The only trouble you are going to have is shooting an old big boar behind the shoulder. The males will fight and develop scar tissue behind the shoulder where they have been slashed which acts like a armor plate of sorts. That scar tissue will stop a smaller load at times or certainly affect penetration. You won't see this very often but it does occur. Other than that, a .243 will kill the hell out of a pig if you hit him right.

I've killed a handful of them with a 6.5 Grendel and the .243 is faster than the Grendel, and typically delivers more energy downrange.

If you relegate the 243 Win to be a 150 yard gun on big game from Hogs to Moose, there is nothing it won’t kill.

No damn armor plated boar can withstand a 243 hit under 150 yards.

I probably kill 30-100 pigs per week with various calibers and types of guns.

When I was having a little trouble with pigs at the house I was shooting them in the shoulder with a 223 and they never took a step. The biggest was only around 150 pounds but the 243 should be more than enough for any pig

243 will lay em out.

Usr Barnes Tripple shpck or Nosler Partitions on those shoulder shots. Makes a 243 come alive on body shots. In the noggin, well as everybody has already stated, just slip one in his ear.

About 1-2” below and behind the ear with about any caliber and he’s dead. Killed hundreds behind the ear with a .223.

.22 LR works too. I dont know how many I've killed with my .22 squirrel hunting outside of deer season. Gotta get a little closer with the .22 LR than with a .223, but right behind the ear is a dead pig every trigger pull. Now with a 556 or 223, I'll head, lung and body shoot them all day and it kills them dead as a hammer with any decent expanding/mushrooming ammo.

Dang big hog

We used to kill a bunch on Corp of engineer land on the river with a 22lr. Tha big hog I killed this year was 250+ lbs and I shot him on the ass and the bullet almost exited his chest with a 308. Hogs aren't as tough as people make them out to be

^^^^This^^^^