How to Choose a Rifle Scope
Recommended picks
Magnification: Match It to Your Distance
Magnification is the first number in any scope designation. A 3-9x scope dials from 3 power to 9 power; a fixed 4x stays at 4 power. For most hunting inside 300 yards, a 3-9x is the practical standard because it offers a wide field of view at low power and still resolves targets clearly at the top end. The MidTen 3-9x32-A, rated 4.4 stars across 857 reviews at $81.99, is a budget example of this range with a 41-foot field of view at 100 yards, which keeps close shots manageable. For longer-range work, a 2.5-10x like the MidTen 2.5-10x40-A ($45.99, 4.4 stars, 1,100 reviews) gives a similar floor with slightly more reach at the top. Going higher than 10x on a general-purpose scope adds weight and narrows the field of view without benefit unless shots routinely exceed 400 yards.
Objective Lens Diameter and Light Transmission
The number after the x is the objective lens diameter in millimeters. A 40mm objective is the most common, and it balances light-gathering with a tube diameter that clears most rifle stocks without requiring high rings. A 50mm objective gathers more light at dusk and dawn but demands taller rings, which can raise cheek weld issues. The MidTen 2.5-10x40-A runs a 40mm objective, the most common choice for this magnification class. Only step up to 50mm if low-light performance is a clear priority, such as for crepuscular game. Smaller objectives like 24mm or 32mm reduce weight and keep the scope more compact, which matters on lightweight platforms.
Reticle Types: What the Numbers and Patterns Mean
The reticle is the aiming pattern inside the scope. A simple crosshair or duplex is the fastest to acquire and works well for most hunters. A mil-dot or MOA grid adds holdover reference points for estimating range and compensating for wind or elevation at distance, which is why scopes like the MidTen 2.5-10x40-A include a Mil-Dot reticle at a budget price point. Illuminated reticles add a battery-powered glow for low-light conditions, seen across many Hawke and Firefield models. The Trijicon TA31RCO-A4CP at $1,339 and 4.8 stars uses a Chevron Ranging reticle that functions as both an aiming point and a ranging tool without requiring batteries. More elaborate reticles are only worth the cost if you will actively use the holdover marks.
Mount Compatibility: Picatinny, Weaver, Dovetail
A scope is only as stable as its mount. The three common rail systems are Picatinny (MIL-STD-1913), Weaver, and dovetail. Picatinny and Weaver rails look similar but differ in slot spacing; most Picatinny rings fit Weaver rails but not vice versa, so confirm before buying. Dovetail is common on air rifles and rimfire platforms. Many scopes ship with a mount included: the MidTen 3-9x32-A includes a Picatinny mount, while the Barska CO11538 (4.4 stars, 650 reviews, $65.01) uses an integral mount. If your rifle already has a rail, verify the ring height so the objective lens clears the barrel. Mismatched or loose rings cause point-of-impact shifts no amount of zeroing will fix.
Budget Brackets: What to Expect at Each Price
Under $100 buys a functional scope with aluminum construction and basic coated optics. The MidTen 2.5-10x40-A at $45.99 and the MidTen 3-9x32-A at $81.99 both hold over 800 reviews at 4.4 stars, which signals durable real-world performance at entry price. The $100 to $300 range steps up to better multi-coated glass, tighter turret adjustments, and more consistent magnification across the zoom range. From $300 to $700 you see premium coatings, parallax adjustment, and hardened construction from brands like Hawke. Above $1,000 you reach the Trijicon tier where the reticle itself is an illuminated precision tool, the housing is aircraft-grade aluminum, and the glass is produced to tighter tolerances. Budget should follow intended use, not the other way around.
Parallax, Turrets, and Secondary Features
Parallax error occurs when the target image and reticle are not on the same focal plane, causing the point of aim to shift as your eye moves. Most scopes factory-set parallax at 100 yards, which is adequate for under 300-yard use. Scopes intended for longer range often include a side-focus or adjustable objective knob to correct parallax at varying distances. Turrets are the knobs that adjust elevation and windage; capped turrets protect settings from accidental movement, while exposed tactical turrets allow fast field adjustments. Illuminated reticles add a red or green glow useful in dawn and dusk conditions but require a battery and add a small amount of weight. Only pay for these features if they match your actual application.
Common mistakes to avoid
- Buying higher magnification than the shooting distance requires, which shrinks field of view and makes tracking moving targets harder.
- Ignoring mount compatibility and discovering the rings or rail type do not match the rifle after the scope arrives.
- Choosing a 50mm objective without accounting for ring height, which forces a cheek weld that does not match the stock.
- Selecting an elaborate mil-dot or MOA reticle without learning how to use the holdover marks, leaving the extra lines as visual noise.
- Zeroing at only one distance and assuming the scope holds zero under recoil, without verifying after 20 to 30 rounds.
- Overlooking eye relief, particularly on high-recoil platforms, where too little distance between eye and ocular lens causes injury.
Frequently asked questions
What magnification do I need for deer hunting inside 200 yards?
A 3-9x is the standard choice and has been for decades. The low end gives a wide field of view for close brush shots and the top end resolves a deer clearly at 200 yards without over-magnifying. The MidTen 3-9x32-A with a 41-foot field of view at 100 yards is one example of this format at an accessible price.
What does the objective lens size actually change?
A larger objective lens diameter gathers more light, which helps at dusk or dawn. The tradeoff is a taller, heavier scope that requires higher rings and can raise cheek weld off the stock. For most daytime use, a 40mm objective is the practical sweet spot. Only step to 50mm if low-light hunting is a genuine priority.
Is a mil-dot reticle better than a simple crosshair?
It depends entirely on how you shoot. A mil-dot or MOA grid lets you hold over for wind and elevation without adjusting turrets, which is useful at longer distances. For hunting at moderate ranges, the extra marks add complexity without benefit. A simple duplex or crosshair is faster to acquire and harder to misread under pressure.
How much should I spend on a rifle scope?
Spend enough that the scope does not become the weak link in your accuracy. Under $100 works for casual range use and small-game hunting where optic quality is secondary. From $150 to $400 covers most serious hunting needs with noticeably better glass and turrets. Premium tactical or precision long-range use justifies $600 and above, where you're paying for tighter manufacturing tolerances and reticle precision.
What is eye relief and why does it matter?
Eye relief is the distance your eye must be from the ocular lens to see the full image. On most rifle scopes it runs from 3 to 4 inches. Too little eye relief on a high-recoil platform means the scope travels back into your brow. Always confirm the eye relief spec before mounting, especially on magnum or hard-kicking calibers.