Sightron SIIB Big Sky 3-9x42mm Riflescope

By Chuck Hawks

Sightron SIIB 3-9x42
Illustration courtesy of Sightron

The Sightron SIIB "Big Sky" riflescope line represents a huge addition to the Sightron line. These are new and upgraded scopes that have replaced most (but not all as of this writing) of the previous SII line. The SIIB scopes include target/competition, fixed power, variable power and compact riflescopes.

The outstanding SIII scopes remain Sightron's top of the line and highest priced offerings. The new SIIB Big Sky line lies in-between the SIII and the standard SII scopes, taking on such well respected riflescopes as the Leupold VX-II/FX-II, Burris Signature Select and Weaver Grand Slam. Such price based comparisons are approximate, of course, but intended to give you an idea of where the new SIIB line fits in the world of riflescopes.

All SIIB models feature Sightron's ExacTrack windage and elevation system for accurate and repeatable adjustments. The optics are fully multi-coated with enhanced ZACT-7 Revcoat lens coatings that reflect green, blue, purple and magenta colors depending on the angle of the light.

Our Big Sky came as boxed a complete package with a Sightron scope wrap, instruction booklet, warranty cards, a lens cleaning cloth and see through lens caps with double retaining straps that properly fit the scope's objective and ocular bells. And, of course, there is Sightron's no hassle Lifetime Replacement Warranty. Sightron has earned an enviable reputation for standing behind their products.

Here are the basic specifications of the Sightron SIIB 3-9x42mm Big Sky riflescope.

  • Item Number: SIIB3942
  • Finish: Satin black
  • Magnification: 3-9X
  • Lens Coatings: Fully multicoated (Zact-7TM 7-Layer)
  • Field of View at 100 Yards: 31.9' -11.3"
  • Eye Relief: 3.9-4.1"
  • Reticle Type: Duplex
  • Parallax focus: 100 yards
  • Adjustment Click Value: 1/4 MOA
  • Windage and Elevation Adjustment Range: 70 MOA
  • Objective Lens Diameter: 42mm
  • Main Tube Diameter: 1" (25.4mm)
  • Overall Length: 12.64"
  • Weight: 13.4 ounces
  • Accessories: Lens covers, Sightron cloth wrap, lens cleaning cloth
  • Country of Origin: Japan
  • 2007 discount retail price: $354 (MidwayUSA and SWFA)

Physically, the Big Sky 3-9x42 is a good looking scope. It has a deep, matte black external finish with a modest bronze colored "S" (for Sightron) on the adjustment turret. The ribbed aluminum zoom ring has a large tactile lump and is marked with bronze numbers from 3 to 9 representing the magnification setting and fine letters on a ring at the front of the ocular, also in bronze color, repeat "Sightron SII Big Sky 3-9x42." All of this is done in a very restrained fashion, unlike some scopes that we have reviewed recently. The bronze markings look good and are subtle, but are a little harder to read in dim light than the usual gold or white markings. The Sightron Big Sky 3-9x42 should complement the appearance of practically any high quality hunting rifle.

The adjustment turret caps are aluminum, not plastic. Underneath are fingertip windage and elevation adjustment dials that are easy to grasp and click in 1/4 MOA increments in a positive manner. Once the scope/rifle is sighted-in, just lift the adjustment dial to reset it to a zero setting. The top of the dial is clearly marked to indicate 1 click = 1/4", Pull Up to Reset, and the direction of rotation.

Focus to the user's eye is achieved by loosening a heavily knurled lock ring and turning the ocular bell on fine threads in the traditional fashion. Once the focus is correct, the lock ring is tightened to preserve the setting.

All adjustments, including focus, zoom and the windage/elevation adjustments turn smoothly and with about the right amount of resistance. You don't have to fight them, but you are unlikely to change them accidentally.

Looking through the SIIB 3-9x42 demonstrates that its optics are superior. The view of the target is sharp and contrasty. Flare is well suppressed and sharpness from center to edge is very good. Optical aberrations are very well corrected, even at the edge of the field of view.

The Sightron Duplex reticle is properly proportioned for a big game hunting scope and entirely adequate for a .17 HMR small game hunting rifle as well. Its fine center crosshairs allow precise aiming and its heavier outer posts are easy to see in dim light. This is one of the better Duplex reticles on the market.

The spacing between the adjustment turret and the ocular and objective bells is adequate in both directions, providing good mounting latitude. This is an area that some scope manufacturers disregard and buyers may not notice--until they try to mount a poorly designed scope on their rifle. Sightron has always taken mounting into consideration in the design of their riflescopes and most models can be mounted on most rifles without resorting to expensive (and sometimes hard to get) offset rings and/or bases.

A nice scope deserves an equally nice rifle (and vice versa), so I mounted the Sightron Big Sky on a new Weatherby XXII .17 HMR rifle consigned to Guns and Shooting Online for review, even though the SIIB is intended for use on centerfire rifles and the Mark XXII is a rimfire rifle with a consequently short receiver. To do so I used the 3/8" (11mm) dovetail grooves provided on the top of the Weatherby's receiver and Simmons tip-off mounting rings that I happened to have on hand. (There is a review of the Weatherby XXII rifle on the Product Review Page.)

I got the Sightron/Weatherby combination to the Isaac Walton gun range south of Eugene, Oregon--our usual testing facility--as quickly as possible. Okay, I was anxious to do a little shooting with this sharp looking rifle and scope. Guns and Shooting Online's Rocky Hays and Jim Fleck, along with our mutual friend Jeff Johnson, helped with the shooting and the evaluation.

As usual, I first adjusted the scope to put bullets in the "X" ring of a bull's eye target at 25 yards before moving back to do some serious shooting at 100 yards. In the case of our Sightron SIIB equipped Weatherby, zeroing at 25 yards took exactly 5 shots, a tribute to the precision of the Sightron Exac-Trac adjustment system. That accomplished, we moved to 100 yard targets, because sighting-in at 25 yards is not the same as sighting-in at 100 yards.

The first group at 100 yards centered about 3.25" high and 1.5" to the right. I dialed in 13 clicks of negative elevation and 6 clicks of left windage. The next group was in line with the bull's eye, but about an inch low. (Maybe I mis-counted my elevation clicks.) I added 4 clicks of "up" elevation and that put the next group into the bulls'eye. So much for sighting-in.

To verify the repeatability of the scope's adjustments, after the rifle was zeroed dead on at 100 yards I lifted the adjustment knobs and reset the dials without changing the point of impact. I then used the windage and elevation knobs to intentionally shift the point of impact 2" (8 clicks) to the right and 2" (8 clicks) up. Returning the adjustments to their original ("0") settings also returned the point of bullet impact to the center of the bull's eye. This scope's Exac=Trac adjustments are more than sufficiently accurate for a hunting rifle.

I can't tell you how many times I've heard a shooter exclaim, "That scope costs as much as the rifle!" Maybe so, but it is hard to hit what you can't clearly see and the fire control system (the scope in this case) is every bit as important as the launching device (rifle) in any ballistic missile system. Any Army or Navy gunnery officer can confirm that.

Shooters and hunters who invest in Sightron Big Sky riflescopes instead of less capable economy models will reap the benefits of their decisions every time they shoot their rifles. You can't have too good a fire control system on any rifle.

After this review was completed I earmarked the scope reviewed here for installation on my Remington Model 798 rifle. This classic Mauser .30-06 is another rifle on which the Sightron Big Sky looks right at home. As they say, class will out.

All of the Guns and Shooting Online reviewers left the rifle range very impressed by the Sightron SIIB Big Sky 3-9x42 riflescope. It is hard to find anything to criticize about this scope, but it is easy to praise. It looks great, works great, is built to last and is backed by a reputable manufacturer with a reputation for excellent customer service. What more could a riflescope buyer possibly need?

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Copyright 2007, 2012 by Chuck Hawks. All rights reserved.