What Kind of Accuracy Can You Expect From Your Criterion AR-15 Barrel? Ammunition Quality Makes a Difference!

"What kind of accuracy can I expect from my Criterion AR-15 barrel?" 

It's a fairly easy question to ask, but formulating an educated response can prove to be a very arduous task. While many barrel manufacturers will offer a 1 MOA guarantee with their products, very few explain what this 1 MOA group entails. Is it a three-round group, a five-round group, a 10-round group, or some other pre-determined quantity? Is it fired off of a bench rest, a bipod, or some other fixture? What ammunition should be used in this testing to verify 1 MOA capability?

In our recent “Accurizing the AR-15” video series we outlined a number of internal rifle build variables that come into play when it comes to AR-15 performance. Headspace, component selection, and assembly methods will all have an impact on group sizes.

While external variables such as the shooter and environmental conditions will also play a role in group size, there is one additional internal factor in rifle performance that we have not yet described in detail: Ammunition selection.

We’re all familiar with the claims made on internet forums and social media groups where shooters claim their rifle builds will consistently shoot sub-MOA groups with bulk mil-spec ammunition. Oddly enough when most other shooters attempt to replicate this performance, they are unable to duplicate those results. There is plenty of reason for that. All other factors considered, poor quality ammunition will likely be a limiting factor in high-performance rifle accuracy.

To put this theory to the test, we sourced six different types of factory ammunition and a hand load previously worked up for a different rifle build. That particular load recipe was not tailored to accommodate this specific rifle barrel. The results of tailoring a hand load to an individual rifle barrel will be outlined in a future article.

Prior to our “Accurizing the AR-15” video series we went about establishing a benchmark for how these seven different loads performed in our rifle build. These “Before” groups were fired off a rifle supported by a Harris bipod featuring a Vortex Viper PST Gen 1 2.5-10x32 FFP through our SPRECCE rifle build.

Improvements made prior to shooting the “After” groups include an optics swap (to a Vortex Viper PST Gen 1 6-24x50 SFP), the addition of an Accu-Wedge, improved fitment during reassembly, and a switch from a bipod to a Sinclair front benchrest assembly and Edgewood rear bag for added stability. Component and assembly details can be found in our recent YouTube video series.

The ammunition selected for this test varies widely in price and quality. Each load utilized in this article was tested with a Magnetospeed V3 chronograph for extreme spread (ES) and standard deviation (SD) over a ten-round course of fire.

Each individual load was also accuracy tested both before and after the rifle was accurized. Accuracy was tested by firing three groups of five rounds with each load from 100 yards, with time allotted to allow the barrel to cool between each string of fire. The rate of fire during a string of fire was approximately one minute between rounds (this varied slightly depending on wind and mirage conditions during the course of fire). Weather conditions for both the before and after shooting sessions were fairly similar (75-80 degrees Fahrenheit with a steady 3-5mph wind). Extreme Spread (center to center) and Average to Center measurements were calculated through the OnTarget Windows application.

The below ammunition performance reviews detail the raw data collected over the course of testing. While there is currently much debate in the firearm industry over which measurement is the best indicator of rifle accuracy, the Extreme Spread measurement is the standard most commonly used at the time of this article’s publication. Extreme Spread data will be listed in the data analysis charts and graphs, although the reader is welcome to draw their own conclusions using either measurement method drawn from the raw data presented below.

The following describes the various different ammunition types selected, the price of each round type, and the reason we selected them for this test.

Load #1
Hand Loads

Sierra MatchKing Bullets

(Photo Credit: MidwayUSA)

Hand Load Recipe:
$.20 For 69gr. Sierra MatchKing
$.09 For 23.9 gr. Varget
$.03 For CCI #450 Primers
$.32/round overall

One of the benefits to handloading is that it typically offers improved control over load components and tolerances, allowing the loader to tailor their load recipe to a particular barrel. As time was at a bit of a premium for this testing, we selected a pre-defined load that had been used with great success with a different rifle build (the American Defense MFG UIC Mod 2 used in this video).

As each individual barrel will have its own preferred load recipe, we recommend fine tuning a unique load for each individual barrel to achieve optimal performance. Please consult your reloading manual for instructions on how to develop your own load recipe. As was mentioned in the introduction, we intend to describe this process and showcase the results in a future article series.

The current load used for this article incorporates a 69gr. Sierra MatchKing bullet, 23.9 gr. of Hodgdon’s Varget powder, a CCI #450 small rifle magnum primer, and PRIME Ammunition brass loaded just short of magazine length.

Another benefit to reloading is the lower cost involved in producing match grade ammunition. An argument can be made that the opportunity cost of time invested in reloading, as well as the initial setup and tooling costs may serve to mitigate this benefit, but it is hard to disagree that the cost of the components themselves will run for significantly less than factory loaded ammunition.

Muzzle Velocity Results:

Max: 2611 FPS
Min: 2584 FPS
Average: 2595 FPS

ES: 27 FPS
SD: 9.4 FPS

Accuracy Testing Results:

Before/After Accurizing Group Listing Group Size (ES in MOA) Group Size (ATC in MOA)
Before Group A 1.305 .523
Before Group B 1.155 .338
Before Group C 1.126 .396
After Group D 1.258 .361
After Group E .700 .301
After Group F .412 .124

 

 

Load #2
Federal Gold Medal Match:

 

 

Federal Gold Medal Match

 

(Photo Credit: MidwayUSA)


$1.00/round

Federal Gold Medal Match (FGMM) has long held the title as the leading factory match ammunition brand. With the historical performance we have experienced with this ammunition, we’re inclined to agree. For this test series, we elected to utilize their 69gr. Sierra MatchKing load. Featuring the smallest standard deviation and extreme spread of the factory ammunition tested, the only downside to this ammunition is the price. While the 69gr. load features a retail price of approximately a dollar per round, the 77gr. variant is normally priced slightly higher.

While Federal Gold Medal Match may not prove to be the preferred load of choice for your individual barrel, the odds are pretty strong that it should perform fairly well with most rifle builds.

 


Muzzle Velocity Results:

Max: 2684
Min: 2647
Average: 2662

ES: 37 FPS
SD: 14.0 FPS

Accuracy Testing Results:

Before/After Accurizing Group Listing Group Size (ES in MOA) Group Size (ATC in MOA)
Before Group A .767 .266
Before Group B .819 .284
Before Group C 1.051 .380
After Group D .557 .196
After Group E .838 .317
After Group F .707 .243

 

 

Load #3
PRIME Ammunition:

PRIME Ammunition

(Photo Credit: Prime Ammunition)


$.95/round

PRIME Ammunition is one of the more recent premium rifle ammunition brands to hit the market. PRIME utilizes load components manufactured in RUAG’s state-of-the-art production facility. These high-quality manufacturing processes allow for excellent factory match ammunition performance. Utilizing PRIME’s 77gr. OTM (Open Tip Match) load we were nearly able to replicate the performance of the Federal Gold Medal Match ammunition in both the velocity variance and accuracy department. Due in part to their new Shootscription service, PRIME is normally my personal go-to brand for .223 Remington ammunition.

Muzzle Velocity Results:

Max: 2454 FPS
Min: 2414 FPS
Average: 2433 FPS

ES: 40 FPS
SD: 14.2 FPS

Accuracy Testing Results:

Before/After Accurizing Group Listing Group Size (ES in MOA) Group Size (ATC in MOA)
Before Group A 1.043 .318
Before Group B .805 .300
Before Group C 1.156 .365
After Group D .805 .314
After Group E .962 .376
After Group F .783 .270

 

 

Load #4
Creedmoor Ammunition:

Creedmoor Ammunition

(Photo Credit: Creedmoor Ammunition)


$.78/round

Well known by national match competitors, Creedmoor Ammunition was founded as a division of Creedmoor Sports, a manufacturer and retailer that specializes in the distribution of a variety of match grade components.

I have long been a fan of their phenomenal .308 Win ammunition. That particular load is capable of consistent sub-half MOA performance through a number of our precision rifles. As an added bonus, their 175gr. .308 Win load configurations comes standard with Lapua brass!

Creedmoor’s .223 ammunition is priced to sell, retailing for quite a bit less when compared to the previous two manufacturers. While slightly outperformed by the PRIME and Federal Gold Medal Match ammunition in this test, the Creedmoor 75 gr. HPBT grouped considerably tighter than the bulk ammunition configurations evaluated.

Muzzle Velocity Results:

Max: 2621 FPS
Min: 2538 FPS
Average: 2571 FPS

ES: 83 FPS
SD: 25.9 FPS

Accuracy Testing Results:

Before/After Accurizing Group Listing Group Size (ES in MOA) Group Size (ATC in MOA)
Before Group A .654 .268
Before Group B 1.277 .451
Before Group C 1.816 .509
After Group D 1.130 .469
After Group E 1.141 .416
After Group F 1.213 .465

 

 

Load #5
Federal American Eagle XM193

Federal American Eagle XM193

(Photo Credit: Buds Gun Shop)


$.34/round

This is about as standard as ammunition gets for the AR-15. XM193 is loaded with Lake City brass to US military specifications. If you’re looking to replicate generic mil-spec performance, either the 55 gr. XM193 or 62 gr. M855 is usually the way to go. We have traditionally had better luck getting M193 to group slightly better than the XM855, and it normally costs a few cents less per round than its 62gr. cousin, so we elected to evaluate the XM193 for this test.

The phrase “mil-spec” has long been used as a marketing catch phrase in the firearm industry, but as of late many shooters have realized that the standards the military tends to hold for service rifles are frequently exceeded by higher quality commercial product options. The performance of the XM193 is no exception. It may be worth noting that the M16A4 features a 4.5” accuracy requirement at 100 yards as quoted in this Marine Corps Times article. Although XM193 ammunition is designed to fulfill military accuracy requirements, it by no means qualifies as match grade ammunition.

Muzzle Velocity Results:

Max: 3210 FPS
Min: 3161 FPS
Average: 3184 FPS

ES: 49 FPS
SD: 15.1 FPS

Accuracy Testing Results:

Before/After Accurizing Group Listing Group Size (ES in MOA) Group Size (ATC in MOA)
Before Group A 1.984 .798
Before Group B 3.260 1.156
Before Group C 2.992 1.196
After Group D 2.325 .817
After Group E 2.590 .977
After Group F 2.648 1.064

 

 

Load #6
Wolf Gold:

Wolf Gold

(Photo Credit: Sportsman's Guide)


$.28/round

Featuring a reloadable brass case and boxer primers, Wolf Gold offers decent performance for its price point. Velocities tend to trend slightly lower with budget ammunition, as powder charges may be reduced as a cost saving measure. This decrease in charge weight may also be encountered with poor quality remanufactured ammunition, which could cause extraction or short stroking issues on occasion.

None of those issues (outside of a slight reduction in velocity when compared to an M193 bullet of the same 55 gr. weight) were at all evident with Wolf Gold during testing, as all rounds cycled reliably through our test rifle.

Muzzle Velocity Results:

Max: 3102 FPS
Min: 3039 FPS
Average: 3064 FPS

ES: 63 FPS
SD: 21 FPS

Accuracy Testing Results:

Before/After Accurizing Group Listing Group Size (ES in MOA) Group Size (ATC in MOA)
Before Group A 2.461 .682
Before Group B 2.676 1.233
Before Group C 2.199 .649
After Group D 2.437 .982
After Group E 2.658 .911
After Group F 3.196 .855

 

 

Load #7
Wolf Polyformance:

 

Wolf Polyformance

(Photo Credit: Graf & Sons)

$.20/round

It doesn’t get any cheaper than this. Wolf Polyformance ammunition features a steel case with a thin polymer coating to aid in feeding and extracting. This is largely due to the limited flexibility of steel cased ammunition when compared to its brass counterpart. Featuring steel casings and Berdan primers, reloading this ammunition is virtually impossible. In an attempt to shave a penny or two off of the price of each cartridge, Polyformance incorporates a bimetal bullet (lead core with a copper plated steel jacket).

We didn’t encounter any failures during the testing of this particular brand of ammunition, but it isn’t uncommon to hear of shooters experiencing extraction issues with their AR-15 while using different types of inexpensive steel cased ammo.

There are a plethora of opinions regarding the cause of these failures, which could range from limited gas flow allowed by the reduced powder charges typically found with inexpensive ammunition, or by the inflexibility of the steel cases (which typically cause premature wear to the barrel and extractor).

Rumors persist that steel cased ammunition extraction issues could be caused by the traditional lacquer coatings (used as a rust preventative). There may be some truth to that rumor, as Wolf Polyformance advertises a polymer coating intended to aid in feeding and extracting when compared to the traditional lacquer finish.

Additional scientific testing would be required to effectively verify if there is any truth behind any of these rumors. Many shooters have no problem effectively cycling budget steel cased ammunition, but on the off chance that failures do occur with that particular type of ammunition, it might be worth experimenting with different brass cased factory loads to see if the case composition is the root cause of those failures.

Muzzle Velocity Results:

Max: 2,972 FPS
Min: 2,925 FPS
Average: 2,947 FPS

ES: 47 FPS
SD: 16.5 FPS

Accuracy Testing Results:

Before/After Accurizing Group Listing Group Size (ES in MOA) Group Size (ATC in MOA)
Before Group A 3.379 .978
Before Group B 2.529 .844
Before Group C 1.019 .412
After Group D 3.162 1.202
After Group E 1.789 .770
After Group F 3.856 1.496

 

 

Data Analysis:

 

Part 1: Accuracy Between Different Ammunition Types


When it comes to factory ammunition you normally get what you pay for. This principle is effectively demonstrated in the results obtained from this test.

As we can see from the data provided, performance from different types of ammunition can vary quite a bit. The results shown below in Chart 1.2 are pulled from our “After” data set, fired from a benchrest support and rear bag with higher magnification optics. This method of engaging the target is a bit more indicative of ammunition performance versus the “Before” results (listed in Chart 1.1) featuring a more field expedient rifle design.

The below charts [1.2 and 1.3] offer a clear image of how each of these ammunition brands perform. For the purpose of this test we will split these factory loads into three separate subcategories. The three high end brands (Federal Gold Medal Match, PRIME, and Creedmoor Ammunition) as well as the hand loads will be classified as “match grade ammunition” as they are all capable of generating sub-MOA five round groups at 100 yards through a Criterion barrel. The XM193 will be classified as “military surplus ammunition” as the XM193 is designed to replicate US military specifications. The two Wolf brands (Gold and Polyformance) will be referred to as “budget ammunition” for the purpose of this test.
Chart 1.2 showcases the average “After” five round group sizes with each type of ammunition at 100 yards, while Chart 1.3 lists the price per round of each ammunition type. It becomes immediately evident by reviewing these two graphs that there is an inverse relationship between group size and factory ammunition price.

 

 

Group Size Before Accurizing

 

 

CHART 1.1

 

 

Group Size After Accurizing

CHART 1.2

 

 

It’s worth noting that there is a fairly significant difference in price between the listed types of factory match and military surplus ammunition. There are a number of brands that bridge the gap between these two that are often marketed as budget or remanufactured match ammunition that normally perform somewhere between the two classifications in overall performance.
That said, in this test we’re working with a sample size of a single barrel. Each barrel will have its own pet load, so it is normally worthwhile to test a variety of different match ammunition types to see which load works best in your individual rifle. It is possible that some of the loads tested may perform better or worse than others through other barrels (even with the loads tested in this write up), although this test does serve the purpose of laying down an approximate benchmark pertaining to barrel performance with each different load.


Part 2: Accuracy Before and After Accurizing The Rifle Build


After posting our “Accurizing the AR-15” video series LINK we received a number of questions asking how much of a role build configuration and assembly play in rifle accuracy. We sought to assign a quantifiable value to this process by measuring group size before and after accurizing the AR-15 tested in this article.

Chart 2.1 showcases the “Before” and “After” group sizes side by side with each load tested.

 

 

 

 

 

Effect of Accurizing on Group Size

 

 

 

 

 

CHART 2.1

 

 

A strong correlation between group size and accurizing is evident in the highest performing ammunition tested (hand loads, FGMM, and PRIME Ammunition). This correlation grows weaker with the Creedmoor Ammunition and the XM193, but there is no correlation between rifle accurizing and improved performance with budget ammunition.

Change in average group size with match ammunition:

Handloads -0.405 -34%
FGMM -0.178 -20%
PRIME -0.151 -15%
Creedmoor -0.089 -7%

The average 100-yard five round group size (a cumulative total drawn from the four aforementioned match grade loads) shrank from 1.081 MOA to .876 MOA at 100 yards. This reflects a 19% average reduction in group size with hand loads and factory match ammunition after the rifle is accurized.
This leads us to believe that rifle accurizing will have a much greater impact on rifle accuracy with ammunition that offers consistent performance. Inconsistent ammunition will benefit far less from rifle build improvements than hand loads and high-end match ammunition, as the loose tolerances held on budget ammunition render precise fitment and improved build design irrelevant.

 

Part 3: All 55 Grain Loads Are Not Created Equal

 

55 grain .223 Remington loads feature the most common AR-15 bullet weight distributed commercially to the public. While many popular loads seek to replicate performance of the classic “Cartridge, 5.56mm Ball, M193”, the majority of commercial 55 gr. ammunition feature different specifications and offer varying levels of performance. Outside of the weight of the bullet, bullet design, commonality of powder selection and charge weight, case composition and thickness, and primer selection varies considerably from brand to brand.

In order to demonstrate this variance between 55 grain .223 loads we elected to evaluate three different types of ammunition for this test. Federal’s American Eagle XM193 offers a solid baseline for what we should expect from commercial clones of “mil-spec” ammunition. The two Wolf brands (Gold and Polyformance) demonstrated a significant variance in velocity when compared to the performance offered by the XM193, which will manifest itself in significantly different performance at longer range.

Federal lists the velocity of the XM193 at 3,165 FPS on their website. This fails to make mention of what type of barrel length, weather conditions, and twist rate this velocity was attained with, but that velocity did fall within our extreme spread measurements (3,161 - 3,210 FPS) so it would stand to reason that this standard was set by a barrel of similar length, with a similar twist rate, in similar conditions. Our average velocity with the XM193 sat at 3184 FPS, with a standard deviation of 15.1 FPS.

These initial results were matched by other velocity and barrel measurement studies of this cartridge, as well as the initial military specifications for the M193 cartridge (3,250 FPS from a 20” barrel).

Shifting to the Wolf Gold, a slight decrease in overall price can be noted ($.28 per round versus $.34 per round with the XM193). The Wolf Gold load incorporates many of the same features as the XM193, including Boxer primers and a brass case. While studies could be done to determine variance in case thickness, capacity, charge weight, primer performance, and bullet composition, the limited scale of this particular test applies only to muzzle velocity for each load. In that respect there is fairly significant variance between the XM193 and Wolf Gold .223 Rem load in this particular rifle.

While there are some differences in cartridge specifications between the 5.56 NATO and .223 Rem, Wolf advertises a velocity variance of only 10 FPS between the two (3,250 FPS vs. 3,240 FPS). Considering the traditional M193 specification calls for a 20” barrel length, one would assume that Wolf’s published velocity data reflects muzzle velocity generated from a barrel of that length. Based on this published data it would be easy to assume that we could expect to see velocities comparable to XM193 fired through our test barrel.

While past reviews have reflected slightly reduced velocity numbers from Wolf Gold, during our internal testing we were surprised to discover a fairly significant decrease in velocity between the XM193 and Wolf Gold (from an average of 3,184 FPS to an average of 3,064 FPS). The standard deviation in velocity also increased from 15.1 FPS to 21 FPS between the two aforementioned loads.

While this shift in velocity may not reflect much of a change in bullet drop at 100 yards, there is a slight increase in elevation variance at longer ranges. According to the shooterscalculator.com trajectory calculator at 300 yards we could expect to see an average change in elevation of 1.21” due to the velocity shift between the XM193 and the Wolf Gold. At 500 yards this shift in elevation increases to 5.36”.

A point of impact shift of this size would be easily noticed by a High-Power competitor using match grade ammunition, as each subsequent scoring ring increases in diameter by five inches on an MR-65 target. A five-inch shift in zero could account for an average decrease of two points per shot! That said, the three types of 55 grain ammunition tested were not designed with that particular application in mind. 

A more realistic comparison would involve the shooter participating in a USMC type qualification course engaging a B Modified target at 500 yards, where a five-inch shift in zero would be of little consequence if the shooter is holding center mass. The five-point scoring center features an overall height of 40”, which is much more forgiving. Ammunition of this quality is capable of generating groups in the neighborhood of 15” at 500 yards, so a deviation of 5” is fairly minimal when compared to the extreme spread typically encountered with mil-spec and budget ammunition.

While the difference in point of impact varies a bit between XM193 and Wolf Gold, that margin is tripled when comparing XM193 and Wolf Polyformance. Our average recorded velocity of 55gr. Wolf Polyformance was recorded at 2947 FPS, a full 237 FPS slower than the average velocity of the XM193 ammunition tested. The highest muzzle velocity recorded from the Polyformance ammunition was a full 189 FPS from the lowest velocity XM193 round fired.

Running the same ballistic calculator to compare the trajectory of the average velocity encountered with Wolf Polyformance and XM193 leads to a point of impact shift of 3.26” at 300 yards and 16.17” at 500 yards. The G1 ballistic coefficient of the Wolf Polyformance bullets also decreases slightly when compared to the previous two loads, shifting from .246 to .225. For nearly every marksmanship discipline (including the aforementioned USMC Qualification course example) a shift of this magnitude would require a significant adjustment in elevation to retain a functional zero.

Also noteworthy in the velocity shift is the maximum effective range of the lower velocity projectile. At 500 yards the XM193 bullet is still travelling at 1,604 FPS, well above the sound barrier. The Wolf Polyformance bullet is averaging at a comparatively slow 1,354 FPS at that same distance. While still supersonic, that velocity is on the edge of optimal stability of that bullet, as any round travelling below 1,340 FPS will begin to experience transonic effects.

It’s safe to say that all three 55 grain loads can be used interchangeably at shorter ranges with no significant point of impact shift (for casual plinking purposes). As the range increases the change in trajectory will increase significantly, especially between the XM193 and Polyformance loads.

Conclusion:

The findings of this test point us toward a few different conclusions. These details include the following:

1. You get what you pay for.

Higher cost ammunition tends to feature higher quality performance than than military surplus or budget ammunition when fired through a Criterion barrel. The exception to this rule involves hand loaded ammunition. A future write-up will explore the advantages of developing a unique hand load recipe tailored to an individual barrel.

2. Accurizing a rifle offers a noticeable improvement in the accuracy of quality hand loads and match grade ammunition.

This correlation is non-existent with military surplus or budget ammunition, likely due to the ammunition being the limiting factor in barrel performance.

3. Just because ammunition features a bullet of the same weight does not necessarily mean the bullet will feature a similar trajectory or accuracy potential.

When alternating between different brands or makes of ammunition, a re-zero will likely be needed. New trajectory data will also need to be gathered to ensure consistent hits at range. This variance in shot placement will increase significantly at longer ranges.

 

 

Disclaimer: Please note that the testing carried out in this article merely demonstrates anecdotal evidence. A sample size of a single barrel and the relatively small round count with each load are fairly limited in scale and effectiveness when attempting to confirm these theories with a high probability of certainty.

That said, the data generated and analyzed in this testing does feature a significant level of correlation with other tests carried out by a number of other reviewers and independent tests (many of which are linked in the above article). Our intention was to confirm these commonly held beliefs with our own limited scale testing.

If anyone is interested in running a more comprehensive comparative test we would love to hear your feedback regarding personal experiences with our products and various different types of ammunition. Feel free to share your information in the below comment box, or shoot us an email with the details at contact@criterionbarrels.com.

 

 

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