Most states prohibit the use of full metal jacket ammo for hunting.
Most states prohibit the use of FMJ for hunting game. In Texas and numerous other states, hogs are not considered game. In Texas, they are considered exotic (non-natural) animals and may be taken by any legal means with no limitations on typical weaponry such as firearms so long as the firearms are legal.
In regard to the OP.223/5.56 is fine for hogs. You will get the folks that quote some African big game hunter who used to say, "bring enough gun." Your AR15 is enough gun as is the caliber, but your choice of locations to use the gun/caliber effectively are smaller than with bigger and more powerful calibers. Heck, you can use a Crossman pellet gun from Walmart if you can get to within 6" of the head and put a shot into the brain. It is enough gun for that type of shooting. So choose wisely.
A buddy of mine gave me a hard time about a hog that got away and did the whole "bring enough gun" chant. A few months later he put a 12 ga slug into the leg of ... ... ... ... the feeder just above the animal he was intending to shoot. As I ribbed him, he apparently did not bring enough gun to drop his quarry with a miss. There was a nice big dent and partial hole in the feeder leg, but even the feeder didn't go down.
So with a smaller caliber, you are going to have to choose your shots wisely. I like to make CNS shots. I have taken several with M855 green tips through the head. There, it is important to not just hit the head, but to do damage to the CNS.
I have seen vids on Youtube of AR15s in .223/5.56 being used at greater distances and not just for CNS shots. No doubt most folks don't post the vids of the animals that got away. Some are at what I would consider to be considerable distances. My preference is for less than 100 yards and really I don't feel completely comfortable with the shots until inside of 50, but they work great.
Bigger calibers give you a bit more room for error. Me personally, I hate to chase down a hog that doesn't drop on the spot. They are often dead within 100-200 yards, but they never run closer to the truck. They run into briar, poison ivy, ravines, and just places where it is harder to find them and harder to get them out and tracking a wounded hog that isn't dead can be dicey.
Choose your point of impact wisely given the caliber, velocity, distance, and the orientation of the pig relative to you and if you get it all right, you should have good success. This is tougher when you don't know what the POI is for the distance, so familiarity with the ballistic trajectory of your round is important.