This article is shared from a guy who used to follow our writing over at LooseRounds and was inspired by us. He started his site as a sort of blog detailing his journey to being a better rifleman and its evolved into something more like what LooseRounds used to be.
The gun world tends to move in cycles. Whether it’s because the industry wants to push the latest and greatest thing in order to keep customers coming back, or circumstances of the world shift, we see ideas come and go and then come back again. Lately, I’ve noticed a lot of buzz about SPR builds and a focus on precision AR-15 projects. This is coming after years of attention paid to short-barreled CQB rifles seen in the hands of GWOT Special Forces units taking down compounds. Prior to that, we saw a lot of attention on Recce Rifles, a shorter/lighter cousin of the SPR.
Why is this? I think it’s a few things working in tandem to give SPR and DMR builds their time in the sun again.
First, there’s been less attention on CQB-style raids and more on the light infantry and irregular warfare methods seen in Ukraine. People tend to be inspired by what they see often.
Second, when it comes to training and competition, it’s getting more and more difficult to stomach the ammunition bill for 1500 rounds fired over a weekend. Precision shooting naturally tends to have lower round counts.
Third, precision shooting overall has grown more popular with PRS, NRL and the like. Optics and barrels suitable for the task cost a fraction of what they did 10-15 years ago.
For beginners, I still think the best course of action is a basic general purpose rifle in line with the Minimum Capable Carbine. This is a great platform to build skills on, and it will do most things pretty well.
That said, if you’re interested in diving down the precision rifle rabbit hole, then let’s get started.
Defining the Terms
There really a lot of misunderstanding surrounding the designated marksman rifle and special purpose rifle. People often confuse the role and the rifle. Since adoption into the US military doctrine, the actual rifles have changed several times, often leading to confusion over what it actually looks like.
We’ve seen modified M-14 rifles, the EBR, 308 ARs like the SR-25, many variations of the AR-15 platform, and more. The role the rifle fills through all of this has remained relatively stable, though.
When I talk about a designated marksman, I’m specifically referring to an organic member of the squad. Their primary role is engaging targets, or supporting friendly movements, by accurate fire from intermediate ranges up to about 600 yards. This is primarily a fighting role that moves and fights with their squad. They operate much like an automatic rifleman, but equipped with a precision-oriented rifle rather than a light machine gun.
Let’s contrast that against a sniper, who fills a different role. A sniper is part of a separate team designed to observe, provide intelligence, and engage with precision fire. In the real world, snipers do a whole lot more observing and communicating than shooting. A sniper can, of course, do a lot of shooting, moving, and communicating, but it’s not their primary function.
Put another way, think of the sniper as if they were a special asset you could ask for if they were available, like air support, while the designated marksman is always in your squad.
If that’s not clear, don’t worry. I’ll get back to it in a minute and distinguish between the rifles. I think looking at a little history might help you out.
Origin of the Designated Marksman
History is full of examples of superior marksmanship producing outsized results. One of my favorite examples is the work of Daniel Morgan’s Riflemen during the revolutionary war as well as the Francs Tireurs of the French Resistance years. But for our purposes, let’s begin with World War I.
In the late 1850s, the first optical gun sights entered widespread use. By the early 20th century, they were fairly common on hunting rifles, especially in Europe. As the Great War ramped up, Germany fielde dedicated soldiers trained in camouflage, observation, and precision rifle fire. They drew these first snipers from skilled hunters, park rangers, and competition shooters.
The brutal warfare of WWI often took place between trenches an average of 50 to 300 yards apart. The sniper’s job was stealthily reaching a vantage point, watching the enemy trench, and killing high-value targets when the opportunity presented itself.
This tactic was immediately and brutally effective. The British entered the war with no such capability and paid dearly for until they started their own sniper school a few years later.
The Great War channel on YouTube has a great video detailing this portion of the war.
Some key takeaways from this video:
- Snipers operated alone or in pairs
- They provided observation and precision fire
- Training included camouflage and intelligence gathering
Those other elements take a long time to train, and sometimes all you need is a soldier with an accurate rifle and the ability to see further. Theorists believed there should be some kind of middle ground between the regular soldier and the sniper. A sharpshooter, if you will.
Again, the Germans were the first to it in World War II.
Forgotten Weapons did a great video highlighting some key examples of designated marksmen rifles over the years. The first true example is the German K98 ZF4.
This was a standard K98 infantry rifle equipped with a forward-mounted 1.5x magnification scope. The intent was for such a scope to adorn every infantry rifle, but German industrial capacity never caught up. The point of the forward mounted scope was keeping the breach clear for fast loading via stripper clips and a fast rate of fire, much like Cooper’s idea of the Scout Rifle years later.
This produced a rifle that added some precision capability to a standard infantry soldier. He remained as light and nimble as others in the unit and could use the same ammunition. This configuration saw limited use with actual snipers, but they preferred the higher magnification available in other optics with shorter eye relief.
Later in the war, the Germans fielded the G43 rifle. It was semi-automatic, magazine-fed, and equipped with a 4x magnification optic. It wasn’t terribly accurate, but it did represent what was to come in the future.
The Cold War
I think this is where the real magic starts to happen as each country develops is doctrine. Late in the 1940s, the US began attaching 4x optics to the M1 Garand. This model, the M1C, saw service through Korea. By the end of the Korean conflict, we switched to a follow-on model known as the M1D.
Both were intended for use by snipers but the interesting thing about the M1D was that it was a conversion kit. The idea was enabling unit-level armorers to take a current infantry rifle known to shoot well and quickly modify for a sharpshooter.
During Vietnam, the M1D faded away in favor of a scoped M-14 and a return to bolt-action rifles for snipers. The M-16A1 didn’t lend itself well to optics mounting, so the US military abandoned the idea of regular infantry rifles with magnified optics for a while.
But other countries did not.
The Soviet Union employed a different model for the sniper. While the traditional picture of a camouflaged stalker moving through the hills existed, it wasn’t the norm. Far more common was the “sniper” equipped with an SVD Dragunov and attached to regular infantry or mechanized units. These snipers were much more like regular infantry soldiers with additional marksmanship training and a fancy scoped rifle.
Understand that Soviet infantry doctrine revolved around massed shorter range weapons fired in automatic bursts. The soldier equipped with a scoped rifle filled the gap between short-range weapons and machine guns.
Failures in Afghanistan demonstrated that this type of “sniper” was not sufficiently trained in either marksmanship or fieldcraft for success, so the Soviets were forced to reevaluate their training programs. However, they still stuck with the philosophy.
The 1990s tested Soviet-era doctrine once again. As the Russians went into Chechnya, they followed the Russian doctrine of their “snipers” being fast-moving infantry that stayed with their units. On the other hand, the Chechens employed more traditional sniper tactics of camouflage, hides, and attrition.
It looked a lot like the fighting in WWII Stalingrad.
A 2002 article from Infantry Magazine discussed another effective tactic employed by the Chechens.
Some of the Chechens and their allies who were armed with SVDs deployed as actual snipers, while others joined three- or four-man fighting cells consisting of an RPG gunner, a machine gunner and, an SVD marksman, and perhaps an ammunition bearer armed with a Kalashnikov assault rifle. These cells were quite effective as anti-armor hunter-killer teams. The SVD and machinegun fire would pin down supporting infantry while the RPG would engage the armored vehicle. Often four or five cells would work together against a single armored vehicle…
Away from the cities, a Chechen sniper usually operated as part of a team–the sniper plus a four-man support element armed with Kalashnikov assault rifles. The support element usually positioned itself some 500 meters behind the sniper. The sniper would fire one or two shots at the Russians and then change firing positions. Should the Russians fire at the sniper, the support element would open fire at random to draw fire on itself and allow the sniper to escape.
– Lester W. Grau and Charles Q. Cutshaw, Infantry Magazine, Summer, 2002
This was about this same time that the US Navy SEAL teams started developing the in-house modified Recce Rifles. These “Sniper M4” rifles provided snipers an intermediate distance lightweight precision rifle that shared parts commonality with the rest of the team.
Lore says that the US Army’s 5th SFG toyed with the idea of accurized upper receiver groups during the mid-90s. The idea was similar to the SEAL’s Recce rifle, but it never gained traction in the Army. The program seemed like was going to die on the vine until the Marine Corps got involved.
In 1997, the USMC’s Warfighting Laboratory performed the Urban Warrior experiment to explore tactics for built-up urban areas. Then, from 1999-2004, Project Metropolis continued the experimentation. By 2002, the word got out that the USMC wanted a new type of rifleman in the squad, one equipped with an accurized M16 and magnified optic.
They called this new position the Squad Advanced Marksman (SAM). The Army quickly caught wind and created their own version known as the Squad Designated Marksman (SDM).
“Our fundamental SAM is a basic rifleman,” said Capt. Joe Tamminen, project officer. “That’s his first and foremost job. Now, we’re giving him some enhanced capabilities. By no means should the word ‘sniper’ ever come into play when we’re talking about the squad advanced marksman. That word is like voodoo.”
If the experiment proves successful, and Marine officials adopt the plan, a SAM will be his squad’s eyes and ears.
He’ll use standard-issue rifles with 4X scopes and night-vision sights to advise his squad leader how to move across the battlefield. The SAM also has a team radio, so he can be linked directly to the squad leader without needing to be next to him.
Both programs resulted in similar rifles equipped with free-floated stainless match barrels and magnified optics, typically a 4x magnification ACOG. As the Mk-12 Special Purpose Rifle program finished up, several of them entered service as well with the Marines and Army.
At some point along the way, the Army decided it wanted a 308 rifle to fill the role rather than accurate M16 rifles. There weren’t enough M110 rifles available, so the M14 came out of retirement bolted into a chassis system. The newly-dubbed M39 Enhanced Marksman Rifle (EMR) was only a stopgap.
The extended ranges found in Afghanistan validated the need for some longer range capability in the squad. The USMC’s answer to the problem was to issue ACOGs and free floated rails to every member of the squad, not just the Advanced Marksman. The SAM, in turn, received even more magnification.
Today’s Designated Marksman Rifle
All of that brings us to today.
As of right now, the Army and USMC diverged on their approaches. Both services still see a need to fill a role between a standard infantryman within the squad and a full-on sniper, but they differ on the weapons.
The Army elected to issue the HK G28, a variant of the 308 HK417 equipped with a 1-6×24 LPVO. A precision-oriented semi-auto 7.62 also offers many of the same benefits as a belt fed machine gun as far as suppression and chewing up cover, albeit with a lower rate of fire.
The Marines, on the other hand, stuck with the general issue M27 IAR, an HK416 in 5.56 NATO, and added the same Leupold TS30-A2 2.5-8×36 rifle scope found on the Mk 12. They approach the concept with the same mobility concepts in mind, but the SAM maintains weapons and ammunition commonality with the rest of their squad.
As you can see, once again, we have the same underlying philosophy but different approaches on how to get there.
Where does the SPR Come In?
So far, I’ve been talking about how the role of the Designated Marksman and associated rifle’s came to be. But what about the SPR?
The best way to think about the SPR is by who it was originally for. Kyle Defoor once pointed out that the “Sniper M4″ first saw operational use in 1993 by teams in Somalia. They typically looked like 16” rifles with Leupold 2.5-10 optics and free floating tubes. This “Recce Rifle” was a tool for dedicated snipers who needed a lighter package than the heavier sniper rifles of the era. The mission still required getting eyes on a target for observation, and the lighter 5.56 rifle still gave the ability to shoot, perform an assault, or break contact if needed.
The utility of such a light sniper rifle was obvious, and sparked the weapons program that became the Mk12 Special Purpose Rifle (SPR).
Core Traits of the DMR/SPR
As you can see from the history, there really hasn’t been a single version of the Designated Marksman Rifle. Rather, it’s more of a philosophical concept.
The intent of the designated marksman, from WWII to today, has always been to provide a longer range or precision fire capability organic to a team. This is not a sniper. The role is to fight along with and support friendly units in conflict. A designated marksman or squad advanced marksman does this using magnified optics and superior marksmanship.
On one hand, this is very similar to the role of a belt-fed machine gun, but sacrificing volume fire in favor of precision. On the other hand, it allows a squad the benefit of overwatch, where another member of the unit looks ahead for safe paths of travel.
Some of the core traits we’re looking for are:
- Light enough to move freely and fight along with the rest of the unit (this isn’t a “hide and wait” rifle)
- Capable of holding good accuracy over long strings of shots
- Free floated barrel with a good trigger
- Enough magnification to shoot further than the “average” engagement distance. In an era where nearly everyone is running up to 4x o4 6x magnification, this probably looks more like 10x, 15x or 18x.
While the roles of the designated marksman and sniper are different, there is overlap in the rifles themselves. The next step is defining the two distinct templates.
The Designated Marksman vs Special Purpose Rifle Templates
I think we’ve come along far enough that the terms are more or less settled. The primary distinction between a DMR and SPR is the cartridge selection. In turn, going one route or the other affects other factors, particularly weight.
For our purposes, a Designated Marksman Rifle describes an accurate semiautomatic rifle chambered in a full power cartridge like 7.62 NATO. For an AR platform, it requires a larger frame and different magazine than the standard configuration. The DMR is best suited to mid-range, between 100 and 800 yards, but could be used at even longer distances with the right load.
The Special Purpose Rifle no longer refers explicitly to the Mk12, but instead any lightweight semiautomatic precision rifle chambered in an intermediate cartridge like 5.56 NATO or .223 Rem. The SPR encompasses both the shorter Recce rifle concept and longer classic SPR/SAMR configurations. The SPR has a defined ideal use of close quarters up to 600 yards.
Both templates could be used in either a Designated Marksman or Sniper role, though the SPR is better suited at close-in fighting and observation. It’s also good for maneuvering with a team since it shares ammunition, magazines, and parts with the rest of the members.
The Everyday Marksman’s Designated Marksman Rifle
If we know we’re going to use a full power cartridge, then we have a lot of options that work well. With the M110A1, the Army elected to use 7.62 NATO for their DMR rifle. That may shift again in the future depending on the outcome of the XM7 project, but stick with me here.
Since you and I are not limited by the same kind of logistics overhead that the Army is, we can use whatever cartridge we’d like. 7.62 NATO, or match loads of .308 Win are suited to the job, but so is 6.5 Creedmoor and many other popular short action hunting cartridges. Personally, I think it’s best to stick with what the industry knows how to build well- and that’s either .308 Win or 6.5 Creedmoor.
When choosing between these two, consider how easy it will be for you to keep an ammunition supply and spare parts on hand. It used to be that .308 was the default answer here, but 6.5 CM has enough support and backing now that I think it’s a perfectly suitable DMR cartridge, of not slightly superior.
The main catch is that 6.5 CM has about half of the barrel life of a 308. If you don’t have spare barrels on hand, and I know most people don’t, it’s something to consider down the line.
A DMR is still a fighting rifle, so we don’t want to over-optimize for long range “sniper” work. The optic should span a mid-range magnification with a low-end on the 3x to 4x and a high end on the 15x to 18x. We should also be mindful of weight, as we’re already working with a large frame rifle. I think keeping the objective to 44mm or 50mm and tube diameter to 30mm makes the most sense here.
There’s an argument here for using a BDC reticle, and Primary Arms has a lot of interesting ones, but my preference is still for an MRAD-based “tree” reticle.
As for specific suggestions, I’ve got a few depending on your budget and desires. The lowest I’ll suggest here is the Primary Arms GLx 3-18×44, which retails around $750. Primary Arms has done a great job packing many desirable features into an affordable package.
Another great alternative for slightly more money is the Vortex Viper PST Gen II 3-15×44.
Stepping up to Japanese glass is the Brownells MPO 3-18×50. This scope goes on sale from time to time, often at prices even lower than the Vortex PST, and it seems like ridiculously good optic for that price.
Another interesting one is the Meopta Optika6 3-18×50, which ticks a lot of boxes including one of my favorite reticle designs for a DMR. I reviewed its larger brother and the 3-18x has always stayed on my radar since.
Beyond the ~$1000 price point, but still below $2000, things get more competitive. My top picks if you’ve got the budget to support it are currently, the Burris XTR III 3.3-18×50 with illuminated SCR 2 reticle, Steiner T6xi 3-18×56 with SCR 2 reticle, and Trijicon Tenmile 3-18×44 with precision tree.
DMR Barrel Selection
The barrel is the heart of the weapon, so everything I said about AR-15 barrels applies just as much to DMR barrels. The rules of physics don’t change just because you’re using a larger cartridge. The same rules of weight and barrel length must be considered balanced against the need for mobility in a fighting rifle.
When it comes to the barrel, the DMR is fundamentally a precision “fighting” rifle. There is still a need for accuracy, but you’re also going to have to carry the thing. For that reason, I err on the side of medium to light-heavy taper profile.
Something like a Criterion Hybrid profile barrel stands out to me as the right mix of accuracy and weight. I particularly like the nitrided 416r stainless models.
Struggling between 16″, 18″, and 20″ options? Join the club. In truth, I don’t think anyone has really nailed this down. Personally, I think 16″ makes sense if you plan on suppressing the gun. This is the route the Army solicitation went when they put out requirements for the CSASS (compact semi automatic sniper system) to supplement the 20″ M110 SASS. Without a suppressor, a 16″ barrel with full power rifle cartridge has a significant amount of blast. 20″ makes a lot of sense, especially if you consider a collapsible stock to go with it.
After that, pretty much the same rules apply to anything regarding rails, triggers, stocks, grips, etc. So much of that is personal preference. However, I do want to make the case for not building it yourself.
Build or Buy a DMR?
Unlike the AR-15, the large frame AR format is nowhere near as standardized. There’s a high probability that mixing and matching parts from different manufacturers ends up not working for you in the long run. For that reason, I think there’s a real argument for skipping the DIY process for a DMR and going right to a factory-built rifle.
It will probably cost more, but then you know you’ve got the backing of an actual factory warranty should anything go wrong.
My top picks for factory-built full power rifles are:
- LMT MARS-H (basis for the British Army DMR, BTW)
- Daniel Defense DD5 series rifles
- Seekins Precision SP10 series
- FN SCAR 20S
- KAC SR-25 series
- LaRue Tactical PredatOBR
The Everyday Marksman Special Purpose Rifle
With the heavier DMR defined, let’s look at the lighter SPR cousin. Originally, “SPR” stood for Special Purpose Receiver, with the intent being a separate modular precision-oriented upper receiver group that could sit atop any M4 or M16 lower receiver and provide the needed capability. Later on, probably about when the Mk 12 program finished up, the “R” became “Rifle.”
I mention that, because it might be helpful for you to think primarily in terms of the upper receiver as the “special” part.
When we’re talking about an SPR, then we’re looking at most of the same requirements of the DMR but in an even lighter package and focused on closer ranges. One of the big intents here is that the SPR shares the same ammunition with the rest of the squad, so that the user could quickly switch from a light sniper/advanced marksman role to a close assault role without issue.
That’s the military role, at least. As non-military members, I think we have some more flexibility.
SPR Cartridge Selection
By default, most people think of an SPR in terms of 77gr SMK cartridges like Mk 262 (developed in tandem with the Mk 12). Realistically, any quality accurate 5.56 load works well here, and I think there’s a lot of value in hunting as well as barrier-blind ammo selection for the role.
Then, should the need arise to abandon precision in favor of volume, the rifle is just as happy to feed whatever everyone else is shooting as well.
On the other hand, I think there’s a very interesting argument here for the SPR as a “light DMR” that still fits in an AR-15 package but shoots heavier bullets like 6.5 Grendel or 6mm ARC. If we think of the SPR as a separate receiver geared for the purpose, then it makes sense.
My biggest hesitation with the 6.5 Grendel and 6mm ARC route is a steady supply of ammunition as well as parts breakage. Both of these hot rod cartridges use a different bolt head with a larger face and less metal. While the problems seen early on seem to have been worked out, I think it’s important to know that there’s an increased risk of bolt breakage under hard use and hot loads.
For now, I think the best bet for a defensive SPR is sticking with quality .223 loads.
SPR Optics Choice
The SPR has a lot of overlap with the DMR. In fact, you could use any of the options I listed for the DMR and use them equally well on an SPR. However, I think the closer intended ranges of the SPR as well as the expectation for role flexibility translates to lower magnification ranges and lighter weights.
I break SPR optics choice into two categories: high-magnification LPVOs in the 1-8x and 1-10x range, and lightweight Medium Power Variable Optics (MPVOs).
On the LPVO front, I really like what Primary Arms did with the Compact PLx 1-8×24. There are many other options on the high end here, like the Nightforce ATAC 1.1-8×24, Vortex Razor Gen III 1-10×24, and Steiner M8xi 1-8×24. All of these are fantastic, and trying to nitpick between them isn’t really worth the time.
On the more budget-friendly end, I’ve been interested in the Athlon Ares ETR 1-10×24, Swamp Fox Arrowhead 1-10×24, and what Brownells did with the MPO 1-8×24.
That’s all just the LPVO market. For an SPR, I think there’s a better value in MPVOs paired with offset dots. Aside from the 3-18 and 3-15 scopes I mentioned earlier, the ones that stand out to me the most here are anything in the 2-10x or 2-12x range with a lighter weight. Particularly the Trijicon Credo 2-10×36 with mil tree, Primary Arms 2.5-10×44 with Griffin Mil reticle, and Nightforce NXS 2.5-10×42.
SPR Barrel Selection
The same rules apply to SPR barrels as DMRs and rifles in general. What you need the rifle to do dictates the barrel requirements. For general-purpose light carbines that get carried a lot and shot moderately, I suggest lightweight pencil barrels and light taper barrels. However, since SPRs have both an increased need for accuracy and a requirement to sustain that accuracy over many shots, we can’t be so light.
For an SPR, I’ll suggest at least a medium weight, and probably closer to a heavy hybrid taper. I’m ambivalent about stainless or not, that depends a lot on the manufacturer’s ability to make an accurate barrel. Generally, I think a .223 Wylde chamber with 1/8 twist offers the most versatility.
Some standout options for barrels include:
- Centurion Arms precision series
- Daniel Defense S2W series
- Criterion Hybrid profile
- Rainier Arms Ultramatch or Match series
There are many others out there given the popularity of the AR-15 platform, so listing all of the worthy ones would take forver. Ultimately, it’s nitpicky to sort between them.
The question of length comes up again, though. I think the same rules apply as for a DMR. I think it makes the most sense to either go 16″ or 20″ for length. 18″ is somewhat of an anomaly and exists mainly because of government bean counters. 20″ offers the most capability across the widest variety of ammo, while 16″ offers plenty of compactness and is far easier to work with when suppressed.
A 16″ is also easier to carry around separetely should you bring it along as a standalone receiver.
SPR Build or Buy
Unlike DMRs, I think the AR-15 platform is well enough standardized and understood that building it from the parts you want is the best route. Yes there are many factory-built accurate AR-15 rifles out there, but this is an instance where you can get exactly what you want without much trouble.
This was a long one. The DMR and SPR templates are both worthwhile investments, especially as you start getting into working with teams. I look forward to the rise in SPR/DMR-oriented competitions like what we’re seeing with Quantified Performance.
Ultimately, what I’ve suggested here is just my personal templates based on the history of use for both DMR and SPR platforms. You might have a very different idea, and that’s okay.
Get out there and shoot!
Matt is the primary author and owner of The Everyday Marksman. He’s a former military officer turned professional tech sector trainer. He’s a lifelong learner, passionate outdoorsman, and steadfast supporter of firearms culture.
A lot of info. to consider,that said,good article/thoughts.