USO SR-4c (1-4x) vs. USO SR-8c (1-8x) for use on 16" DMR?

Tactical Gear Optics & Mounts
1

Hi there everyone,

First, let me preface my post by saying I generally hate advice threads like this because ultimately, the decision can’t be made by the hive and has to be made by the individual. However, I thought the options were distinct enough and my experience with them was lacking enough that the community may be able to glean some insight that I couldn’t. I also haven’t seen a thread on here (though I may have missed it in search) that compares two variable optics of such different designs and powers, so hopefully I’m not overlapping previously-discussed topics. Ok, with that out of the way…

I’ve narrowed down my optics choices on my 16" DMR to the USO SR-4c or SR-8c. My priorities on my optics are ruggedness/durability and battery life once a certain threshold of optical quality has been met, and I don’t think anything in the low-power variable market can match USO’s offerings in those categories except for maybe the upcoming VCOG. Thus, I’m not looking for any advice on other competitors, but rather a strict comparison of these two optics.

The rifle itself is wholly BCM with a 16" SS410 mid-length barrel, Geissele SSA, and free-float handguard. This is my DMR-style rifle, created to engage targets between 0-500m with more accuracy and precision than my chrome-lined BCMs touting Aimpoints and static-power optics (ACOGs), all while still being lighter and more flexible than a dedicated 18-20" SPR rig. It also will be fed a steady diet of 75-77gr pills, ranging in accuracy from sub-MOA to 1.5 MOA (but no higher), so having an optic that can fully utilize my barrel/ammo’s accuracy is important to me.

I’ve never used a 1-8 optic or anything like it. The closest I’ve come are 1-4x and 2.5-10x scopes. Between the SR-4c and SR-8c, it seems like there are some significant trade-offs:

[ul]
[li]SR-8c is approximately 6 ounces heavier (20 vs. 26 ounces)[/li][li]SR-8c is approximately 3 inches longer (9.25 vs. 12 inches)[/li][li]SR-8c has a 27 foot lesser FOV (110 vs. 83.25 feet @ 1x)[/li][/ul]

Overall, it seems like the SR-8c is heavier, bigger, and has a narrower FOV than the SR-4c, all as a trade-off for twice as much top-end magnification. Having never used anything similar to a 1-8x optic, I can’t tell if that’s a worthy compromise. Right now, my mind is telling me that it is, and if someone put a gun to my head, I’d go with the SR-8c, but my lack of experience makes me unsure.

Anyone have any insight? Does anyone here run a similar gun to this in 3-gun or other scenarios where they put a few thousand rounds down range between 0 and 300m+ per year, and if so, which of these two optics would you pick? Granted, I won’t be using this gun for competition, but it still seems to me that 3-gun would be a good place to test the capabilities of these scopes as they relate to my DMR-specific goals.

Thanks for the help, everyone. :slight_smile:

2

I was going to ask the exact same question for the exact same reasons. Weight is a major factor but I don’t think it’s something ultra critical. Reliability, rugednes and capabilities come first in my opinion but I just don’t have the experience to know all the different angles myself.

Sent from my SGH-T999 using Xparent BlueTapatalk 2

3

I had the same question essentially when it came to 16" DM Optics - I decided that anything heavier than 1.5# was going to be probably too unwieldy to be really effective as a 1x optic. Mine has some focus bias towards being a good close up rifle with the ability to stretch its legs, but the heavier 1-8x optics on a match 16" SS barrel are in the same weight class as an 18" with 2.5-10x type optic.

I really don’t feel that any of the 1-8x optics are ready for showtime in a light enough package to run on a 5.56 rifle - maybe the Mk8 on an SR-25 EMC because that rifle has such a wide performance envelope, but that’s the epitome of a compromise on both ends to pull off such a huge diversity of tasks with one package. I think the weight of the Mk6 on mine is basically the top end of what I would want, but if I was shooting out to 300-400m, the 6x would be primarily for observation, because the reticle works as well or better for me down at 4x, and having spent a lot of time behind a TA31RCO, the 4x really is fairly adequate for shooting, just doesn’t work as well for identification or observation.

I went as light as I thought I could in order to differentiate my recce setup from my Mk12 type upper, and it still feels barely better in every regard for being handy and more maneuverable. I still haven’t encountered the case where I felt that I ‘needed’ 8x magnification on this rifle, but that’s not to say it won’t come up, just that it’s not as common as I thought it would be.

4

I tried the US Optics SR-8C on my KAC SR-15 16" and it was just too heavy. With a BOBRO QD mount at 7.5oz that setup was pushing 2lbs, that’s just too much weight for the extra 2x. I have a Leupold MK6 1-6 on there now and it’s a far better match for the 16" DMR/Recce role rifle.

5

I was very temped to go to the SR8c, however my specific needs are 300 and in with the majority of it 25-200, I went with the SR4c. Lighter, and still reasonably able to go further if I do my part. There are other 1-6 [LP VX6, Kahles K16i, Vortex HD] options that I considered, but kept coming back to the SR4c.

6

Exactly. The VCOG, the MK6, and the Vortex HD II were all on my list to begin with, but I kept coming back to the USO as well. Now that I’ve sat on it, I’m leaning towards the SR-4c.

7

A large part of the problem is complete dis & mis information. Someone said, or it’s written somewhere on the internet it must be true. DQ it for other reasons, but not truth.

8

Interesting. That’s a great weight.

USO lists the SR-8c at 1.6 lbs (25.6 ounces) and the SR-4c at 1.24 lbs (19.84 ounces). In this case, it’s not just someone somewhere saying it so it must be true. It came right from the horse’s mouth.

Either way, the information is appreciated. Thanks, Voodoo.

9

I’ve seen multiple published weights for the 8c as High as 32 ounces but 22 seems to be the true weight

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10

This makes me wonder what the real weight is for the SR-4c since USO’s published weight is off by ~4 ounces on the SR-8c.

11

I weighed my SR-8C when I got it and it came in at 22.568oz. on my scale. The published weights on the USO website are obviously wrong. That said, 22.5oz. of the SR-8C compared to 17oz. of the Leupold Mark 6 is quite a difference, practically a mount in weight difference there. I love the SR-8C and I think it’s an amazing optic but I personally find that it’s more at home on a 308/SCAR 17S than on a 16" 556, YMMV.

12

13

As much as it sounds silly to complain about the weight - the other huge part is the eye box at higher magnification. It’s just hilariously small at anything above 4x in every scope I’ve test driven, so it makes the higher range of the magnification get used a lot less often. The less you use that higher magnification, the sillier it seems to be lugging around the equivalent of adding a T-1 in a mount to the weight over the lighter 2.5-10x offerings (e.g. NF NXS 2.5-10x Navy Mk12 type).
Consider also that the mount is going to be another 7-9oz, depending on brand (LT-104 is about 6.9, LT-135 closer to 7.4 in 34mm; something like the ADM Recon-H in 34 is 9.1)

If USO can churn out an SR-6 with a good reticle, good illumination, and under 20 oz they’d have a world-beating optic until every other firm copied the formula (or fixed their similar stuff). The weight of the glass and the eyebox compromises to make any optic good at 8x and 1.1x are just to huge, even in the 35mm tube format is just too crazy to have them be affordable, lightweight, and still be aimpoint-like at low magnification.

I just think it’s amusing that TejaxMTB tried so many of the combinations I have, plus more, and our ‘ideal Recce’ rifles are so close to each other in execution.

14

Which is why a lot of people don’t use the T-1 / H-1 or La Rue mounts. We have been there for more than 5+ years now. In fact exactly no one I know uses that combo & has not been for some time now. We & other’s use lighter mounts like AP (@2.98 oz.) / NF UM, a 1.5 oz Doctor Optic / L3 / Burris or similar w/ shroud. Minimal weight, robust enough, no distortion, does not fog w/ anti-fog, long battery life, daytime illum. But I forgot people here don’t really read. Scope weight of 17 oz + 1.5 ozs @ approx. 18.5 ozs. & been doing it for over 5 years this way, but some are slow on the uptake.

15

I’m not sure if I’m tracking - I was referring to the weight of the mount for the primary optic being in the 7-9oz range, which is unavoidable weight for using a low powered variable optic. The point I was making was that a difference of 6oz is literally enough to run the lighter optic AND a piggybacked Aimpoint micro (on whatever other mount that offsets the aimpoint), let alone using the true micro sights like the Docter, Deltapoint, RMR, and others, so if the higher magnification range was more important, it would be the same weight to run a light 2.5-10 optic with a secondary reflex optic and mounts for both as it would to run one 1-8x optic with its mount.

FWIW, my lowly Mk6 still only feels like the glass is performing well from the 2-4x range, and then dialed all the way down to 1x it gets useful again; for fast stuff the lower zoom works just because the funky illumination works fine in Bindon Aiming mode (for me) at 1x. The FOV and Eyebox really only feel right in the mid range of the wider magnification range optics to me, the 1-4x offerings from many companies seem to exhibit this issue the least, but the wider magnification spread optics I’ve tried, it becomes quite pronounced to me that either the FOV is clipped, or the eyebox is too restricted being too close to the ocular lens and getting bad eye shadow. If you don’t experience this, then please discard my input on the subject, but this is what I’ve observed across the board on these, and really only like my Mk6 because it chooses to suck less at the lower magnification (IMO it’s a pretty good, slightly overweight 1-4x optic that can be cranked up to 6x and be a mediocre optic up there; the only improvement over the Mk4 1.5-5x are the reticle/illumination and almost 1x)

Either way, the lightest 1-8x SR-8c configuration with a usable mount (iirc the NF Ultralite in 1.5" over bore is around 6oz) is going to be in the 1-3/4# - 2 # class of optics, while svelte 1-4x are under 1.5#; I haven’t had time behind the SR-8’s, but the 30mm main tube can’t work that astoundingly at both 1x and 8x no matter how awesome the glass, so unless I need the capability at both extremes (easier to justify with a 16" 308) that’s $2.8k of optics/mounts I can wait to look into.

For me, 1-8x optics just aren’t light or user friendly enough for a rifle that ballistically runs out of gas at soon as 5.56 does yet - with a long enough match barrel to really shine when used at 8x, this is a 10# rifle with major handicaps when used within 25yd; or on a smaller lighter rifle (8.5#) the optic is going to feel like a boat anchor, as the optic is almost a quarter of the overall weight. It seems dumb and niggly to worry about a difference of a pound and a half, but if you start off with the 1-8x optic as the assumption, might as well aim for the 11# rifle that can reach to 800m reasonably well with 175gr match rounds as packs better inherent intermediate barrier penetration by virtue of the caliber to make up for part of the ungainly handling. Since we’re talking optics north of $2k, it’s not like a 7.62 rifle is out of the realm of possibility - but this is why I feel an SN-6c would be THE recce offering from them.

16

Since wer’e just spitballin’,
I’m not sure what is not absorbing or assimilating.
Nightforce UniMount A190 - 1.125" Height (high) - 4.576oz that is the weight that NF specs & I did weigh one at one time to verify & it is correct plus or minus a gram.
https://www.m4carbine.net/showthread.php?123319-lightest-uni-type-mounts

Right there is 2-4 ozs UNDER your posted quoted weight. The Aero Precision is even less. Spec’d out @ 2.98 ozs.
http://aeroprecisionusa.com/scope-mount/ultralight-30mm-scope-mount.html

So if we add up the known weight of a SR8s @ 22 ozs. plus 2.98 ozs for AP Mount we are ballpark @ 25 ozs. Next add a MRDS @ 1.5 with streamline TVNC uber lightweight 30mm scope MRDS mount you are pushing just over 28 ozs. total weight. Swap that configuration for a NF 2.5x10x24mm & it specs. to 17 ozs+2.98 AP mount=20ozs+1.5 Doctor Optic MRDS=21.5ozs.+TVNC SAR 3PS mount for Doctor Optic MRDS & now were at total combined total package weight of approx 23 ozs.
Which is under the Leupy MK6’s Scope spec’d weight alone of 23.7 ozs. sans, ANY mount you pick.

TVNC 3PS mount here:

What makes the SAR 3PS mount sweet is that you can can’t it ANY infinite 360 degree angle for minimal lag time transitioning for shots.

let’s move on to your example. Leupold MK6 1.1x8 CQBSS. Great optic. No argument there. It specs. @ 23.7ozs. actually weighted on on a customers gun I built & it actually came out to slightly more than that @ 24+ ozs. (wish now I kept the pic to show). So if we add a La Rue to that number @ 7+ ozs we are now @ over 31 ozs+1.5 ozs Doctor Optic MRDS+TVNC Mount @ another few ozs. we are pushing somewhere North of 34 ozs. combined weight.
http://www.militarywarfighter.com/Leupold_110121_p/leupold-110121.htm

I shaved over 10 ozs. off for a very compact, light, bright, repeatable zero configuration that yields a lot of bang for buck regarding CQB to true intermediate ranges. For a 16"-18" 762x51 one would be hard pressed to improve upon in current offerings. SCAR 17, LMT L8, KAC EMC et al all work very well regarding efficacy.

Hope that’s crystal clear. Point being that La Rue may have been standard but that has been eclipsed for some time 5+ years now w/ lighter, robust repeatable zero mounts to shave weight. The people we train w/ are using this type of setup w/ repeated success for RECCE / Combat Tracker Units / Assault Scout “SUT” type of roles in theatre’s & venue’s OCONUS.

17

FWIW,
Anytime there is such a large discrepancy in things like this you have to scrutinize it all for the truth.
http://www.snipershide.com/2013/12/bigjimfish-review-of-the-u-s-optics-sr-8c-1-8x27mm-scope-with-c2-reticle/
“The SR-8C itself is unusual in appearance. It is, relatively speaking, long, at 12in; thin, at 30mm; and, not surprisingly, on the heavy side, at 34oz.”

Cui bono ?

18

I need to borrow your scales! Damn things make everything lighter…

19

Ya know, I read the review. Anybody w/ in the industry already knows USO are not known for the svelteness, but a 12 oz disparity ? I didn’t like the “C” model as it had some features for me that were not a fit. But does not preclude other’s from liking it or it being a good fit for their needs. So I went w/ the “S” model. I didn’t need daytime illum (& frankly feel daytime been overrated generally for most shooting scenario’s) Didn’t see the problems he was opining. Talked w/ FG @ SH & he said same things I saw & felt.
Had a few other SME’s I know look at it, shoot it (& they can all shoot real good) & none of them saw any of the aberrations / issues either. Then I re-read the review & looked at the weight. Took out the scale. Calibrated it several times for accuracy, took about 4 different optics & walla there is regarding the weight…like a beacon of truth…

20

Yeah, that is a huge disparity, and your remarks have actually helped a lot.

I’m 100% certain I’ll be going with the SR-8c now. I don’t believe much in the ways of all the optical criticisms in the BJF review, especially with your confirmations, and since it’s only 3 ounces heavier than the 1-4x on what will be a rifle more intended for longer side of 0-600m, I’ll enjoy the extra magnification much more than any of the other features from the 1-4x.

Thanks for your help. :slight_smile: