So the 100 acres is primarily open land? 85% open pasture.
While medium calibers like 6.5 Grendel/6.8 SPC are great for typical hunting distances (less than 200 yards), I would suggest going with something more substantial for 300-400 yards if that is going to be your typical hunting, something like 6.5 Creedmore or .308. At 300-400 yards, you are probably going to be doing more sniping than fast and furious eradication hunting that folks do more up close (inside 100/75/50 yards), so you could probably do just as well with a bolt gun as a semi. Pick a good hunting bullet. A favorite here is Hornady SST, but there are a lot of good choices out there. Stay away from FMJ and super amazing miracle ammo and stick with tried and true stuff.
Luring hogs? Plain old corn works well. Get a feeder and have it only spit corn when you plan to hunt. I have my feeders running only in the evening. That keeps other animals from devouring much corn during the day when I am not there to hunt. You can try all the concoctions/variants of corn such as soured corn, jello corn, beer corn, Big Red corn, Kool-Aid corn, honey corn, etc. and no doubt the hogs will eat the stuff, but I have never been able to see where it actually produces any sort of better results given the extra time and expense. Some people swear by such mixes, but I can't tell where they actually get more hogs or get them any quicker.
You can also try a Pig Pipe or Pig Barrel that will slowly dole out corn when pushed around by hogs. It will help keep hogs in place longer, but also works well in combination with a feeder.
Optics....at 300-400 yards you are probably going to want something with some good magnification. The question then is whether you want Night Vision or Thermal. If you go with night vision, you are likely going to want a good IR illuminator, such as an IR laser to help light up the target area on particularly dark nights (which are great nights for hunting).
So what is your budget?[/QUOTE] Sounds like I may be needing two different guns....better focus on this hog problem first. As far as a budget....don't have a number in mind but I will buy whatever I need to get the job done as effectively and efficiently as needed. I doubt it will come close to my annual shotshell cost...haha.