In my experience FALs are a 1.5-2.5 moa gun with iron sights. I like one with a T1 if i am looking for vehicle penetration or more impact down range then 5.56 or 7.62x39.
I tried Armalite AR10s and was not impressed with durability. I think a proper AR10 type is hard to beat for accuracy but I am not up on the past 5 years of developments.
If I go down this road, I will probably go SCAR 7.62x51 as a battle/designated marksman rifle with a T1 and or 1-6x scope. It is about 1.5-2.0 lbs lighter than a FAL etc... my buddies tell me it is 1 moa with match ammo.
I would like 1 rifle that covers most of what I can do with a FAL and with an AIAW .308. Trade offs are weight/ accuracy/ handiness / durability etc....
I have not done any 500yd work in some years so I am out of the loop.
This FAL has been my main .308 for the last twelve years: an Stg58 from DSA
At the time it was the best bang for the buck in FAL's, now I'm not so sure as their QC has become questionable. The best description I've heard of the FAL is it's a battle axe not a dental pick. Keeping that in mind I think it fills the role pretty well. However, if I was in the market for another .308 today, I think I'd take a hard look at the SCAR17 and the Colt 901.
If you're not looking to do better than 4 MOA, why not just stick with the 5.56? With a 4 MOA gun at 500 yards, unless you can shoot with zero human error, you'll most likely be scaring them instead of hitting them. A 5.56 can do that as well, while being lighter, handier, cheaper and having much lower recoil.
If you're still set on the 308, I would go for a sear packed MM21 on a tripod. F'it. If you're not a marksman, a rifleman is the wrong solution for 500 yards.* Combined arms, baby.
Okay, it's a 23, not a 21, but you get the idea.
* The US Army conducted a pilot-program DMR school a few years back, and found troops performed better all around with a standard M4 instead of accurized 308 weapons. Something to note.
"Are you ready? Okay. Let's roll."- Last words of Todd Beamer
I shoot just fine actually.
I'm not willing to sacrifice reliability for accuracy which seems to be the norm for .308 "battle" rifles.
I don't need <1moa at the expense of reliability under southwest desert conditions.
I need a rifle that will shoot to a 2-4moa unmagnified red dot while covered in dust from bouncing around in a UTV all day.
I do want something that will punch through '70's GMC sheetmetal out to 500 yards and still damage the person hiding behind that sheetmetal and 5.56 won't do that.
"For a moment he felt good about this. A moment or two later he felt bad about feeling good about it. Then he felt good about feeling bad about feeling good about it and, satisfied, drove on into the night."
-- Hitchhiker's Guide to the Galaxy --
Of what I've used a lot FAL Para and I understand the trade offs. But I have not much experience with recent items.
Bear in mind I am very used to them and have parts etc... In 1984 they replaced my HK91s because I like the ergos better.
If I shoot in enough on SCAR 17 I may go that way but I currently lack that experience.
I am still pouty today, after the Larue developments.
My SCAR H twins are set up with NF 1-4 scopes, with a T1 zeroed and available for each as an alternate sighting system. Not sure about 500, but I have shot them at 400 yards with good results with the 1-4.
PS: I have heard some good reports on the M&P .308, and if this is a "truck" gun, I would feel better about leaving it unattended than a H or equivalent.
Likes pretty much everything in every caliber.