Accuracy Evaluation of Six Different Noveske Barrels

AR/M4 AR Technical Discussion
1

Accuracy (technically “precision”) Evaluations of Seven Different Noveske Barrels.


Noveske 20” HBAR

This stainless steel barrel has an HBAR profile, polygonal rifling, a 1:7’ twist and the Noveske Match mod 0 chamber.

Using hand-loaded Sierra 55 grain BlitzKings, as a control load, this barrel turned in a 10-shot group with an extreme spread of 0.726" from the bench-rest at 100 yards… That’s not too shabby for an AR-15 with a barrel that has a chamber that “was developed to fire MK262 Mod 1 on AUTO in hot environments." For the Internet Commandos in our viewing audience, I also fired a 3-shot group at 100 yards. It had an extreme spread of 0.175”

Additional accuracy testing using the 20” Noveske barreled AR-15 and Nosler 77 grain BTHP at a muzzle velocity of 2800 fps was conducted in the same manner as described previously Three 10-shot groups were obtained from 100 yards. Those groups had extreme spreads of:

0.880”
0.857”
0.845”

for a 10-shot group average of 0.860”. These groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group which had a mean radius of 0.29”.

Noveske 16" SS Recon barrel

Testing was done at 100 yards from a bench rest. A Leupold VARI-X III set at 25X magnification was used for sighting. I obtained three 10-shot groups using one of my standard hand-loads for 77 grain Sierra MatchKings. Those three groups measured as follows:

0.81”
0.93”
1.01”

for an average 10-shot extreme spread of 0.92”.

These three groups were over-layed on each other using the RSI Shooting Lab software program to obtain a 30-shot composite group. The mean radius for this composite group measured 0.28”. Here’s a pic of the best 10-shot group of the 77 grain MatchKings.

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2

Noveske 16" N4 light Recce

I performed an accuracy evaluation of my Noveske 16” N4 Light Recce upper following my usual protocol. Testing was performed from a distance of 100 yards. Firing was conducted from a concrete bench with the free-float handguard resting in a Sinclair Bench Rest. The rear stock of the rifle rested in a Protektor bunny-ear bag. Wind conditions were monitored using a Wind Probe. A Leupold VARI-X III set at 25X magnification and adjusted to be parallax free at 100 yards was used for sighting.

Using hand-loaded, match grade ammunition I fired three, 10-shot groups in a row. The extreme spreads of those groups measured:

1.29”
1.18”
1.31”

for a 10-shot average extreme spread of 1.26”. I over-layed those three groups on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the composite group was 0.37”.

After firing the above three groups, I fired an additional five, 10-shot groups in a row using the same set-up for a total of eight, 10-shot groups. The average extreme spread for all eight groups was 1.24”. I over-layed all eight groups on each using RSI Shooting Lab to form an 80-shot composite group. The mean radius for that composite group was 0.39”.

Noveske 14.5” N4 light carbine

The 14.5” N4 barrel was tested in the same manner as described above. Three 10-shot groups fired from 100 yards using match grade hand-loads had extreme spreads of:

1.029”
1.360”
1.275”

for a 10-shot group average of 1.22”. As above, I over-layed the three 10-shot groups on each other using RSI Shooting lab to form a 30-shot composite group. The mean radius for that composite group was 0.37”.

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3

Noveske 16" SS Recon barrel in 6.8mm SPC

Accuracy testing was performed from a bench-rest at 100 yards using a Leupold Vari-X III set at 25 power for sighting. Wind conditions were monitored using a Wind Probe. All groups consisted of 10-shots each. Prior to testing the Hornady ammunition, I fired three 10-shot groups in a row using a control load that utilized hand-loaded 115 Sierra MatchKings. The extreme spreads for those groups measured:

0.99”
1.00”
1.12”

for a 10-shot group grand average of 1.04”. Following my usual procedure for evaluating the accuracy of ammunition, I overlayed these three 10-shot groups on each other using the RSI Shooting Lab software program to form a 30-shot composite group. The mean radius for this 30-shot composite group was 0.37”.

best 10-shot group of control load

Noveske 16" SS 9mm Parabellum barrel

For those that might not already be aware of this, Winchester’s website hosts some useful information about their Ranger-T series of ammunition. The website has an online terminal ballistics comparison tool that is quite informative. For example, if you are interested in seeing the difference in terminal performance between the 9mm 147 grain Ranger-T load and the 9mm 124 grain +P Ranger-T load in bare gelatin and after passing through four layers of denim (basically the IWBA test protocol) simply select those loads from a couple of drop down menus and voila!

The Winchester website also hosts downloadable “spec sheets” (in MS Word format) for all of the Ranger-T loads. Of particular interest to me was the accuracy “spec” for the 124 grain +P Ranger-T load. Winchester states the accuracy spec for the 124 grain Ranger load is an average extreme spread of 1.25” for (five) 5-shot groups at a distance of 50 yards. While I’m certain Winchester uses some type of machine-rested test fixture to obtain those results, that level of accuracy from factory loaded handgun ammunition is still extremely impressive. After reading the above spec, I was curious to see just what level of accuracy the 124 grain Ranger-T load would deliver for me.

Normally, when I evaluate the accuracy of ammunition, I shoot 10-shot groups. However, since Winchester’s accuracy spec was stated in 5-shot groups, I decided to follow their protocol for comparison.

The vehicle used for this accuracy evaluation was a Colt 6450 9mm carbine with a free-floated stainless steel Noveske barrel. Shooting was done from a concrete bench at a distance of 50 yards. Caldwell front and rear bags were used to stabilize the firearm. Sighting was done through a Leupold Vari-X III set at 10X magnification and adjusted to be parallax free at 50 yards. A mirage shade was attached to the Leupold. Wind conditions were continuously monitored using a “Wind Probe.”

Colt 6450

The Wind Probe

Prior to testing the Ranger-T load, I fired five, 5-shot groups of a control load consisting of hand-loaded 121 grain HAP bullets with the above set-up at 50 yards. Those five groups had extreme spreads of:

0.95”
0.97”
1.00”
1.07”
0.97”

for an average extreme spread of 0.99”.

In the same manner that the control loads were fired, I obtained five, 5-shot groups from 50 yards using the Winchester 124 grain +P Ranger-T load. The extreme spreads of those groups measured:

1.73”
1.88”
1.87”
1.89”
1.64”

for an average extreme spread of 1.80”. Not quite up to the level of Winchester’s “spec sheet,” but still very good for factory loaded handgun ammunition. While it is common convention to evaluate the accuracy of shot-groups using the extreme spread, a much more in-depth and reliable predictive indicator of the accuracy of shot-groups is the mean radius. Using the same shot-groups from above, I over-layed the five targets from each load on each other respectively using the RSI Shooting Lab software program. The mean radius was then calculated for the 25-shot composite groups formed using this method. The mean radius for the 121 grain HAP control load was 0.44” while the mean radius for the Winchester 124 grain +P Ranger-T load was 0.71”.

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Accuracy Evaluation of a Noveske 14.5” Afghan Upper

This is a Noveske assembled upper group based on the 14.5” stainless steel Noveske Afghan barrel. This barrel has a medium contour and a 0.750” diameter gas block journal. The gas block journal for this barrel is designed for Noveske’s low profile gas block and the journal is only one inch in length; standard length gas blocks will not work with this barrel.

The chamber found in this barrel is Noveske’s proprietary Noveske Match mod 0 chamber that “was developed to fire MK262 Mod 1 on AUTO in hot environments." The barrel has a 1:7” twist and polygonal rifling. The barrel extension has “M4” feed-ramps.

This upper comes with a Vltor MUR upper receiver with a forward assist. The barrel is free-floated in Noveske’s version of the SWS railed free-float hand-guard. Since the unwashed masses in my state are not allowed to own an SBR, this unit has an S.E. Vortex flash-hider pinned and welded to the muzzle.

I conducted an accuracy (technically, precision) evaluation of the Noveske 14.5” Afghan barreled upper from my bench-rest set-up following my usual protocol. This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any group reduction techniques (e.g. fliers, target movement, Butterfly Shots).

The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Pictures of shot-groups are posted for documentation.

All shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The free-float hand-guard of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade was attached to the objective-bell of the scope. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below.

For this evaluation, I used one of my standard match-grade hand-loads topped with Sierra 55 grain BlitzKings. When fired from my Krieger barreled AR-15s, this load has produced ½ MOA 10-shot groups at 100 yards.

Three 10-shot groups fired from the Afghan upper at a distance of 100 yards using the match grade hand-loads had extreme spreads of:

0.993”
0.941”
1.004”

for a 10-shot group average extreme spread of 0.98”. I over-layed the three 10-shot groups on each other using RSI Shooting lab to form a 30-shot composite group. The mean radius for the 30-shot composite group was 0.33”.

The smallest 10-shot group . . .

The 30-shot composite group . . .

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4

Unless I missed something, those accuracy results say a lot about the non-stainless, non-hammer forged Colt 14.5" SOCOM barrel. The Colt is more accurate than all of the above barrels tested except the stainless 20" Noveske 20” HBAR barrel and within margin of error for the stainless Noveske 16" SS Recon barrel => .92 average extreme spread compared to .95 for the Colt. Very impressive performance for a run of the mill Colt barrel.

http://m4carbine.net/showthread.php?t=59364

5

Great post Molon. Thanks for sharing your hard work!

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Must be nice to have so many “toys” to play with; no wonder I hate you!:smiley:

As usual, very nicely done.

7

Thanks, for sharing. Great report as allways.

8

It’s Threads like these that make the Internet worthwhile.:smiley:

9

Molon THANKS!
Your posts save so many of us a baseline for comparison and alot of wasted wondering;)

10

Nice work! What is “Mean Radius”?

When the groups are overlaid, are the centers of each group aligned with each other? Or do you align the centers of the targets?

11

Any shot group has a statistical center (or average center) which can be calculated from the coordinates of the shot POIs (as if they were points on the Cartesian plane). Note this point has nothing to do with the POA. The mean radius is the average of the distances between each POI and this statistical center. It is a better measure of rifle precision than maximum spread since it assigns less weight to anomalous outliers.

12

Molon,
I would LOVE to see you do some work with some of John’s SBR barrels.

13

I’d love to see him do a KAC barrel.

14

I understand what you’re saying. It seems to be the statistical version of a gunwriter “throwing out the fliers”.

I came across Mean Radius years ago, but no clear explanation was given

15

Before spouting anymore nonsense in this technical thread, please educate yourself on the subject matter.

MEAN RADIUS

Mean radius is the method of measurement of the dispersion of shot-groups used by the US Military for accuracy testing of ammunition. It provides a more useful analysis of the consistency of ammunition and rifle accuracy.

The typical method used to measure a group consists of measuring the distance between the centers of the two most outlying shots of a group. This would be the “extreme spread” of the group. We are essentially measuring the distance between the two worst shots of a group. Take a look at the two targets below.

Most people would intuitively conclude that the second target shown is the “better” group. Measuring the two groups using the extreme spread method, we find that both groups measure 2.1”. Once again with the typical method of measuring groups we are measuring the distance between the two worst shots of the group. This method tells us nothing about the other eight shots in the group. So how can we quantitatively show that the second group is better than the first? (Yes, we could score the groups using “X-ring” count, but this does not give us any differential information about all those shots in the X-ring.) This is were the mean radius method comes in. It will give us that extra information we need to better analyze our groups, rifles and ammuntion. If I just reported the measurements of the two groups above using the extreme spread meathod, without a picture, you would assume that the two groups were very much the same. Using the mean radius method shows that the second group is much more consistent. It has a mean radius of 0.43” compared to 0.78” for the first group.

Mean radius as defined in Hatcher’s Notebook “is the average distance of all the shots from the center of the group. It is usually about one third the group diameter (extreme spread).”

To obtain the mean radius of a shot group, measure the heights of all shots above an arbitrarily chosen horizontal line. Average these measurements. The result is the height of the center of the group above the chosen line. Then in the same way get the horizontal distance of the center from some vertical line, such as for instance, the left edge of the target. These two measurements will locate the group center.

Now measure the distance of each shot from this center. The average of these measures is the mean radius.

Once you get the hang of measuring groups using the mean radius it becomes very simple to do. While being very simple to do, it is also very time consuming. Modern software programs such as RSI Shooting Lab make determining the mean radius a snap.

The picture below is a screen snapshot from RSI Shooting Lab using the group from the above target. The red cross is the center of the group (a little high and right of the aiming point). The long red line shows the two shots forming the extreme spread or group size. The yellow line from the red cross to one of the shots is a radius. Measure all the radii and take the average to obtain the mean radius.

Mean Radius Demonstration

Let’s say you fired a 5-shot group from 100 yards and the resulting target looks like this. (The X-ring measures 1.5” and the 10-ring measures 3.5”.)

The extreme spread of the group measures 2.83”, but we want to find the mean radius (or average group radius.) In order to find the mean radius we must first find the center of the group. By “eye-balling” the target most people would see that the group is centered to the left of the “X-ring” and probably a little high, but we need to find the exact location of the center of the group.

Locating the Center of the Group

The first step in finding the center of the group is to find the lowest shot of the group and draw a horizontal line through the center of that shot.

Next, find the left-most shot of the group and draw a vertical line through the center of that shot.

Now measure the distance from the horizontal line to the other four shots of the group that are above that line. Add those numbers together and divide by the total number of shots in the group (5).

2.50” + 1.03” + 2.01” + 1.30” = 6.84”

Divide by 5 to get 1.37”. This number is the elevation component of the center of the group.

Next we need to find the windage component of the center of the group. From the vertical line, measure the distance to the other four shots of the group that are to the right of the line. Add those numbers together and again divide by the total number of shots in the group (5).

1.76” + 2.54” + 0.45” + 1.19” = 5.94”

Divide by 5 to get 1.19” This is the windage component of the center of the group.

Finding the windage and elevation components of the center of the group is the most difficult part of this process. Once that is done the rest of the process is a piece of cake.

Using the windage and elevation components, locate the position on the target that is 1.37” (elevation component) above the horizontal line and 1.19” (windage component) to the right of the vertical line. This location is the center of the group!

Determining the Mean Radius

Now that we have located the position of the center of the group, the first step in determining the mean radius is to measure the distance from the center of the group to the center of one of the shots. This line is a single “radius”.

Now measure the distance from the center of the group to the center of each of the rest of the shots in the group. Add the measurements of all the radii together and then divide by the total number of shots in the group (5).

0.85” + 1.35” + 1.38” + 0.84” + 1.61” = 6.03”

Divide by 5 to get 1.21”. This is the mean radius (or average group radius) of the group!

Using the mean radius measurement to scribe a circle around the center of the group gives you a graphic representation of the mean radius. This shows the average accuracy of all the shots in the group. This demonstrates why the mean radius is much more useful than the extreme spread in evaluating the accuracy of our rifles and ammunition.

16

very informative thread, thank you

17

As the new owner of a Noveske upper and probably a future purchaser as well, I greatly appreciate your work.

18

Thanks for this test. I’ve seen some fluted Noveske barrels. Have you done any tests on those ?

19

I suppose I deserve that slap on the wrist but take it easy on the Old Wolf. Your earlier explanation was brilliant and set off the lightbulb and shed light on more than one subject.

I said "It seems to be the statistical version of a gunwriter “throwing out the fliers”.

Seems as in has the appearance figuratively. Statistical as in based on factual data.

Not only did I clearly understand the methodology from your explanation, but at that moment I also understood what those gunwriters down through the years were trying to achieve by “throwing out the fliers”. Some knew in their gut that measuring extreme spread of groups with outliers was skewing the results. They would “throw out the fliers” in an attempt to achieve the same results as using mean radius. Perhaps some writers knew of mean radius but didn’t want to go through the effort of explaining it to the readership. I have always felt that “throwing out the fliers” was not an accurate method.

Yes, my statement was nonsense, but the nonsense was based on the practice of “throwing out the fliers” when measuring groups by extreme spread. I thought folks would get the inference, but I suppose I’m one of the few who learned to read from the writings of Skeeter Skelton, Elmer Keith and their contemporaries.

I meant in no way to disparage your work. I respect the time and effort required to collect this data using the scientific method

20

Unless I’m missing something, the rest of the above thread seemed to conclude that the 14.5 SOCOM Colt results were from a single barrel that did not appear to be representative of other Colt barrels.