catcher.