I shoot a .223 for hogs.  I have a remington 700, I have found that the federal rounds shoot well.  The best round is the federal 69 grain hollow points.  Blackhills ammo also shoots good.  The only thing with shooting the hotter rounds is that your barrel needs a better twist ratio.  Once the hotter rounds leave the barrel they with drift off target with a regular 9 to 1 twist.  Try the federal 55 grain blastic tips for your basic .223 gun.

What Randell says is right, but even with that every gun seems to have its preferences.  I'd try several different rounds and see which one groups best.

We have come out with a new line of products called AR Hunter. Check them out www.teashuntco.com I picked up a bunch of New dealers at the shot show in Orlando last weekend.

Link did not work.  My twist 1 - 8.  How about 69 gr Federal Sierra Matchking bthp?

1-8 will work decent at 100 yards (less than half an inch most likely depends on the gun), but once you start getting out any further good look.  Where they go who knows!