Scout scope on an AR15? Why not?

Leupold Scout Scope

Doing this is something I’ve talked about before, and I have a couple of friends who have kicked the idea around as well. Why not mount a scout scope on an AR15 pattern rifle? Luckily, I happened to have a Leupold mount sitting around, and a Leupold FX-II Scout so I naturally paired them on my Troy Defense rifle. So why put a scout scope on an AR?

The idea behind the scout rifle concept and the scopes it created was to have a lightweight, fast handling rifle capable of delivering accurate fire out to intermediate ranges. The true “scout” rifles are bolt guns in .308 usually, although I think that the advances in .223 ballistics move the 5.56/.223 Remington in to the category as well. To follow the path of the scout gun, I wanted the end result to be an AR that held as closely to the ideal as possible.

The starting platform is my Troy Defense Lamb carbine, an 18 inch AR that would work very well as a DMR gun, yet manages to weigh under 7 pounds loaded. Once the scout scope was mounted, it was off to the range for zero and testing. Once the gun was zeroed, I wanted to see what advantages/disadvantages the platform had. The first major issue I run into is obviously the amount of eye relief required to mount the scope. You’ll notice that it bridges the receiver and the rail, which some people will tell you is a bad, bad thing. The reason this can be a bad thing is if there’s movement in your rail system, or if the rail and the receiver aren’t lined up correctly. On a quality carbine like the Troy, that’s not likely to be an issue. Sustained rapid fire showed no shift in zero.

Troy defense Lamb carbine with Leupold scout scope

The range did reveal a huge advantage to using the long-eye relief platform. With the scout scope equipped, it was easy to engage short and intermediate range high percentage targets with boy eyes open, much like how you’d use a magnified ACOG. The aiming eye naturally focuses down the scope on the target, and the non-dominant eye remains open to provide peripheral vision and to reduce eye strain. As someone who struggles with eye strain issues from closing one eye, I found this to be a tremendously pleasant feature to the scout-AR.

In close range engagements, you don’t really give up a lot of speed over a red dot; because the scope is relatively low power, you don’t spend a significant amount of time “hunting” for the target in the reticle when you bring it up to your eye. However, it does have a more narrow field of view than a purpose built AR scope like this Bushnell AR Optics 1-4x.

The short verdict is that this is a perfectly reasonable set-up for an AR, and to be honest I do like the Scout-AR. The Leupold scope is excellent, however the set-up doesn’t offer significant advantages over a good 1-4x variable from Leupold, Burris, or Bushnell. If you happen to have a scout scope laying around it can be made to work, but with decent optics available from $150-$500, why bother?


  1. Why not?

    Well… For one you’re bridging the gap. I really don’t recommend having tried that before.

    And two, even if you have a monolithic top rail, you don’t have to run a scout scope. That’s a pretty great reason as far as I can see. 😉

  2. I have the NcSTAR 2-7X32mm. long eye relief pistol scope on my Mosin Nagant 91/30, due to the bolt it was necessary to use one. Never thought about using it on the AR. I have one in 300BLK, maybe I’ll try it.

  3. I agree, it’s just like an ACOG, only with more economical options. It does put more weight forward, though, on an already nose-heavy platform, but if it feels fine that’s all that matters. As for the scope straddling the receiver and tube, I think having the one-piece scope base mount is definitely a good idea, as it should help protect the scope from damage if there’s movement between the two.

    Nice article on an idea that seems obvious once you hear it, wonder why no one thought of it before, or better yet: why didn’t I think of that!

  4. “The true “scout” rifles are bolt guns in .308 usually, although I think that the advances in .223 ballistics move the 5.56/.223 Remington in to the category as well.”

    This was Jeff Cooper’s reasoning:
    “The general-purpose rifle will do equally well for all but specialized hunting, as well as for fighting; thus it must be powerful enough to kill any living target of reasonable size. If you insist upon a definition of ‘reasonable size,’ let us introduce an arbitrary mass figure of about 1,000 lb (454 kg).”
    Have ballistics of .223 increased enough to fit this definition?

    1. Wait, so I have to meet a made up number because of reasons? Lolnope. You can kill 500 pound hogs pretty easily with a .223 though.

      1. Well, I’ve heard people say the .308 is “good enough for anything in North America”. I think that’s a good criteria for a “general-purpose” rifle, regardless of the number Cooper gave.

        I genuinely don’t know the answer to the question for .223 — has it improved enough to take on moose, grizzly, and any other North American species you might come across?

        Cooper’s assertion that 9mm is insufficient is no longer true, and I’m curious about the current state of rifle calibers.

        1. Honestly, no. I don’t think .223 even in it’s most effective loadings is enough for moose or bear. Could you? Sure, probably. But I don’t think a 75 grain .223 round would be an ethical choice for game that size.

  5. The scout scope on the AR15 is mounted too far to the rear of the carbine, move it forward it will work better.

  6. If the Trot Alpha rail were a monolithic rail/upper combo, sure. The Troy rail is actually three screws digging into a standard GI barrel nut, and doesn’t represent any sort of state-of-the-art rigidity in mounting. It doesn’t even measure up to the ALG or Daniel Defense rails, insofar as the first keeps two inches of contact with a fully-cylindrical barrel nut designed for mounting a rail, and the other bolts up.

    Troy’s rail is quality insofar as it’s alumimum and keeps your mitts of the barrel, but it’s not an optics mount, or even a comparatively solid rail – they’ve got tons of flex when tugged on or pressed.

    In short, the people who told you not to bridge the gap were right, your range test notwithstanding.

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