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I try to be upfront with everyone that I think most shooters, especially new ones, are best served by a generalized rifle or carbine and lots of practice. This post is all about the recce rifle, but in my guide to buying your first AR-15 I mentioned several of the specialized configurations that are out there.

With just the US Military, there’s been a lot of variants, including the M-16 series (A1, A2, A3, and A4). For carbines, there’s been the XM177 that later became the M4 and the M4A1. We’ve got the Mk 18 CQBR and Mk 12 SPR, each serving very different roles. That’s not even getting into some of the test configurations, like the so-called M-16A5 or H6 models, which put 20″ A4 upper receivers on top of collapsible M4 lowers.

That last one happens to be a personal favorite.

In this post, I want to dig a little more into the role of the precision carbine. The two major branches are the Mk 12 SPR and the slightly less standardized cousin, the Recce rifle. Keep in mind the Recce was never a formal designation. It’s a label the civilian world came up with for what the SOCOM guys were doing.

Short History of the Recce Rifle

If you aren’t familiar with the lingo, “Recce” is British slang for reconnaissance.

In truth, nobody really seems to know the true origins of the SEAL recon rifle. The idea of putting a precision-oriented scope onto a standard infantry rifle is new by any means. But this particular thread of AR-15 development seems to have origins in the early 1990s.

US NAVY SEAL and early version of the recce rifle
A SEAL from Team 8 takes aim during an exercise in 1996. The rifle is an approximation of early Recce Rifle concepts. U.S. Navy photo by Photographer’s Mate Chris Vickers

The story goes that US Navy SEAL snipers began outfitting M4 rifles with precision scopes and barrels as in-house modifications for their units. Ultimately, that meant that there was no official specification for how they are supposed to look. It was a personal choice of the individual sniper.

The intent here was to bridge the gap between a standard infantry carbine like the M4, but not step up to the size and weight requirements of something like the M14.

Kyle Defoor, a former SEAL Sniper and current firearms trainer, gave the best approximation I’ve seen. The original thread is lost to the internet, but thankfully quotes still exist in some forums:

The original whatever you want to call them- Recces, SPRs, MK 12s (we usually just say “sniper M4″) had a 16” barrel, Leupold 2.5-10 and a PRI foregrip. They were first used operationally in ’93 in Somalia by our guys that were attached to our Southern brethren.

Did I mention his description was short and to the point.

Another SEAL in a related discussion laid out the role.

The base role for the Recce was/is to give eyes-on-target Sniper-Observer teams the ability to get close while providing a more capable/longer 5.56 reach and an emergency assault and/or break contact capability

Enter the SPR

At some point, the SEAL Recon Rifle grew in enough popularity that it left the hands of individual units and went up to NSWC Crane for further development.

At the same time, the Army took notice. According to the Small Arms Defense Journal, the Army’s 5th Special Forces Group had toyed with the idea already, but it never gained traction. The original Army concept was for an accurized upper receiver with a heavy barrel. Such a receiver primarily focused on precision but would also support by automatic fire as needed.

NSWC Crane went to the Army to ask for input for developing a new lightweight sniper rifle and cartridge to go with it. The AMU entered the picture and put their expertise to work.

The Mk-12 Special Purpose Rifle was the result. It originally had a 20″ barrel, but the Navy would not approve the procurement of 20″ match grade barrels since the supply system already said there were 20″ barrels available The fact that they were the less accurate M16A2/A4 barrels didn’t matter. So the barrel specification became 18″ and the bean counters were happy.

SOCOM officially fielded the rifle in the early 2000s with an 18″ rifle-gassed match-grade barrel made by Douglas. It had a fixed-length M16A1 stock, two-stage selective-fire trigger, and free floated handguard. There were two variants, the Mod 0 and Mod 1. There are subtle differences between them, but the most obvious is that the Mod 0 uses a PRI Carbon Fiber handguard and the Mod 1 uses the KAC RAS.

Both versions came with Ops Inc mounts and suppressors, and both were equipped with Leupold TS-30 2.5-8×36 optics.

The cartridge developed for the project was the now-famous Mk 262 77gr OTM.


The Mk-12 saw use all over SOCOM with the 75th Rangers, Special Forces Groups, Navy SEALS, and Air Force Special Tactics. But that doesn’t mean everyone was happy with it, particularly the SEALS. They saw it as a less-effective version of what they started with.

Kyle Defoor put it bluntly.

It went to 18″ quite frankly because the big Army got involved. Most of us that have a lot of time on one (myself included) think that 16″ is better for a number of reasons;
1. 2″ does make a difference, especially with a can.
2. weight (it’s not pounds at this stage it’s ounces) and remember that balance has a factor here too.
3. I’ve shot both together on the same range at the same time. I don’t really care what charts and scientists say, me and mine can hit just as good with 16″ as 18″.

The MK12 is ok as it comes, but, me and majority of the guys that were around me immediately shitcanned the fixed stock. Some would go with a Geisselle trigger too, and some would put a tube rail back on. All of these little touches were done in house at the shooters home team. 

So, in other words, officially making a program out of the SEAL’s Recce rifle turned it into a larger and heavier weapon that wasn’t as useful.

The Mk-12 Program later influenced the SAM-R and SDM-R programs for the Marines and Army.

Breaking Down the Modern Recon Rifle

I am not a clone dork.

By that, I mean that I don’t find enjoyment in trying to build exact clones of military configurations. I find the constant parts searching to be boring and tiresome. In a lot of cases, the specs for a particular rifle came out in a period where there just weren’t the number of options we have today.

The author shooting his own recce rifle
Shooting my own Recce Rifle

In fact, I argue that you can build a better rifle today than when the specs came out for something like the Mk-12 decades ago.

Instead, I prefer to look at the role a rifle filled and build towards it using available resources. So let’s look at the core requirements for a Recce Rifle:

  • Accurate enough to serve as a light sniper rifle
  • Durable enough barrel to support with an elevated rate of fire
  • Two-stage match trigger
  • 16″ free-floated barrel
  • Either a low profile gas block or front sight tower (both were common)
  • Adjustable stock
  • Variable power optic

You might look at this list and think, “You know…that’s an awful lot like most of the AR’s I see get posted in threads all over the internet.”

Well, you’re not wrong. The SEAL Recce rifle concept exerted a huge influence on the civilian AR world since 2010. Objectively speaking, it brings a lot capability to the table. It’s compact enough to live with but serve admirably at near and mid-range distances. For a lot of folks just getting into the game, it’s their ideal “SHTF-TEOTWAWKI” general-purpose rifle.

But everything comes with tradeoffs.

Let’s break down some of the key specs and my recommendations.

The Recce Rifle Barrel

The April 2012 issue of Shotgun News had a nice little article by James Tarr about the Recce Rifle and the his attempt to build his own. He mentioned that the original early 90’s NSW Sniper M4s usually had 16″ carbine-gassed match barrels produced by Lilja.

The official Mk-12 program used 18″ rifle-gassed barrels by Douglas.

Both of these are fine manufacturers who make accurate barrels. However, I don’t think that you should pursue crazy levels of accuracy here. A barrel capable of 1 MOA is more than sufficient for a light sniper role at less than 400-500 yards.

Mid-length gas was not a “thing” in the early ’90s, but it’s very common today. So, I’m thinking a 16″ mid-length is the ticket.

For the profile, the whole point here is something that’s lightweight and easy to carry. We don’t want to go down the path of heavy barrels since it defeats the lightweight purpose. But we also don’t want to go too lightweight because of the rate of fire requirement.

I think a nice medium-profiled barrel with a slight taper works well here.

For durability sake, we should absolutely pin the low profile gas block in place if you’re not using the FSB. A 1/8 or 1/7 twist will shoot all the common match bullets just fine, but a 1/7 gives you just a little bit more leeway if you ever plan on shooting hand-loaded 80gr bullets.

If you’re trying to be as close to the real thing as possible, the owner of Centurion Arms spent a long time developing the contacts to sell the exact barrel used on the Mk-12 and a shorter 16″ version.

The Recon Rail

The market has come along way since the early ’90s or even the early 2000s. We have an almost unlimited number of choices when it comes to rails and handguards.

Our priority here is weight and durability. The recon rifle often gets used with a bipod or other rests. We want to minimize flexion of the rail and provide good free-floating capabilities.

This is really personal preference, but I’m a huge fan of BCM’s rails these days. The mounting system works well and you can have it in your preferred flavor of Keymod, M-LOK, or 1913 rail.

I added a few more rails here, to include some personal favorites from Centurion Arms. There are plenty more on the market, but getting bogged down in Rail X vs Rail Y discussions really isn’t all that helpful.

Stock Selection

The original Recce Rifle design came from accurizing M4 carbines. The modified versions that sprang up as teams worked over their Mk-12 rifles usually got collapsible stocks as well.

As such, it seems fitting to use a collapsible stock here. If you don’t mind the extra weight, the UBR 2.0 provides the best lockup and is the most solid-feeling out there. It’s also compatible with the A5 buffer system, which is a big plus for me.

Aside from that, I say pick your choice from any of the quality makers out there like BCM, B5, Vltor, or Magpul.

Trigger Choice

I don’t see any reason to make this more complicated than the article I already wrote on the subject. Triggers are a highly personal thing.

A two-stage trigger is my preferred, and also what NSWC Crane installed in the Mk-12 rifles.


Really, the final step here is probably the most challenging. The optic you choose stems from how you want to use the rifle.

The original rifles had a wide variety of optics, but it seems the 2.5-8 or 2.5-10 magnification range is the most common. However, I’ve also seen 1-4, 1-6, and fixed low power magnification optics like the Elcan or ACOG used as well.

The thing to keep in mind here is that the Recce Rifle was not meant to be used at the long ranges a 10x scope is usually the answer for. However, only shooting at range like that isn’t always the role of the sniper. One of the quotes above highlights a lesser-known function of observation.

Think about scouting here. More magnification provides you with a bit more power to observe the target and provide support as necessary. Now there’s nothing stopping you from using slightly less magnification and also bringing along a nice set of binoculars. In fact, that’s probably the more comfortable option for most people.

I realize I’m bucking trends here, but the “killer feature” of FFP scopes is that the reticle subtensions remain correct throughout the magnification range. That’s great if you’re using them for lots of holdover or mil-ranging of a target. But at the 300-400 outer limit of what the Recon Rifle was designed for, you really don’t need that capability.

A second focal plane (SFP) scope is easier to use at lower magnification. I have a fairly nice FFP 2.5-10×32 optic that I love dearly, but it’s actually not all that usable below 5x if I’m in a hurry.

That said, as there are plenty of FFP optics on the market with smart reticle designs to help with speed at low powers.

Can’t You Just Buy a Complete Rifle?

Of course you can. The Recce configuration is very popular these days, so a lot of companies make good approximations right out of the box.

To me, pretty much any quality built A16″ R-15 will serve effectively as a Recce Rifle if you put the right optic on top. Most of the arguments flying around the web effectively come down to window dressing.

The real difference is the skill of the shooter behind the rifle.

Wrapping Up the Recce Rifle

my personal recce rifle
An older configuration of my Recce rifle

To close out this discussion, let’s review a bit.

The original SEAL Recce Rifle was an in-house modification to M4 carbines. The history goes back to the early 1990s. Since they were so individualized, there really wasn’t a spec. But we do know that Lilja barrels and optics in the 2.5-10 range were popular.

The original intent was to allow snipers to observe and provide rapid a lightweight precision-fire capability at moderately close ranges (300-400 yards). If needed, the recon rifle could serve for house clearing or traditional fire and movement.

If you wanted to build your own, we laid out some key elements to focus on:

  • 1 MOA-capable 16″ barrel of medium weight with a 1/8 or 1/7 twist
  • Collapsible stock
  • Match grade trigger
  • Free floated handguard of 10-13 inches in length
  • Magnified optic suitable to the task at hand

I hope you found this guide helpful. As always, let me know if you have any questions in the comments.

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Matt is the primary author and owner of The Everyday Marksman. He's former military officer turned professional tech sector trainer. He's a lifelong learner, passionate outdoorsman, and steadfast supporter of firearms culture.

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Dick CampenThe MarksmanAndrew PayneJMK ColoradoSunshine_Shooter Recent comment authors

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Matt, I am sure you know by now that say the word “optics” has the same effect on me as saying “Beetlejuice” has on… well, Beetlejuice.

Generally speaking, if you are up to it, we should do a podcast together some time. I am setting up to get one going if you are willing. Are you going to be at SHOT next week by chance?

Now, onto the Recce rifle and optics that fit it. All of my AR-15s follow that same Recce prescription reasonably closely with some branching out since I am not a clone dork either (great choice of words, by the way, did you come up with that?), but I like the general Recce configuration. Since I live in California (at least for a few more months), I can’t have a collapsible stock, so I have to either get a collapsible stock and fix it in one position or use a rifle tube which makes for softer recoil anyway. I built a couple of ARs using Ace Ultralight stock and with a medium length gas system, it is an extremely soft shooting configuration. I also can’t have a flash suppressor or a sound suppressor, so I use linear comps to divert the sound away from the shooter. For barrels, I find that ARP medium weight barrels are just about the best bang for the buck I have seen to date and thickness in the 0.7″ to 0.8″ range is a good compromise between weight and stability. To keep the balance right, I use very lightweight handguards and end up with the balance point right under the magazine which is just perfect for my needs given how much I shoot offhand.
I have built several guns like this in different calibers: two chambered for 5.56 with a Wylde chamber using 16″ barrels, one with a 16″ barrel chambered for 458SOCOM (because everyone should have one), and one with an 18″ barrel chambered for 6.5 Grendel. The latter would be my “one gun” if I were forced to have only one.

Now, let’s move onto the optics. Back when Recce concept was kicked off, modern 1-8x scopes did not exist, otherwise there would be no real question on the best scope type for this application, and there are good reasons you should be getting one with a FFP reticle even if you are only shooting inside of 400 yards. It is not just for drop compensation. It is also for lead, wind, shot correction for yourself and shot correction for someone else. The basic idea is to not have to worry at all what magnification you are on. Adjust he view through the scope to whatever happens to look good and use the scope in the same way whether your are on 8x, 6x, 4x or 5.5678x. For most things involving the reticle features you will typically be between 4x and 8x. The important part is to not have to worry where exactly between 4x and 8x you are. Now, if you think about reticles there are two thing you have to pay attention to: primary aiming point and secondary features (distance and wind holds, etc). With a SFP reticle, they are all always in front of you. With a FFP reticle, if you design it well enough, the secondary features should be disappearing from view as you decrease magnification. By the time you get to 1x, you should only see the primary aiming point with illumination helping it stand out. One good example of that is Burris XTR II 1-8×24. The FFP version of it is my current scope of choice given the bang for the buck aspect of it. There is a small holdover scale to use at higher magnifications and a 10mrad “circle of death” to use on lower magnifications (there are thigns I’d change in that reticle, but it works as is). The NX8 you linked above does a similar thing, except I do not like how that reticle looks on 1x with a dead battery. I have done a few articles on low power scopes and I keep on looking at them since this is a type of product I spend a lot of time with.

Sunshine Shooter

I’d listen to a podcast with Matt on it.

I totally agree with your position on FFP scopes. If I’m at 1x, I don’t want all that cross hair business cluttering up my view. I’ve held this view for a while but had no practical experience with this kind of optic until a few weeks ago when I finally purchased an SFP 1-6x. Now that I have some time on one, I find the reticle very distracting at 1x. I’ll put some sounds downrange in the next 2 or 3 weeks and really wring out my views, but I don’t think they’ll change much.


The development of very bright reticle illumination modules has changed the game somewhat in terms of reticle design, but I am sorta paranoid so I try to choose reticles that maintain reasonable visibility if your battery dies. That is an unpopular position these days, but I am sticking with it.

Mark Cutright
Mark Cutright

Is that a Turner Saddlery synthetic sling you’re sporting in that photo? I might have one of those…maybe.

Great article. I found myself agreeing wholeheartedly on, once again, using what works and not necessarily is rigidly prescribed by those who know better.

I think it might have been the first article I ever read of yours that convinced me of staying with the 16″ barrel as the do-all length. After sporting a 10.5″ with both a linear comp and then a suppressor, and this applies most in a shoot house that bounces that reverb back, I don’t feel like I’m leaving anything on the table using a 16″ barrel.

I do find that a low power variable takes about .25 to .5 second longer for me to acquire, but my round count is way lower on it. Even so, still more versatile AND, I might add, in the worst of situations the variable powered optic has a etched reticle that retains it’s function well after the battery wears out.


Another solid article describing origin and philosophy of use of the Recce design. Broad spectrum of versatility in the AR platform, you can build to taste and function. Eugene Stoner would be astonished to witness the platforms evolution, versatility and longevity.

Andrew Payne
Andrew Payne

Amazing article. Finally a well put together piece on the RECCE that doesn’t come in pieces from forums.

I notice all your reticle choices are some kind of crosshair MIL variation. I agree that for ranging and observation (recon!) that a mil dot style reticle is the best.

Is this why you chose those or is there another reason that BDC reticles don’t make your list?

Thanks, and again, great article! I’m enjoying all of your in depth blogs.


Great article. I bought a Ruger MPR with a Mk 12 influenced build but ive been seeing a lot of people talk about the 16″ vs the 18″ and now I’m think of maybe building a recce 16″ upper once the I finish with the 18″ upper is finished.

Sunshine Shooter

Great article. The recce build idea fascinates me, even though I don’t see myself building one anytime soon (too much overlap with other guns).

That being said, would it not help the lightweight aspect to use a lightweight/pencil profile barrel? Modern pencil weight barrels meet your 1 MOA requirement even when hot. Granted they would not hold up under full auto fire as well as a heavier barrel, but would that not be offset by the increased indoor maneuverability and reduced swing weight? Or do they not bring enough to the table when compared to a medium profile?

JMK Colorado
JMK Colorado

Regarding barrel profile, there’s been a return to a heavier profile by Spec Ops soldiers who see high volumes of fire – mainly to deal with the intense heat generated by sustained full-auto fire.
But what makes that interesting for civilians like me is that these heavier SOCOM profile barrels are also proving to be surprisingly accurate – and it seems to be due primarily to the stiffness imparted by the heavier profile combined with the short 14.5in length. These barrels are otherwise made to the same specs as normal USGI / Gov’t profile bbls.
So it would seem that profile is perhaps more important a consideration as other features normally associated with precision barrels.
This further validates your call for a medium profile barrel over standard USGI profile.

Great article, and fills in a few of the blanks that I hadn’t seen before. Thank you!

Dick Campen
Dick Campen

I have a URGI with an ACSS ACOG over a Geissele SSP trigger – No complaints & still smiling.

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