Master Post for Semi Lightweight Barrel Shootout

This post is a master archive for everything surrounding the Semi Lightweight Barrel Shootout.  The test was conducted over veterans day weekend of 2016.  The data was processed over several weeks following and as a result it became some what hard for the casual observer to jump into.  When reading this information remember that during much of the ammo presentation we did not know which barrel or ammo had shot the best and we simply presented it as we found it.

 

The original post can be found @ SLW Barrel Shoot Out.  We fluctuated back and forth with the procedure for the test and it went from something we could do for a good time to concentrating on presenting everything clearly.

 

Testing went relatively smooth but we found early that we would be presenting fewer groups than we would have liked and the process was taking longer than we had hoped.  All barrels shot one ten shot group of each of the ten ammo selections.  Then they fired two five shot groups of each of the ten ammo selections.  Resulting in 60 rounds fired of each ammo and 600 match grade rounds being fired overall.

We went after the ammunition break downs first and each of the ten can be found in the links below.
Australian Outback 69gr

PPU 69gr

Black Hills 69gr

Federal Gold Medal Match 69gr

PPU 75gr

PMC 77gr

ASYM 77gr

Federal Gold Medal Match 77gr

CBC 77gr

IMI 77gr

The data from each of the ammunition types was compiled in a Data Summery found @ SLW BARREL SHOOTOUT AMMO DATA SUMMARY

Finally we compared the barrels using both Extreme Spread and Mean Radius

We also have an ammunition comparison adding price in as a factor found in the Price for Performance rundown.

If you enjoyed reading about this particular test share with a friend.  We learned a lot on how we wanted to share data in the future and how much we could attack in a given time frame.

Barrel overview using mean radius/average to center on targets

Before we talk about any of our own data I feel it is important to talk about what mean radius is and what it should mean in terms of accuracy reporting.  Any time someone talks about accuracy or precision as a general subject they quantify that using the term MOA.  MOA stands for minute of angle and is an angular measurement.  Generally speaking when they use this term they are talking about the measurement of extreme spread which they are showing the furthest outside two shots.  With an extreme spread you can have multiple ten shot groups that may look very very different but can be reported as the same size.

mean-radius-example

The above group illustrates how two groups which look very different could be misinterpreted.  The group on the right at .646 MOA extreme spread would be considered larger than the .643 MOA extreme spread on the left.  The are very close and could be a calculation error.  The reality is that the group on the left is much tighter with one outlier shot.  This isn’t necessarily a ‘flier’ or shot that should be removed from the group information but it surely shouldn’t define the entire group.  This is where mean radius comes into play.  By measuring each rounds displacement from the center of the group we can compare groups based off of the average deviation form the center of the group thus incorporating every round of the group rather than the two furthest groups.  The average to the center of the target on the left is .176 while the target on the right is almost twice as dispersed at .309.

Extreme spread has held its hold on shoddy reporting thanks to its ease of use.  Technology has taken over most aspects of our life but it seems to just be too easy for a shooter to approximate the furthest two shots (or often times eliminate the furthest and compare only the interior most groups)

Luckily there is great software out that we can easily process group sizes.  One such product is ontarget when you process groups through on target you can quickly compare extreme spread as with average to center instantly.  If you see other shooters presenting groups you can also quickly find a reference point and find the mean radius for comparison sake.

So how did our barrels and ammo compare when measuring every round of the group rather than just the extreme spreads?  (note some of the graphs were made by Ryan and are good.  The graphs with no Black Hills info are made by yours truly.  The computer genius)

Lets start with the Ammunition mean radius averages

ammo-group-average-all-atc

Right away we must remind that the ten round group for the Black Hills 69 grain was only 8 rounds for one barrel.  So 1/3 of the 10 round groups are slightly skewed and the combined data will be slightly different.  For that reason when we get to the barrel information there will be two graphics one with BH and one without.

Using mean radius we still see a rather tight pack among the full data of the ammunition results.  We still instantly pick up the larger PPU groups and find that it wasn’t a single or even a few misplaced rounds that sent the extreme spread to be the largest but the averages of the rounds to be routinely larger than the counterparts.

 

ammo-group-average-10-round-atcWhen showing just the ten round groups we see similar groups that do not line up as well as the others mostly the PPU offerings.  I feel compelled to remind again that the 10 shot group data for the Black Hills 69 had one excellent group of 8 rounds.

ammo-group-average-5-round-atcIn the five round groups we see the Black Hills is higher and is represented with a full sample size.

The barrel results are easier to read and compare.

5-round-group-average-atcI am leading off with the 5 shot groups as there are twice as many samples for them.  We also do not have any contamination in them.  The scale on this bar graph is at a very close examination.  There is only a difference of .04 moa over all the 5 round groups.  The three barrels all shot very well.

all-groups-average-atcWhen comparing all groups the criterion is about .05 moa tighter than both the BA and Larue offerings but this includes data for Black Hills 10 shot groups.

imageThe combined groups graph without Black Hills quickly shows off that I am a cave man that isn’t capable of simple computer tasks.  I couldn’t figure out how to put the numbers into the top and Ryan had actual things to do on a friday night. The figures are

Ballistic Advantage .584

Criterion .539

Larue .586

This doesn’t represent a huge change but it made me uncomfortable presenting data that was skewed.  I try to remind anyone looking at this that no groups were left out and any discrepancy from our method is noted.

10-round-group-average-atcTen shot groups with the BH data have been shown at a narrow range.  Remember that we are only looking at a difference of .11 moa from 1st to 3rd.

atc-10-shot-no-bhWithout Black Hills data again using my computer skills the values are

Ballistic Advantage .691

Criterion .607

Larue .660

The change from data containing all rounds and the data exluding the Black Hills 69 grain had no real change on the Ballistic Advantage or Larue barrels the Criterion had a shift from .5807 to .607.  This didn’t change much but is now representing a .09 moa change.

Below is each ammo broken down by barrel.  ppu-75gr-atc-barrel-data

asym-77gr-atc-barrel-data cbc-77gr-atc-barrel-data fgmm-77gr-atc-barrel-data imi-77gr-atc-barrel-data pmc-77gr-atc-barrel-dataaustralian-outback-69gr-atc-barrel-data black-hills-69gr-atc-barrel-data

It needs to be noted that the criterion 10 shot is mislabeled as a 10 shot when it is actually an 8 shot group.

 

ppu-69gr-atc-barrel-data

SLW Barrel Shootout – Ammo Data Summary

Yesterday we posted the final set of Chrono and Target data for PPU 69gr HPBT. Now we get on to the interesting side… interpreting that data and processing what it MEANS.

Through the posts about the ammo we compared two major components of the chrono data, the average velocity and the standard deviation. Here is how all of that compares in two, simple to read graphs:

ammo-average-velocity-16-barrels

ammo-standard-deviation-16-barrels

The IMI 77gr and Magtech/CBC both topped the field with an impressive 2639 fps (IMI) and 2637 fps (CBC) average over 60 rounds. IMI also took home the honors with the lowest standard deviation with a low 17.17 fps Standard Deviation with the two Federal Gold Medal Match offerings a close second (17.88 fps for 77gr and 17.94 fps for 69gr respectively)


Also during the ammunition posts we showed group sizes and averages for each individual ammo. We broke those average group sizes into two graphs, one for 5 shot and another for 10 shot groups so that you can easily compare all of the ammo’s to each other. The final graph is all of the groups for each ammo averaged together (5 and 10 shot groups both) and gives a good picture for the ‘total’ accuracy of each round.

ammo-5-shot-group-average

ammo-10-shot-group-average

ammo-group-average

Federal Gold Medal Match 77gr had the best 5 shot group average by a large margin, over .2 MOA smaller than the next closest Ammo. When it came to 10 round groups, Black Hills 69gr had the smallest group average by a large margin as well. It was interesting to see that the winners of the opposite category were rather average in the opposite category (FGMM 77gr had the 4th smallest 10 round group average and BH 69gr had the 7th smallest 5 round group average).

The best group of all of the testing was a .701 MOA group fired with Federal Gold Medal Match 77gr. It should be noted that there was only one 5 shot group over 1 MOA fired with FGMM 77gr. The only other ammo’s to fire multiple Sub-MOA groups were CBC 77gr (3) and PPU 69gr (2). The only ammo that did NOT fire a sub MOA group was PPU 75gr. The only Sub-MOA 10 shot group was fired with Black Hills 69gr ammo