Why don’t more people use gas guns in the precision rifle world? I get asked that question a lot. Many military snipers use semi-automatic rifles for long-range work, but there isn’t a single shooter among the top 100 competitors in the Precision Rifle Series (PRS) using a semi-automatic rifle. Why not? Even though speed, maneuverability, and recoil management are huge parts to that game, the best shooters are all running bolt-action rifles. Some believe that is because AR’s can’t achieve the same precision as bolt guns, so the goal of this test was to quantify the precision difference between a couple of high-end gas guns and a custom bolt-action rifle.
6.5 Creedmoor Test Rifles
All of this started a few months ago, when I was contacted by Lewis Machine & Tool (LMT). They said they appreciated my tell-it-like-it-is, data-driven approach to testing gear, and they challenged me to compare their new large frame AR chambered in 6.5 Creedmoor to the best custom bolt-action rifle I had. Now that’s bold! I get approached to review all kinds of products, and virtually always decline … but their confidence definitely caught my attention.
A close friend of mine owns a large frame AR made by JP Enterprises, which is also chambered in 6.5 Creedmoor. That rifle was designed from the ground up for long-range precision work. So we thought it would be interesting to throw it into the mix as well, and see how it compared.
I looked for other precision AR’s offered in 6.5 Creedmoor to include in the comparison. The tactical, long-range competition world seems to believe that either 6mm or 6.5mm bullets are ideal maximizing hit probability for targets ranging from 400 to 1200 yards with minimal recoil (see the data). The 6.5 Creedmoor is a popular cartridge for that kind of long-range use, and we’re starting to see a few gun makers offer it as a standard choice on their rifles.
So I looked at other high-end AR manufacturers to see if they offered complete rifles in 6.5 Creedmoor, including: LaRue, Colt, Noveske, LWRC, POF-USA, GA Precision, Bravo Company, VLTOR, and Daniel Defense. Virtually all of them offer a large-frame AR-10, but most are only offered in .308 Win. So you could buy their complete rifle, but then you’d need to replace the barrel with one chambered in 6.5 Creedmoor for an apples-to-apples comparison. A few of them did allow you to specify other cartridges if you did a custom build. To my surprise, I only found one of those guys offering a 6.5 Creedmoor as a standard option, which was POF.
Our Brief POF Experience
Patriot Ordnance Factory (POF) did offer a 6.5 Creedmoor AR, and as luck would have it … a friend had one that only had a few rounds through it. However, we immediately encountered problems at the range with the POF rifle. Although we tried a few different types of factory ammo, the rifle wouldn’t consistently eject or feed rounds.
After talking to a few people about the problem, I uncovered that my buddy with the JP rifle had originally owned a POF in 6.5CM before he bought the JP … and he’d experienced virtually identical feeding issues with his POF. Our local gun store had sold many POF AR’s chambered in 6.5CM, and they had several customers return them with problems. I’ve been told that POF did repair each one and eventually get them in working order. But, we weren’t able to include the POF in the comparison because it had to be returned to the factory for repair.
The Final Line-Up
So here are the 6.5 Creedmoor precision rifles I was able to include in this comparison:
LMT Modular Weapon System (MWS)
Since Lewis Machine & Tool (LMT) was the catalyst for this whole project, I’ll start by looking at their black rifle.
The LMT rifle I tested was their Modular Weapon System (MWS) outfitted with a 24” stainless steel barrel chambered in 6.5 Creedmoor and 1:8 twist rate. The barrel is free-floated to maximize accuracy.
One of the cool features of the LMT’s Modular Weapon System is the quick-change barrel system. With an AR platform, it’s obviously easy to swap out the upper receiver to use another cartridge. But if you want that other upper to have the same fit and function, you either have to move your optics over or buy two identical scopes. It also might be ideal if you had the same handguard, rails, and accessories on the other upper receiver as well, which can get expensive. Sometimes when you swap uppers … you really just want a different barrel (for another cartridge, different barrel contour or length, etc.), and don’t necessarily want to swap all the other parts that are mounted to the upper receiver. Well, LMT has provided a way to swap the barrel out in just a couple of minutes. Whether you’re replacing a worn out barrel, or swapping to a different cartridge for training or mission-specific purposes … the end-user can do it in less than 5 minutes. LMT even includes all the tools you’ll need with the rifle.
In this design, the upper receiver just clamps around the shank of the barrel. So you just remove one screw, loosen another, and pull out the barrel. Insert the new barrel, and tighten both screws back up with the included torque wrench … and that’s it. You do need to pay extra attention to ensure there is no grease or debris on the shank of the barrel, and that it seats all the way in. But if you do that, you should be able to achieve the kind of precision this system was designed for. This is a similar to the approach Desert Tech uses on their bolt-action rifles, and they guarantee those to be sub-1/2 MOA (i.e. able to shoot groups under 0.5” at 100 yards with match grade ammo). So it’s a proven method to attach a barrel, even for precision work.
The LMT rifle features an uninterrupted, monolithic rail, which is conveniently indexed the full length of the rail. The monolithic rail allows you to mount optics and accessories in the ideal location, without having to avoid or bridge the area where the upper receiver stops and the handguard begins like you would on most AR platforms.
The handguard allows you to attach accessories at 12, 3, 6, and 9 o’clock. You wouldn’t be able to mount accessories at 45 degree positions without some type of offset adapter. Rails in a few sizes were included with the rifle.
This rifle came outfitted with LMT’s new DMR Buttstock, which is designed for the designated marksman. It features an adjustable cheek rest height and adjustable length of pull, which are high priorities for precision shooters. The flared angles on the cheek rest seemed to be more ergonomic for a natural shooting position and it helped me get a comfortable and consistent cheek weld. The DMR Buttstock also features a concealed picatinny rail on the bottom for mono-pod attachment. LMT claims the DMR buttstock was designed to replace current adjustable stocks in less than 20 seconds with no special tools required.
JP LRP-07 Long Range Precision Rifle
Now let’s look at JP’s offering in 6.5 Creedmoor:
JP Enterprises is well respected in the competition world, and for a good reason. Many gunsmiths use JP parts when building high-end custom AR’s, including parts like the JP trigger, low mass operating system, adjustable gas block, etc. Of course, those upgrades come standard when you buy a complete rifle from JP.
The specific model I tested was the JP LRP-07 chambered in 6.5 Creedmoor, which features a 22” barrel (my preferred length for this cartridge). It’s outfitted with a JP “Cryogenic Supermatch” barrel, which is described as a “medium” contour … but it is pretty thick compared to most AR barrels. The thick barrel definitely hints that this rifle was made for precision work.
JP offers a unique option they call a “Thermal Dissipater.” It is designed to keep the barrel cool through sustained fire, similar to how a heat sink on a computer processor keeps the chip from overheating. A heat sink is typically made from a highly thermally conductive metal like copper or aluminum, which encourages the transfer of heat from the source and spreads it over a much larger surface area to more effectively shed the heat into the surrounding air. In the case of the JP Thermal Dissipater, the heat sink increases the surface area by over 700%. JP says this can reduce the heat build-up near the chamber that causes throat erosion, which means the barrel could theoretically have a longer accurate life. It can also mitigate heat build-up in the handguard itself.
You can see the 2” tube handguard in the photo above, which is the JP Modular Hand Guard System. It’s 20% lighter than standard tubes, and unlike quad rails, it allows you to mount accessories in 45 degree increments all the way around. JP’s design is optimized for both comfort and function, with his philosophy of a “rail where you want them, not where you don’t.” The design seems similar to Magpul’s M-LOK system, but I don’t believe those two systems are compatible. JP does offer a ton of rail and accessory options for their handguard.
One of my favorite features on the JP rifle is the side-charging handle. JP explains this “self-folding, left-side charging handle affords additional leverage and makes it unnecessary to dismount the rifle to charge or clear it.” Some traditional AR shooters may hate the idea, but this setup seems fairly ideal for long-range work.
The upper receiver features an integral rail, which I’ve become a huge proponent of. As I’ve mentioned in other posts, I had lots of issues with one of my precision rifles that turned out to be related to slight movements in the rail the scope was mounted to. I sure enjoy the peace of mind an integral rail provides. Minimizing the number of parts and points of failure typically leads to better results.
The detail-oriented observer might notice this JP rifle is built on their streamlined competition upper receiver, which does not have a forward assist. They do offer a military version that has that feature, but their standard upper receiver does not.
And of course, the rifle comes with a crisp excellent JP trigger. It also features the JP Low Mass Operating System (LMOS), which reduces the felt recoil impulse.
One last thing to keep in mind is JP warns that their upper and lower receivers will not be compatible with other non-JP large-frame receivers. Of course, when precision is the primary goal, most shooters would likely go with a matched receiver set for a tight fit, instead of mixing and matching upper and lower receivers from different manufacturers.
This JP LRP-07 rifle as shown retails for $4,575 (when this was written). Keep in mind, this includes what JP calls a Presentation Grade Finish. To achieve this look they start by hand selecting a billet upper/lower combo that is hard coat anodized. Then they wet sand receivers by hand to give a brushed finish on the proud surfaces. They also apply a pristine polish to other parts like the barrel, hand guard nut, and a few other parts to match. That Presentation Grade Finish adds $800 to the cost and is purely aesthetic. This rifle starts at $3,299 with their standard black finish and options.
Surgeon Custom Bolt-Action Rifle
Since this is Precision Rifle Blog, and many of my readers prefer bolt-action rifles … I wanted to compare these AR rifles with a custom bolt-action rifle that was also chambered in 6.5 Creedmoor. I had Surgeon Rifles build this rifle for me just a few months ago as I was preparing for a huge barrel test. (The results from the barrel project are published in Bryan Litz’s new book, Modern Advancements Vol. 2.) But, this test was a great opportunity to use it as well!
This rifle is serving as our baseline for comparison, and isn’t the focus of this article … but I’ll just give a quick overview of the build:
- Action: Surgeon 591SA Repeater with TAC Knob
- Barrel: 22” Bartlein 5R Heavy Palma with 1:8 twist (Note: Although the photo above shows a fluted barrel, I actually used an identical barrel without flutes for this test)
- Chassis: Accuracy International AICS 2.0 with Victor Company ViperSkins
- Trigger: Jewell HVR set to 1 pound
As I mentioned, this custom bolt-action was built for me by Surgeon Rifles. Surgeon not only makes one of the best actions for a tactical precision rifle, but they’ve also been producing tack-driving complete rifle builds for the most demanding shooters (including USSOCOM and PRS champions) for more than a decade.
Honestly, this has become my favorite rifle. While a lot of that simply comes down to personal preference, I love just about everything about it.
This Surgeon custom rifle prices out at $5,134 as shown (excluding the bipod).
Shooting The Rifles
I started by breaking in and shooting these rifles a lot. I wasn’t sure if the LMT rifle had been broken-in, so I fired 300 rounds from it before I started the precision tests. I remember being impressed with the initial accuracy. During the break-in period, I fired 10 five-shot groups from the bench, which averaged 0.8 MOA. One of those groups was as small as 0.3 MOA, and the largest were a handful of groups at 1.1 MOA. I liked the ergonomics of the buttstock, and the trigger was better than most AR’s I’d used.
But unfortunately, I ran into some issues with the LMT rifle pretty quickly. The rifle would occasionally double-fire, meaning it would fire a quick two shot burst with one pull of the trigger. It originally only did that about once every 30 rounds, but over time progressed to where it happened every shot.
I contacted LMT about the issue, and they acted pretty surprised. After some digging, they uncovered the weapon they sent me was “a true T&E,” meaning it had been sent out for Testing & Evaluation to lots of people … and like a rental car, it may have seen some aggressive use. “So while the barrel is new, I believe the trigger and bolt carrier group (BCG) have upwards of 10,000 rounds,” they explained. So they mailed me a new trigger and BCG. Unfortunately, the replacement trigger wasn’t as light and crisp as the original … but it never double-fired, so I guess I’ll opt for safety and reliability over a lighter trigger. I do think we may have been able to shoot the LMT rifle a little better if it’d had a lighter trigger. I considered replacing the trigger with one of my after-market triggers, but then I’d be testing a customized rifle and not a LMT rifle … so I stayed with their stock setup for the rest of the test.
My buddy had already put a few hundred rounds down his JP LRP-07 rifle, but I shot it some prior to the precision test to get used to it. It was a pleasure. The trigger on it was as good as any AR trigger I’ve ever pulled. Now don’t get me wrong, it was a far cry from a light, crisp Jewell trigger on a bolt-action. But, it was a great single-stage AR trigger with a 3.5 pound pull and very little slop. The low mass BCG did seem to reduce perceived recoil. If I fired the JP and LMT blindfolded, I believe I could’ve told you which one the JP was purely based on the lighter recoil … but it wasn’t life-changing.
I also broke in the Surgeon rifle by putting 100 rounds down the brand-new barrel. In my experience, a bolt-action rifle doesn’t require as long of a break-in period as a semi-automatic rifle. A bolt-action is a much simpler device, with far less moving parts. Oh … and the custom bolt-action was a pleasure to shoot. The trigger was 5-star. The chassis was extremely comfortable and the recoil was quick and felt “smooth.” If you’ve never shot a rifle with an AI chassis, you should. It’s hard to quantify, but the chassis just seems to pass the recoil really cleanly with very little vibration or deflection. This rifle did weigh a couple of pounds more than the others, so that helped mitigate the perceived recoil as well.
The recoil force is sharper on a bolt-action than the AR’s, because gas-operated semi-autos spread the recoil force over more time. (Learn more in this post on recoil.) But, the recoil on an AR is longer and seems “choppier” than a bolt-action. That is because there is mass moving inside the rifle to eject the spent case and load the next round, and that cycling operation has distinct mechanical events that impact the amount of rearward force over time. (Watch a video illustrating the distinct events when an AR cycles.)
The Precision Test
To test precision of these rifles, I shot the rifles for groups at 100 yards. I used Hornady’s 6.5 Creedmoor 140gr A-Max Factory Match Ammo exclusively throughout break-in and testing. All of the ammo was from the same lot. My intent behind using factory match ammo was to ensure a level playing field, so you guys wouldn’t have to worry about variance within my handloads or if my handloads had been “tuned” to favor one particular setup.
Controlling For The Shooter
Then I also wanted to try to control for the shooter. One approach might be to shoot the rifles from a vise, and I do own one of those. But, in my experience I can get tighter groups firing from the prone position than I’m able to achieve from my vise. You may be as surprised as I was to learn that, but I’ve heard a couple other researchers say they had a similar experience. I’m sure there are great vises out there and guys who know how to get pinpoint precision out of them, but I guess I’m just not one of them!
So I elected the other approach for controlling for the shooter, and that is to average the results over multiple shooters. I recruited 3 other shooters to join me, and form the 4-man test squad. These other shooters weren’t just random guys off the street. One of them was my close friend, Rick, who consistently fires tighter groups than I’m able to coax out of a rifle. I’ve seen him shoot a sheet of 6 targets with 5 shots each, and every one of the groups measured under 0.25 MOA. I’ve seen him do longer strings where he puts 10 shots inside one 1/2 inch circle at 100 yards. Keep in mind that was done with a tactical rifle from prone … not a 25 pound, single-shot 6 PPC off a bench! Rick first entered the precision rifle world shooting high-end AR’s like those made by Les Baer Custom, and stuck to those for a year or two before buying his first bolt-action. So I’d bet he’s printed more tiny groups with an AR than anyone I’ve ever met.
The other two shooters are friends that are the gunsmiths at Mark’s Gunworks in the Dallas area, Mark and Chris. Mark’s experience has primarily been in the benchrest world, shooting in a DFW area shooting club with legends like Speedy Gonzalez. It was in that discipline that he acquired his impeccable (and almost paralyzing) attention to detail, and Chris has fully adopted Mark’s OCD tendencies when it comes to rifles. Both of them shoot in the local benchrest competitions, and both of them know what it takes to coax extreme precision from a rifle.
When you add me to that group, it rounds out our group of four shooters. We all gathered one day out at the range, and lined up all three rifles. All four shooters fired multiple 5 shot groups with each rifle. Some of us fired them from the ground in a prone position, and others fired them from a bench. I let the shooter go with whatever they were most comfortable with. The results are tallied up below.
Alright, alright. Enough talk. Let’s look at the results of the precision test. Instead of just showing one number to represent the average group size for each rifle, I wanted to show the range and variation of group sizes we shot. But, the challenge is there are typically one or two outliers that are either much smaller than the average or much larger than the average … so that can bloat the size of the range and make it less helpful. So I tried to represent the “typical group size” by showing the group sizes from the 25th to 75th percentile. That means 50% of the groups fall in the ranges shown, while the smallest 25% and largest 25% are excluded. This should give you a really good idea of what we experienced with these test rifles.
Now, I want to say a couple of things about the results. First, the lot of Hornady match ammo we used for this test (Lot #81494) had an abnormally high standard deviation (SD) in muzzle velocity of 19 fps. That was measured using a LabRadar Doppler Radar, which is accuracy to at least 1% of the measurement. For those less familiar with stats, an SD of 19 fps means that you could expect 95% of your shots to vary by up to 76 fps. That is a big number. If you used higher quality ammo or handloads capable of single digit SD’s, you’d likely be able to shrink those groups.
And I mentioned an issue I had with the LMT rifle where I had to replace the trigger, because the one on the evaluation firearm they sent me had excessive wear. Before I did that, I averaged 0.8 MOA 5-shot groups. LMT said they typically see these rifles hold 0.75 MOA or better, and my early results seem to support that. But, the replacement trigger was much heavier, and was honestly was no better than an average, factory AR trigger … meaning it left something to be desired. If you upgraded the LMT with a quality aftermarket trigger, then we believe we’d have shot that rifle better. We tried to coax the best precision we could out of the trigger they sent us, but the trigger can sometimes be the limiting factor … even if the rest of the rifle system is capable of more. We felt like that was the case here.
I was honestly impressed with the JP and thought it did well, although I’ve heard guys claim to get 1/4 MOA precision out of them. I’m not saying that is impossible, but I’ve just never personally witnessed a large frame AR capable of grouping 5 shots under 0.3 MOA for multiple successive groups. I bet I get to hear about some in the comments ;), but they seem rarer than the internet might lead you to believe!
And that brings us to the Surgeon. While the groups we recorded with the custom bolt-action weren’t anything to write home about, you can tell from the chart that they were measurably better than the AR’s. No huge surprise, but it’s interesting to see how much overlap there is between the bolt-action and the JP. I’m going to bet it surprises at least a few people to see how close an AR can come to the precision custom bolt-action rifle! Especially considering the Surgeon cost 36% more than the JP!
Let’s Put This In Context
Last year I wrote a series called “How Much Does It Matter?” and that included a post that looked at how much group size impacted hit probability on long-range targets. The results surprised a few people, including me. Look at the graph below, and notice that the increase in hit probability from using a 1 MOA rifle to 0.5 MOA rifle improves your odds by just 8% on the 10” circle at 700 yards, and by less than 4% on the 20” circle.
Don’t get me wrong, we all prefer tackdriving rifles. There is something innately satisfying when you stack 5 shots in one ragged one. But when you are comparing rifles like the JP (averaged ~0.7 MOA) to a Surgeon (averaged ~0.5 MOA), you’re just talking about a 2% improvement in hit percentage when it comes to these long-range targets. To learn more about where these numbers came from, read the post: How Much Does Group Size Matter?
It’d be ridiculous to expect every bolt-action to perform as well as the Surgeon custom rifle we tested, just because they operate with a bolt. We tested a factory Ruger Precision Rifle we tested a couple of months and it averaged 0.91 MOA five-shot groups with this same Hornady 140gr A-Max match-grade ammo (see that review). Not all bolt actions are created equal, and the one we’re comparing the AR’s to here is an example of a top-shelf, custom rifle. Just like these high-end JP and LMT rifles provide better precision than the average large frame AR (likely in the 1-2 MOA range), the Surgeon custom rifle doesn’t represent the average bolt gun. I mention that so we don’t mistakenly interpret these results as evidence that “bolt guns are superior to gas guns,” because that would just be ignorant.
This comparison can only really represent the three specific rifles we tested, and you could expect some variance in performance even with identical rifle of the same model. A larger test would need to be conducted with several randomly selected rifles of each model to draw more universal conclusions, but hopefully this test at least brings some objectivity to the conversation and puts some of these things into perspective.
Why don’t more people use gas guns in PRS matches?
I’ve been asked by a lot of people why more people don’t use semi-automatic rifles in precision rifle competitions. In fact, Bryan Litz asked me that exact question last year … so when a really sharp guy like that asks it, it’s clearly a good question! Honestly, I’m not completely sure. I’d bet if you put one of these AR’s in David Preston’s hands (the guy who won the PRS last year with the first perfect score) … he’d still do well in matches with it. Would he still win? Who knows! But, there seems to be enough evidence to show there are large frame AR’s available in the modern long-range cartridges like the 6.5 Creedmoor that are capable of competition level precision. I’ve still yet to see one that truly challenges the precision you can achieve in a custom bolt-action rifle, but the JP rifle we tested is clearly in the same ballpark and offers enough precision to be competitive.
A couple of months ago, I attended the 1st Annual Applied Ballistics Seminar Bryan Litz hosted in Michigan. One of the speakers was Shawn Wiseman, Director of the Precision Rifle Series (PRS), and he said he gets this question all the time too. He offered two major reasons he believed gas guns weren’t more popular in the PRS:
- Recoil impulse is longer, making it harder to spot impacts – Gas guns have a moving mass that must cycle back to the rear of the gun to eject the spent round, and then feed the next round into the chamber as it slams back home. That operation isn’t instantaneous, and it disturbs the rifle. Unfortunately, it is all happening during that short but critical time when the bullet is in flight. Shawn thought this longer recoil impulse on a gas gun can be a disadvantage in competitions like the PRS, because it can make it harder to spot your own impact. Seeing where your shot went is one of the most critical pieces of data a shooter can have. Even if you aren’t going to take a follow-up shot on that same target, knowing where you were off or exactly where you hit on the target can help you calibrate your wind call to increase your odds on the next shot.
- Risk of failure – While some gas guns are more reliable than others, bolt guns are much simpler machines with dramatically less moving parts. Before you call “B.S.” on this, realize Shawn is a special ops veteran who obviously has more experience with gas guns than most of us. So he is very familiar with their benefits and shortcomings when it comes to this area. While a gas gun may allow you to quickly put rounds down range, one malfunction during a match could destroy any chance of placing competitively.
Notice that Shawn didn’t even mention precision. Honestly, that surprised me at first … but considering the precision we found in our two AR’s, it stands to reason that raw mechanical precision may not be the limiting factor.
AR’s have radically improved over the past decade, in terms of both precision and reliability. That’s true for both AR-15’s and their large-frame brother. Computer-aided design and manufacturing, combined with a ton of competition in this space have pushed the industry forward. That’s why some believe it may just be a matter of time until AR’s catch up with the traditional bolt-action rifle. It’s still hard for me to imagine benchrest shooters firing gas guns, but nobody can predict what the market will do over the next 20 years.
There are certainly a lot of clear benefits of large-frame AR’s, and I hope this test showed that there are some GREAT options out there that are in the same league as a custom bolt-action rifle. There isn’t a clear, one-size-fits-all “right” answer, because the choice for what is the right tool for the job always comes down to application. Do you need the ability to make successive follow-up shots or more than 10 rounds of magazine capacity? Then you might lean towards the AR platform. Or do you want to eke out that last bit of precision, reliability, and ability to spot your own shots? In that case, you might lean towards a custom bolt-action.
The gap between the two setups just isn’t as large as it used to be, and seems to be closing tighter every year. I certainly appreciate all the effort the industry-leading manufacturers are throwing in this direction. Ultimately, that’s good news for us precision shooters, because it just means we have more great options!