Sig Tango-MSR 3-18x50 Review

A first-focal-plane 3-18x with a locking zero-stop dial is a lot of scope to put on a modest budget. The question is whether the turrets do what the dial says, and you can check that yourself.

The only question that matters on a budget precision scope

Budget optics rarely fail at being bright enough. The feature that separates a scope you can dial from a scope you hope about is tracking: when the turret says you moved the impact a certain amount, does the bullet agree? The Sig Tango-MSR 3-18x50 puts a first focal plane reticle, a 34 mm tube and a locking zero-stop elevation dial into a price class where shooters often hope for that and hesitate to trust it.

This review is built from Sig's high-magnification owner's manual and the Ammunition Depot listing. We have not shot this scope, so we will not tell you how the dial feels or how the glass compares to something else. What we can do is tell you what is documented, what is not, and how to check the part that matters yourself. If you are choosing between scopes, MatchGrade's Tango-MSR versus Burris XTR Pro versus Trijicon Tenmile comparison is the cross-brand read.

What the manual and listing document

Sig's manual for the Tango high-magnification line, which covers 3-18X and 5-30X models along with 2-12X, states several facts that apply to this scope:

• Focal plane: all models are first focal plane.
• Tube: 34 mm main tube.
• Reticles: MRAD Milling 2.0 or MOA Milling 2.0, both illuminated.
• Elevation turret: locking or non-locking depending on the model; locking dials have a zero stop reset with three set screws. The value of each click is marked on the dial.
• Windage: a dial with a removable cap.
• Parallax: adjusted with a side focus knob, then the diopter, and the manual says to readjust whenever target distance changes.
• Illumination: brightness set with a ring that alternates numbered on positions with off positions; powered by a CR2032, with the battery cap torqued to 10 inch-pounds.
• Eye relief: about four inches as a rule of thumb, set so that no shadow appears in the field of view.

The Ammunition Depot listing describes this model as 3-18x50, FFP, with an illuminated MRAD Milling 2.0 reticle, locking zero-stop elevation dials, an included ALPHA-MSR mount and flip-back lens caps. It does not give weight, length, click value or waterproof rating. The manual does not either, so for those figures check Sig's product page for the exact model number.

Why FFP matters for a dial-and-hold scope

In a first focal plane scope, the reticle sits in front of the magnification system. Leupold's glossary says such reticles scale with the image as you change power. For you, this means that mil or MOA subtensions are correct at 3x, 10x or 18x, so you can hold or range at any power. That is the main reason precision shooters like FFP, and it is why a scope in this class is interesting for learning to read wind and hold for drop.

The trade-off is that the reticle looks very fine at 3x and fills the view at 18x. Illumination helps at the low end. If you mostly shoot a rifle at moderate distances in the field, it is worth asking whether you need the 18x or whether a simpler scope would do. Our rifle scope and LPVO guide explains the focal plane choice.

Match the units, too. MRAD and MOA are different systems, and mixing a mil reticle with MOA turrets doubles your arithmetic. If you are not sure which suits you, MatchGrade's MOA versus MIL explainer covers it.

A box test you can run yourself

A box test is the standard way to check tracking. You need a rifle you can shoot consistently, a stable rest, a target with a clear vertical and horizontal reference, and a safe backstop. The goal is to compare what the dials say with where the bullets go.

1. Zero and confirm. Zero the rifle at a convenient distance and fire a small group.
2. Dial up. Dial a known elevation correction, fire a group, and mark it.
3. Dial across. Dial a known windage correction, fire a group, and mark it.
4. Dial down. Return elevation to the zero setting, fire a group, and mark it.
5. Dial back. Return windage to zero and fire a final group. It should land back on the original group.
6. Measure. Compare the measured distances to what you dialed. At 100 yards, one milliradian is about 3.6 inches and one MOA is about 1.05 inches.

If the final group does not return to the first, the scope may not be returning to zero. If the box is not square or the measured travel does not match the dial, the scope may not track to the dial's claim. Neither result is a death sentence. It tells you how far to trust the dials, and it may suggest a mounting problem, which is worth ruling out first. Our zeroing guide covers rail and ring checks.

Use fresh ammunition from one lot where you can, shoot from the same position each time, and log the data. Variation in the rifle or ammunition can look like scope error, so repeat the box if the result surprises you.

Mounting and the zero stop

The scope's 34 mm tube needs 34 mm rings or the included mount. The manual says to use an inch-pound torque wrench and the manufacturer's recommended torque, without giving a figure. That means you need the specification from the ring or mount maker, not a number from a forum. Over-tightened rings can pinch a tube and cause problems, so use the maker's specification and a proper torque tool. For the same reason, do not use impact tools.

Set the zero stop after you have a confirmed zero: with the dial at your zero, loosen the three set screws, reset the dial so it sits at zero against the stop, and tighten. Then verify by dialing up and back down. The manual describes the three-screw procedure but gives no revolution count, so check the dial itself to see how many turns you have.

Who it suits, and who should step up

• Suits: a hunter who wants reach and a locking dial; a newer shooter learning to dial and hold; the owner of a second rifle who does not want to swap a premium scope between guns.
• Step up if: you compete, shoot beyond a few hundred yards regularly, or need glass and tracking that have a long, documented history.
• Skip if: you will mostly shoot inside 300 yards at moderate magnification; a lighter, simpler scope may fit better. Our hunting scope guide covers that case.

Check current price and availability for the Sig Tango-MSR 3-18x50, and confirm weight, click value and reticle version on Sig's page for your model. To compare magnified optics side by side, browse the scope category at Ammunition Depot.

Final checks before you commit

If you buy it, run the box test early and keep the data. If it tracks, you have a capable training tool. If it does not, you will know before it matters. Either way, you will understand your rifle better than you did before the box test, which is worth more than a brochure.

Editorial note: This is an independent editorial overview built from manufacturer specifications and publicly available information. We have not performed hands-on testing of the products discussed, and nothing here is a performance guarantee. Verify specifications, compatibility and legality for your own situation.

Affiliate disclosure: Some links on this page are affiliate links to Ammunition Depot. We may earn a commission if you buy through them, at no extra cost to you. Our editorial choices are not influenced by commissions. Check current price, stock and specifications directly with the retailer.