hmmm. What is the most suitable caliber for wild boars? Personally, I would have to say anything large and hard hitting.

Of course, just about any bullet is capable of putting down a hog in one way or another. A 22lr shot between the ear and eye (not behind the ear) in the brain should drop any pig on the spot. But the 22lr is not adequate for shooting any sizable pig in the vertebrae or lungs nor will it give a blood trail. 223 or larger will break the vertebrae destroying nerves to the vital organs and thus killing the animal cleanly and efficiently. But such small caliber bullets are still not capable of giving a good reliable blood trail when you hit the animal in the lungs. 270 and 7mm about the minimum but serious boar hunters should go with something even larger. Smaller cartridges such as the 30carbine are capable of dropping the pig in their tracks by breaking bone and severing nerves in the neck region or by hitting the brain. But the 44 magnum is what I consider minimum for handgun cartridges. 357 also works but is not as good as the 44 mag or larger.

For serious hog hunting, you want something 30 caliber or larger. That way, you will put a large hole in the animal giving you a better chance for a good blood trail if the animal doesn't go down immediately.

A 30-30 is actually not a very powerful cartridge by today’s standards. Although many pigs are killed with it every day, I do not recommend it. There have been many horror stories of animals going a long ways after being hit in the vitals with a 30-30 shot(s).

Good long range rifle calibers are .300s, .308, and .30.06. 270 and 7mm or equivalent also work well at long ranges. All are capable of cleanly destroying the vital organs at long ranges out to 300 yards or more while giving a large enough hole for a good blood trail. All are easily capable of dropping the animal in their tracks when hitting the front shoulder, neck, and brain areas.

For shorter ranges especially in thick bush, the same cartridges mentioned above will all work fine but it might be in your interest to have heavier harder hitting bullets that can blast through sticks without being heavily deflected. Shotgun slugs are ideal. 44 magnum is also a good hard hitting choice. 444 marlin and 45-70 Govt. are also great bush cartridges and all are good out to 100 yards.

Shot placement is more important though because a 223 and 300 mag are all going to do the same thing to the animal when shot into the front shoulder/neck region. They both will break bone and severe nerves inside the spinal column and maybe even send bone fragments into the lungs causing further damage. One will make a larger hole. The larger will also give a better blood trail after a shot to the vitals. The larger also gives you the opportunity to take vital shots while the 223 should be limited to head and neck/front shoulder shots.