If I was going to get a rifle that shoots a NATO round it would be a Ruger Mini 14. Ruger Mini-14 Autoloading Rifles
have a rem 11oo just looking for a good starter bug out l love the sense hf humorI have a REALLY nice wrist-rocket...but it comes with almost 5,000 rocks...
Seriously, did you have something in mind already? I have several rifles I might consider letting go of and save you some cash to boot...
You might want to go look at Rossi's Model 92, my wife got me one for fathers day in 45colt that I have offically fallen in love with, and they make a 16in barrel model that I wish I would have seen before she got this one. Local the Rossi NEW is running about $400-450 with tax.
If home defense is your only concern, why not look at a shotgun?
Get a pistol grip shotty. An 870 or mossy 500 get it done on a budget. ALL LEOs will tell you a shot gun with buckshot is best for HD. You won't get much of a rifle for that kind of cash unless you want a WASR AK. Even at that, experienced gun owners will tell you to save up and get an AR instead.
There is something espcially scary about looking down the barrel of a shotgun...at night...with a pissed off home owner on the other end...
I've never experienced that myself...probably because I don't invade other folks' homes...