Riflescopes Explained for Success Afield

This guide is here to cut through the noise. By the time you’re done reading, you’ll not only understand key scope terminology but also how to apply this knowledge to your shooting. Whether you’re hunting, competing, or setting up a defensive rifle, you’ll be the smartest person in the room when the topic of optics comes up.

Scope Nomenclature

Every riflescope is labeled with a series of numbers and letters that describe its magnification and objective lens size. If you’ve ever seen something like “3-9×40” or “1-6×24” and weren’t exactly sure what it meant, let’s break it down:

• Magnification (3-9x, 1-6x, etc.) – This tells you the zoom range of the scope. A 3-9x scope means you can adjust between 3x and 9x magnification. A fixed-power scope, like a 10×42, is always at 10x magnification.
• Objective Lens Diameter (40mm, 24mm, etc.) – The second number (like 40 in 3-9×40) refers to the diameter of the objective lens in millimeters. A larger lens allows more light in, which improves brightness but can also add weight and bulk.

Field of View (FOV) and How It Can Change

Field of View (FOV) is how much area you can see through the scope at a given distance. This is crucial because:

• Higher magnification = Smaller field of view.
• Lower magnification = Wider field of view.

For example, at 3x magnification, your field of view might be 35-feet wide at 100 yards. But at 9x magnification, you might only see 12-feet at the same distance.

This is why hunters and tactical shooters often use lower magnifications in dense environments—having a wider view helps them track movement and engage threats faster.

First Focal Plane (FFP) vs. Second Focal Plane (SFP) Scopes

One of the biggest decisions when selecting a riflescope is FFP vs. SFP, and it all comes down to how the reticle behaves when you zoom in and out.

• First Focal Plane (FFP): The reticle scales with magnification, meaning the holdovers stay consistent at all power levels. This is ideal for long-range shooting where you’ll be making adjustments at different zoom levels.
• Second Focal Plane (SFP): The reticle stays the same size regardless of magnification. However, holdovers are only accurate at one specific power setting (usually the highest magnification).

Which One Should You Choose?

• For precision rifle shooting: FFP is the way to go. The ability to use holdovers at any magnification is a huge advantage.
• For hunting or general use: SFP works great. Most hunters use scopes at a fixed magnification and don’t need to worry about reticle scaling.

LPVOs: The Best of Both Worlds?

Low-Powered Variable Optics (LPVOs) have exploded in popularity, especially on AR-15s and defensive rifles. These optics offer true 1x magnification for quick target acquisition but can zoom up to 4x, 6x, or even 10x for longer-range shots.

Why Use an LPVO?

• Versatility: You get the benefits of a red dot and a magnified optic in one package.
• Faster Target Engagement: At 1x, it functions like a reflex sight.
• Precision at Distance: At 6x or higher, you can make shots out to several hundred yards.

If your rifle needs to cover CQB (close-quarters battle) to mid-range engagements, an LPVO is a great choice. But with their smaller Objective Lenses you may need more light getting through the glass shooting at distance. LPVO’s are versatile but they are specialized for any single task.

Mils vs. MOA: What’s the Difference?

One of the most debated topics in the precision shooting world is Mils vs. MOA (Minute of Angle). Let’s break it down in simple terms:

• MOA (Minute of Angle): 1 MOA is roughly 1 inch at 100 yards. If a scope adjusts in ¼-MOA clicks, that means each click moves the reticle ¼ inch at 100 yards.
• Mils (Milliradians): 1 Mil equals 3.6 inches at 100 yards. If a scope adjusts in 0.1-Mil clicks, each click moves the reticle 0.36 inches at 100 yards.

Which One Should You Choose?

• MOA is great for traditional hunting and target shooting because most shooters think in inches.
• Mils are often preferred for tactical and long-range precision shooting because they use a more universal system based on angular measurements.

At the end of the day, both work well—just pick one and learn it inside and out.

Bubble Levels: A Must for Long-Range Shooting

If you’re shooting at extended distances, having a bubble level on your scope is essential. Here’s why:

• Canting the rifle (tilting it slightly) can dramatically shift the point of impact at long range.
• Even a few degrees of tilt can cause a bullet to miss a target by inches or feet at 800+ yards.
• A bubble level mounted on your scope ensures your rifle stays level, maximizing accuracy.

For hunters, PRS competitors, and long-range shooters, a bubble level is a simple yet critical tool.

Choosing the Right Scope for Your Needs

So how do you decide which scope is right for you? Let’s break it down into common use cases:

• Hunting: Lightweight, simple SFP scopes with moderate magnification (like a 3-9×40 or 4-12×50) work well.
• Tactical & Home Defense: LPVOs (like a 1-6x or 1-8x) offer fast target acquisition while maintaining precision.
• Precision Rifle Shooting: High-powered FFP scopes with exposed turrets, reticle holdovers, and adjustable parallax (like a 5-25×56) are ideal.
• General Purpose / All-Around: A solid 2.5-10x or 4-16x scope provides a mix of hunting and target shooting capability.

Parallax Adjustment – What It Is and Why It Matters

Parallax is one of the most misunderstood concepts in rifle optics, yet it plays a crucial role in precision shooting. In simple terms, parallax occurs when the reticle appears to shift against the target when the shooter moves their eye behind the scope. This can lead to inconsistent aiming and missed shots, especially at longer distances.

Many high-quality scopes come with a parallax adjustment knob (often labeled as “side focus” or adjustable objective). This knob allows you to correct parallax at different ranges, ensuring that your reticle and target are on the same focal plane.

How to Check and Adjust for Parallax:

1. Set your rifle on a steady rest and focus on the reticle.
2. Move your eye slightly left and right behind the optic without moving the rifle.
3. If the reticle shifts over the target, parallax is present, and you need to adjust.
4. Use the parallax adjustment knob until the reticle stays perfectly still on target.

For hunters and LPVO users, parallax is less of a concern since most shots occur at moderate distances. However, for long-range precision shooters, correcting parallax is critical for maintaining pinpoint accuracy.