Comparison of All Test Optics: Test 4- Precision at 100

First of all, I apologize for my sparse posting lately.  I have some intensive life type business that is taking up my time, resources and mental energy.  This will probably continue until you happen to notice me posting more often.

Links to Individual Optic Test Results:

U.S. Optics SR-8c
Swarovski Z6i
U.S. Optics SR-4c
SWFA SS HD 1-6×24

This was a straightforward test.  The main idea was to test the precision of the shots with the scopes.  Secondary to that I wanted to use time as a measure for the ease of use of acquiring the sight picture, not only for each shot, but also when taking a position.  I started in standing with the bipod in the ready position and got into bipod prone at the timer signal.  Each shot was taken on a separate bull’s eye, and they were compiled into groups using On Target TDS.  I shot three strings on 10 shots for each scope.  I compiled the shots into 10 shot groups for each string and then finally into a total group of 30 shots for each scope.

The ammo for every test was Federal XM193, lot number v 55 Z531.  I would rather have used something that would offer better precision, but I only had the ball ammo in sufficient quantities for the testing.  I believe that if nothing else the ammo is consistent, which is really all I need to make a comparison.  The condition of the barrel for each testing run was comparable, as I cleaned it at the outset of the battery of tests for each optic.

I didn’t bother to conduct this test with the Aimpoint or to retest the SR-8c.  I could tell the Aimpoint was already out of the league of the magnified optics at 25 yards in the previous test.  With a bipod and rear bag I didn’t see the results of the SR-8c changing appreciably.  Also, I have a finite supply of time and ammo in this life, and I had to decide that neither was best allocated to test the obvious.

I considered showing the results in a variety of formats.  I had 3 ten round groups for each scope, for a total of 12 groups.  I looked at the results as a collection of individual groups from best to worst.  I looked at the average of the 10 round groups for each scope.  I finally decided that nothing really added to the total 30 round composite groups for each scope.  Here are those:




Swaro 30 Shot


30 Rounds

30 Round Group

I apologize that the size of the photo depends on how I cropped it at the time of the origial article, and that varied by how large the group was.  To make the results easier to digest, here are some pertinent numbers for the 30 rounds groups  They are listed in order from best to worst according to mean radius size:

Test 4 30 Rounds

I see the mean radius as the easiest number here to look at to get an idea of how the system performs.  It’s an apples to apples number, regardless of whether some scopes had wild ‘outliers’ and others didn’t.  Using mean radius as my standard measuring system allowed me to maintain some sanity and perspective when looking at performance.  There isn’t much guessing, and the number is pretty much what it says it is.

I still included the extreme spread of the groups.  Although it might not be as useful a statistical tool, as a shooter I still appreciate seeing a worst case scenario.  Also, a 3 round group extreme spread is worthless, but a 30 round group will tell you something.

In terms of time measurement, I think the average split time will tell you the most about the ease of use for the scope.  Establishing the position got quicker and quicker as I went, so the first shot time pretty much only tells you that in numbers.  Since I had to locate a new bull’s eye for each shot the split times are a better measure of how easy it was for me, and since the number is an average of 27 shots (30 minus the 3 first shots) of me doing something that comes pretty easily, naturally, and without thought, I don’t see much room for wild deviation, as in the previous test.  I listed the results in the order I used the optics.

Average Times

The clear, bright image and second focal plane reticle of the Z6i made it really easy to use for shooting a group at 100 yards.  It just edged out the SR-8c in terms of group size in terms of mean radius while the SR-8c barely had a tighter extreme spread.  The extra magnification of the SR-8c made it nearly as easy to use, its disadvantage being the large first focal plane reticle obscuring more of the target than was optimal.

The bold and complex reticle of the SWFA made it difficult to find the target center.  The target was black on white paper and bracketed nearly perfectly within the open center of the SWFA, but the SWFA reticle is very dark black while the target was rather thin and about as dark as you’d expect a laser printer to print black ink.  The SR-4c, being 4x was difficult in comparison to the SR-8c and the Z6i only because it had less power.

As far as precision goes, all other things being equal, a second focal plane reticle will be an advantage.  The other obvious advantageous attribute, all other things being equal, is magnification.  The Z6i would be my choice for this type of shooting at this distance.  It would be nice to have a bit more magnification, but not necessary.

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