AR optics….fixed vs. variable?

[shortround13]

ok hopefully last question. I think I figured out what has been nagging at me. On my stock M&P, 14.5" (w/ pinned muzzle device) 1:9 twist barrel and regular PMC ammo, with both irons and my eotech (unmagnified) I could keep all shots in the black at 200 yards…which seems fairly respectable. With the higher end components that I am building this AR with…what kind of potential range/accuracy should I expect? Is 1-2 MOA out to 5-600 yards reasonable? If so would an ACOG then be the limiting factor and would I be better served with a more precise optic? Or would they both work and it just boils down to preference?

[ExtremeX]

[shortround13]

If you want to start playing with 223 at distance it really helps to start using heavier match bullets with higher BC values if you want to maintain 1-2 MOA type accuracy at those distances.

[lavey29]

I have a similar dilemma and got some good input in my thread to if you wanna reference it:

http://www.calguns.net/calgunforum/showthread.php?t=825292

[Droppin Deuces]

that's what I kinda thought about the ACOG. Its more a minute of person accuracy no? Well…I have been keeping all my brass to eventually start reloading..but for a while I will have to bite the proverbial (literal??) bullet and buy some good 70+grain ammo….

It's not the accuracy of the optic. It's the reticle which is your limiting factor with an ACOG. Like ExtremeX said, the reticle is going to be calibrated for a specific weight and velocity being fired through a specific length of barrel.
That's not to say you can't relatively easily work up a round with just about any bullet to match your reticle reasonably well.

I find that the secret to being accurate with an ACOG is to zero it as far out as you can see. I zero mine at 25 then fine tune it at 300. From there it jives pretty well all the way through the rest of the hashes as long as my ammo has enough muzzle velocity. I don't care if it hits an inch or two high at 100 with 75-77gr loads. If the target is that close and i need to hit it with any kind of speed, I'll just use the RDS on top anyway. It's way faster than using a magnification ring on a variable. That's my experience, anyway.
At any rate, if I were going to shoot anything other than M855/ss109 using an ACOG, I'd probably keep it to 68-69 grain max since you can load it pretty hot and still keep it as flat as a 62.
Also, do yourself a favor and get the crosshair reticle if you pick up an ACOG.

And yes, 600+ yard shots are a snap if your ammo is up to the task, although, with 4x magnification, I don't expect any better than minute of man at that range. If you want MOA accuracy that far out, get at least 9 to 10x on the high end.
I have a Vortex PST 2.5-10x32 on my 18" upper and it is an MOA shooter all day at 675 with Hornady 75 HPBT.

[shortround13]

aaahhhhh decisions decisions….. I like the kind of no nonsense frills of "hey I can hit this, easily, and fast" of an ACOG… but I kind of want something that is more accurate….without branching into the high magnification scopes. I think I am leaning towards the 1-6 ish types…with US Optics and SWFA on the top of my list. I realize the 6x won't give me the extreme accuracy as a higher power, but…it should be more than a 4x ACOG….