So you want a "weapon of war that has no purpose other then to kill people" OH wait I am not Schumer, Hitlery, Fienstein, Boxer or any of those other whack jobs.
Money is no option:
I think the best is a Springfield M1A Super Match or a H&K PSG1. I had a Super Match, great gun easy to shoot 600 yard shots with iron sights. I sold it a few years back for a bunch of money, over $1,000 more than I paid for it.
The M1A SOCOM is a good choice also, but magazines can be spendy, that goes fore any of the M1A's.
The best bang for the buck option.
There are choices, the PTR-91, FN FAL variants (go to GunPartsGuy.com or something like that he is in Vancouver he is a FAL guru), the lesser models of the M1A's.
either way you go you can be shooting a real gun, my cousin warned me about selling the Super Match, and said you will miss it at times. He was right, the little AR just does not do it. Myself I have been casually looking at FN FALs.
what ever you buy check on magazine cost, and what ever options you are going to add. Do the total cost of the gun thing, before you buy, with politics the way they are I would buy a minimum of 10 magazines, they may not be available later on.
steve