I have a few friends that use .223 in AR configuration and they all load up 62gr (I think) Barnes TSX bullets. Most use head and neck shots but I've seen them work "okay" on a heart lung shot though I wouldn't recommend that shot placement on the larger boars. With better bullet technology the little .223 can do some serious damage at moderate ranges out to 200 yards.
I personally use a 6.8spc, .458 SOCOM, .338FED, and 7mm.08 all in AR platforms. Though I still on occasion break out one of my lever guns when I am feeling ornery which consist of .30-30 and .444MAR or if I am REALLY feeling my oats I just take a matched pair of old Colt .45's.
It's really all about shot placement and knowing your cartridges limitations when it comes to hogs. If you are using an anemic round such as the .223, then you need to limit your shot options in both range and placement when it comes to the big boys over 150 pounds. That cartilage shield isn't bullet proof but it does absorb a hell of a lot of energy.