U.S. Optics SR-4c Test Results

I apologize for taking so long between posts lately.  It’s been busy, and crunching the numbers for these test results is a tedious task.

Test 1: Single shots at 7 yards


Over 20 shots my average time was 0.9305. This was 0.105 seconds faster than the SR-8 (10.14%) and 0.1545 faster than the Swarovoski Z6i (14.24%). The fastest hit time was 0.75 seconds and the slowest was 1.28 seconds (shot #1- cold). The standard deviation for the times was 0.135 (SR-8c was 0.1415, Z6i was 0.1329). The hit rate was 85%, which was the same as the SR-8c, and just less than the Z6i, which had a hit rate of 95%. I believe that the speed number is more indicative of the performance than the hit rate, as hits are dependent on me not making mistakes. Misses typically occur because of some obvious lapse on my part, but I’ll leave that for you to decide.

The total points over 20 rounds were 95 and the average points per shot was 4.95. The ‘standard’ is 5 points per shot. This was the first optic to fall below that standard.  My standard for scoring is that over half the hole is in the scoring zone.

My hits over time score, what I’m calling “hit factor” was .91. Again, one hit per second would yield a score of 1. My points over time (point factor) was 5.32. Both of these scores were the best out of any of the optics tested so far. This illustrates that by factoring in time, even a slightly worse accuracy score can be overcome with some extra pep in the step.

This optic came out to be what I would consider significantly faster than any of the others so far. I probably collected enough data to see if the difference was actually statistically significant, but I have to confess that I don’t remember enough from one of the only useful classes I took in college.


Test 2: X-Box


I don’t recall that the feeling of shooting with this scope was markedly different than the SR-8, which is similarly laid out, but the proof is in the puddin’. The SR-4c was fast. My average time with the SR-4c was about a second faster than with the Swarovski Z6i, which had been the fastest up to that point.

Total x-box SR-4c

Average transition times for all four runs:

1. 1.22  Upper left (start)
2. 1.26  Upper right (right)
3. 1.10  Lower left (diagonal- down/left)
4. 0.84  Upper left (up)
5. 1.13  Lower right (diagonal- down/right)
6. 1.07  Lower Left (left)
7. 1.30  Upper right (diagonal- up/right)
8. 1.05  Lower right (down)
9. 1.09  Upper Left (diagonal- up/left)

Total Average Time: 10.04 seconds
Total Average Points: 43.25
Average points per shot: 4.81
Average hit rate: 81%
Average hits per second: 0.72
Average points per second: 4.31

While the actual hit rate was lower than the previous two scopes, which were tied at 86.11%, the times, which were again significantly faster more than made up for it according to the scoring system I’ve devised. Both the hits per second and points per second were higher than either of the previously tested scopes.

Test 3: DD25

I’ve determined that for me, at my current skill level, this drill is not a good measure of anything. It seems as though I can be quite consistent in types of shooting that I feel like I have some competence in. My performance in this drill is completely erratic, far beyond any differences that the optics might bring. The only trend I see is that I became quicker and less accurate the more times I shot it. I would need to work at this a lot to gain any competence with it, but part of my testing protocol is that I tried not to work toward improvement that would skew the results. I include the results only for the sake of completeness (and to keep me humble, as is the running theme of this blog).

DD25 SR-4c
Looking at this now I realize how sloppy I’ve gotten at this drill since then. Not good.

I completed 2 runs of this drill. My average raw points were 65 total of the 120 total possible (75 required to pass) . My average time was 27.25 seconds.  My average corrected points after penalties were 48.  My average hit rate was 73.33% (11/15).  My average hits per second were 0.4036697.  My average points per minute were 103.54 of the 300 minimum passing (34.51%).  Again, I shot faster, but this time it wasn’t fast enough to make up for the lower hit rate and points.

The trend with tests #2 and #3 is that I became more willing to take risks to shoot quicker. It seemed to pay off with test #2 but with test #3 being farther out it had the opposite effect. If I really wanted to get better at this I would move the target closer so I could get all my hits and gradually move it back.

Test #4: Groups at 100.

I began to feel a slight disadvantage with the reduction in maximum power in comparison to the other scopes while shooting groups at 100, but like many feelings it wasn’t justified by the results (which is why I’m going to rely on test results rather than fancy pictures and subjective opinion to do most of the talking here). There wasn’t much of a meaningful difference on paper in comparison to the other scopes, other than the extreme spread of the composite 30 round group was larger, which appeared to be caused by a high outlier in the second 10 shot group.  Other than that, some of the individual groups were smaller and some were larger.  The average mean radius was smaller than with the SR-8c, and the total mean radius was almost identical to that scope.  The second focal plane Swarovski Z6i was still the top performer in this category at this point in the testing.


Group 1

Group 2


30 Rounds


Group    Extreme Spread    Mean Radius

1.                 2.713                 0.725
2.                 3.639                 0.862
3.                 2.279                 0.662

Average Group

Extreme Spread | Mean Radius
2.849              0.805

Total 30 Round Group

Extreme Spread | Mean Radius
4.357              0.906


Test #5: “Long” Range Transitions

This, unfortunately, is the only photo I took of the rifle with the SR-4c on it.

A close up of the targets. The order, left to right was 270, 230, 330, 170.

I did not come into this test with any preconceived notions about scope power and performance, but I came out of the test with some ideas about it.

I made a couple mistakes in the test. First, I made a clerical error that led to a holdover error at the closest target (170). I wrote down 0.5 (which I think was the bullet drop in inches) vs. 0.1, which is that actual holdover in mils. Therefore my hold was too high. This shouldn’t have made too much of a difference, only about 2.44 inches if my hold had been perfect, but something else went wrong.  Three of my shots were off paper, and the center of the group that remained was much higher than it should have been.

Interestingly, at the time I was shooting this course of fire I did not expect to have poor results at all. I felt that although it was a little more difficult to see the targets, that I could see them well enough. I also felt as though my holdovers were on and my follow through was as good as it gets with me. When I noticed my mistake with the holdover mid-way through the course of fire, I determined that I should continue with the incorrect hold at 170, and that I could adjust the group down to figure my points. It just didn’t work out quite as well as I thought.

The second issue that popped up in this test was with the iPhone shot timer. I took a brief moment to check my holdover, which necessitated using a different app. I didn’t think that the shot timer would be affected, but it was. Therefore I only have time data for 15 of the 36 shots. At least I can still get an average time per shot.  That was 10.17 seconds, which was faster than any of the previous scopes, but that did not include the reload, which in this case was rather fast and efficient.

LR 170

LR 230

LR 270

LR 330

Distance | Extreme Spread (in.) | Extreme Spread (MOA) | Mean Radius (MOA)

170                                              Invalid Sample
230                  7.167″                           2.989                          0.899
270                10.528″                           3.378                          0.933
330                 8.788″                            2.567                          0.760

Distance | Points | Vert. Deviation* | Hor. Deviation | Total Deviation

170            14                           Invalid Sample
230            12              0.832                0.503               0.972
270            14              0.883                0.783               1.180
330              6              1.285                1.391               1.894

*Deviation of group center from intended point of aim (MOA)

I guess I could say that the good new is that some of the group sizes weren’t too bad. Some of the groups were better than with the Swarovski.  In fact, the average mean radius was better with the SR-4c than with the Swaro.  So in terms of precision the SR-4c did as good as can be expected when shooting a 4.2″ target at 4x out to 330 yards with reject military surplus ball ammo.

The bad news would be in the accuracy department (nearness of group center to point of aim).  I used points in this test to indicate the accuracy, and the performance basically fell off the wrong end of the chart in this case.  Even after adjusting my 170 yard target down by the equivalent of my hold error, the total score for all the targets was 46 points, compared with 107 and 102 with the SR-8c and the Z6i respectively.  It wasn’t wind.  It wasn’t mirage.  The earth wasn’t spinning any different than before.  I think I demonstrated my ability to use reticle holdovers in the Z6i test, so I don’t know what really went wrong.

In most respects the maximum 4x of the SR-4c fared pretty well with the requirements I placed upon it. I was quite disappointed when I completed the last test, but the decently sized groups just didn’t quite go in exactly the right place. I suspect that this could be mitigated with some time and training with the scope, but these tests are intended to get an idea of how easy the scopes are to use in comparison with each other. I found out that power matters, and it actually makes a pretty significant difference in how easy the optic is to use.


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