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Old March 22, 2010, 09:57 AM   #1
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Range Report - NcStar Mark III Quick Release Tactical Rifle Scope

NCStar, STR3942G, 3-9x42 Illuminated Red/Green Rangefinder Scope (

Sometimes you want a scope in a hurry and when you do sometimes you take a chance.

I wanted some 100 yard glass for my new AR rifle and I was feeling impatient but funds were short so there wasn’t going to be any Leupold (let alone a Vortex or something like an ACOG) so when I saw the NcStar Mark III Quick Release Tactical Rifle Scope sitting on a local shelf I was intrigued. A glance through the eyepiece and the sight picture appeared reasonably clear and bright so I decided to “go for it”.

The Specifications:
Externally the STR3942G is a fairly compact “ACOG-esque” shape with the following features.
  • Open Target Turrets
  • Fully Multi Coated Lenses
  • Built in sunshade
  • Quick focus eyepiece
  • Bullet drop compensator calibrated for the .223 cartridge with a 55 grain bullet
  • illuminated Red/ Green Reticles (powered by a single CR2032 battery)
  • Multiple brightness setting (3 Red, 3 Green)
  • Integrated Quick Release weaver style/ picatinny mounting system
  • A 3x-9x magnification with a 42mm Objective lens

Additionally the scope is supposed to be nitrogen filled, waterproof, and have a fogproof coating.

There are three variations of this scope. The “STM” has a Mil-Dot Reticle, the “STP” has a P4 Sniper Reticle, and the “STR” has a Rangefinder Reticle. I have the “STR”.

Mounting and testing:

Attaching the scope to a picatinny rail was simplicity as the scope and mount are integral so there is no “leveling” or any other fussing about. The materials and construction feel solid and well assembled. Boresighting at maximum magnification was quick though when setting elevation I noticed an annoying tendency for the top turret’s “bullet drop compensator” (BDC) dial to turn along with the elevation adjustment dial. (The elevation adjustment is a dial, hidden under a cap, inside the BDC dial)

In order to avoid this unwanted motion I had to use two hands (one holding the compensator dial still while the other adjusted the elevation setting with a screwdriver). This was annoying for boresighting but much worse when I was actually zeroing the sight in later at the range and I finally had to enlist the aid of a second person (to hold the BDC dial and prevent it from turning as I braced the rifle and looked through the scope) to get the elevation dialed in. On the positive side, the detent clicks for both the Elevation adjustment and the BDC dial are very positive and clean.

Adjusting windage is just one knob so that was simple and fast but there were two issues to overcome. Firstly there was no “witness mark” dot or line to indicate what number the windage knob was dialed to and secondly (unlike the BDC/Elevation knobs) the “clicks” of the windage dial are just pure mush and it’s really hard to tell if you’ve done a full click, half a click, or more than one. I basically solved both issues by using a staking punch to make a small dimple and then indexing the lines on the windage dial via that dimple. Once I had windage “dialed in” I actually loosened the grub screw on the dial and aligned the dial’s “zero marking” with the dimple and then re-tightened the knob back in place.

In short, zeroing this scope wasn’t quite the straightforward “point and click” operation it should have been but it wasn’t the kind of nightmare I’ve had with some scopes.

Once zeroed I shot three groups from a bench and was very satisfied with the results. Next I ran the BDC and Windage dials to various settings then back to their “0” position. I also ran the magnification dial back and forth to various positions. The scope held zero through all of this (though the mushy windage knob made returning to “0” setting a little challenging. I’m very glad I made that dimple "witness mark").

I did not test the accuracy of the 200 or 300 yard marks on the BDC dial because I didn’t have a range that went that far at the time.

I then removed the scope (all you have to do is flip a lever) and shook it vigorously and gave it a few gentle raps against a wooden table top, shook it some more, and re-attached it to the rifle. Zero was unaffected by this treatment.

Other items of note:
I found that I really liked the “Rangefinder” reticle setup though for 100+ yard shooting the center of the crosshairs is a little thick. I wish they had gone with a pinprick center dot or very fine center crosshairs.

I also discovered that the reticle illumination is VERY bright and there isn’t a whole lot of difference from the lowest to the highest setting (3 positions) . In dusky conditions the 42mm objective still collects enough light to be useful, but even the lowest green setting is kind of blinding. I’m actually looking forward to the batteries dying down a little bit so the illumination is dimmed somewhat <grin>. Speaking of battery life, I have no idea what it will be but the scope uses a common CR2032 battery and in daylight the crosshairs are completely usable with the illumination turned off.

The scope is surprisingly clear and bright for optics in this price range but it is a budget scope so let’s not even pretend it holds a candle to Nikon glass and if you push the upper limits of 9x and more than 150 yards things start to fuzz, but for an AR based “fun at the range” gun it’s more than adequate.

  • Sighting in is a pain because the BDC dial tends to turn with the elevation adjustment.
  • Windage dial is mushy and has no witness mark
  • Reticle crosshairs are a bit thick for >100 yard shots
  • Reticle illumination is actually TOO BRIGHT on the lowest setting
  • Clarity decreases at max magnification though it’s still very usable.
  • Inexpensive
  • Bright
  • Easily mounted, removed, remounted
  • Construction seems of good quality and feels solid
  • Looks “right” on an AR style gun (not too big, not too small)
  • Held zero even after being removed and tapped on a table top then re-attached.
  • Rangefinder reticle is just cool <grin>


In spite of the setup issues I’m finding that I actually like this scope. Should I get the wherewithal to buy something higher end I’m sure I’ll do so but for now it enables me to do some longer range shooting and enjoy the gun at a (comparatively) low price point.

Recommended…as long as you understand the limitations of a budget scope and don’t expect miracles.
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Old March 31, 2010, 01:34 PM   #2
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Ownership Update 3/31/2010

After being drenched in a torrential downpour the lowest "red" light setting started flickering a little bit. A finger tap or two and it was fine and there were no issues with any of the other "red" or "green" settings but it appears some water penetrated someplace in there and affected contact a little bit.

After a day the issue ceased (I'm guessing the water dried out).
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Old March 31, 2010, 03:52 PM   #3
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Location: Denver, CO
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I had the same scope on my AR...was decent. I also liked the rangefinder reticle. I also thought that even at lowest brightness settings, it was far too bright and washed out the picture downrange.

Only gripe was after a few hundred rounds, the screws holding it to the base loosened up and the scope wobbled.

I'd remove those and loctite them back in if I were you.

Ended up selling the scope to fund an EOTech a few months later.
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Old April 24, 2010, 01:30 PM   #4
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Ownership Update - 4/24/2010

I'm out of commission for shooting right now, but let a friend use the SR-556 for the day.

His groups started wandering and we could not get the scope to stay zeroed.

Close examination showed that the scope was just slightly loose on it's base. The NCStar is held onto the base with 3 hex-head screws, one of which is hidden by the "layered" assembly of the scope and base that goes like this...

====Base part 1 (riser)=====
====Base part 2 (clamp)====

Anyway, I disassembled the loose parts, degreased them, and then re-assembled with lock-tite. When I put the scope back together everything was solid and stable again and I didn't even have to re-zero the scope from it's "0" dial settings.

So if you have this type of scope and it seems to lose the ability to zero, check and see if it's actually tight between the scope and the layers of the base riser and base clamp. If it's not tight the culprit may be that hidden center screw has come loose not a failed scope.

Hopefully this image helps, I didn't have a camera handy while I had the scope apart.

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