Pushing 70 years old and now living in the country on acreage with a house set back from the road, I figure it is time to acquire a rifle that can provide some good perimeter defense fire power out to about 300 yds in the event of a SHTF situation where pretty much anyone that plows through my gate is up to no good and would need to be quickly convinced to move on and find easier pickings. I am no longer the kind of rifle shot that I used to be so at this late stage I am looking for the right combination of accuracy, capacity and penetration power. Not a big fan of the 5.56 but I realize its advantages of light weight and accuracy over the 7.62 rifles I have used all my life. I have never owned an AR although I am familiar with them and have shot enough of my friends' to be comfortable with their capabilities for perimeter defense. My two main rifles in the past have been a Remington 742 in 30-06 and a Winchester 100 in .308. Both excellent and accurate rifles for me and the main reasons I never bought an AR. Neither, however, has the capacity or reliability I would want in something that my life or family depended upon to hold off a half dozen or perps intent on bodily harm. Given that I intend to buy a quality AR in 5.56, I am a bit at a loss about the following: 30 rd magazines seem to be the right compromise between capacity and weight. Are there better options if defending a well entrenched position? What kind of optics? I am used to using quality 3 X 9 variable scopes but it seems I might be better with a more rugged "point and shoot" optic that provides better sight picture instead of magnification. Night vision is fine for hog hunting but is there any rationale to have it on a defense rifle? Is a suppressor worth the paperwork and cost for this kind of rifle? Will it provide recoil advantages in a combat situation? I hope these questions don't sound stupid, but I have spent my life relying on handguns for home defense. Of course, living in the cities and suburbs is a different animal and I now realize the I am a bit out of my element in the country and want to have a plan to defend my property if need be. I feel perfectly safe where I am now but, then again, no place is really safe these days, especially when some folks view older citizens as easy targets. Part of me says having a rifle at the ready with several hundred rounds loaded is foolishness, but the other part tells me it is no more foolish than when I lived in the city and had several pistols stashed in different rooms of the house so I would never be caught off guard.