Rifle Scopes: The Complete Guide
It's first light on a Texas ranch, the deer is a little over 200 yards out, and the difference between a clean shot and a clean miss is whether your reticle, your turrets, and your zero all agree. That agreement starts with picking the right scope — and the string of numbers on the box is the key to it. Choosing a rifle scope comes down to five decisions: magnification range, focal plane, turret and reticle units, parallax and eye relief, and glass quality for your budget. Get those right for the distance you actually shoot, and the scope disappears, leaving just you and the target.
Key takeaways
- A scope's name reads magnification × objective: a 2.5–20×50 zooms from 2.5 to 20 power on a 50 mm objective lens.
- First focal plane (FFP) reticles scale with magnification so holdovers stay true at any power; Accufire's EVRO-12 and ATRO-20 are both FFP.
- Match your turret units to your reticle — MOA with MOA, or MRAD with MRAD. The Accufire scopes use 0.1 mrad clicks with mil reticles.
- Set parallax with the side-focus dial and set eye relief at mounting; both Accufire scopes adjust parallax from 50 yards to infinity and give about 3.22–3.5 inches of eye relief.
- A capable FFP precision scope starts at $479.00 (EVRO-12); the advanced ATRO-20 is $649.25.
How to read a rifle scope's name
Every scope's name encodes its core configuration. In 2.5–20×50, the "2.5–20×" is the magnification range — it zooms from 2.5 power to 20 power — and "50" is the objective lens diameter in millimeters. A larger objective gathers more light for a brighter image at dawn and dusk, but it adds weight and forces taller rings. The tube diameter (commonly 1 inch, 30 mm, or 34 mm) is a separate spec that affects elevation travel and ring choice; Accufire's EVRO-12 and ATRO-20 use a 30 mm tube. For a full walk-through, see how to read rifle scope numbers.
Magnification: how much you actually need
More magnification is not automatically better — it narrows your field of view, magnifies wobble, and dims the image. Match it to distance and target size. For brush and timber, 1–6 power is plenty; for general field and hunting use, a 3–9 or a versatile 2.5–20 covers nearly everything; for deliberate long-range work, a higher top end earns its keep. A low-power variable optic (LPVO) trades distance reach for blazing speed up close — our LPVO guide covers that category. Accufire's scopes are 2.5–20×50, an 8× zoom range that spans close work to distance on one optic.
First vs second focal plane
This is the choice most new buyers overlook. In a first focal plane (FFP) scope the reticle grows and shrinks with magnification, so its holdover and ranging marks stay accurate at every power — the reason precision and long-range shooters favor it. In a second focal plane (SFP) scope the reticle stays the same apparent size, and its subtensions are correct at only one magnification (usually the maximum); SFP keeps a fine reticle visible at low power and is common on hunting and rimfire scopes. Accufire builds both the EVRO-12 and ATRO-20 as FFP optics. Our deep dive on FFP vs SFP lays out which suits your shooting.
Turrets and reticle: MOA vs MRAD
Turrets move your point of impact in clicks, measured in either MOA (minute of angle) or MRAD (milliradian). Neither is more accurate — they're two units for the same job. MOA clicks are typically finer per click and suit shooters who think in inches and yards; MRAD is base-ten and pairs cleanly with metric ranging. The rule that matters: your turret unit and your reticle unit must match, so a correction you see in the reticle dials straight onto the turret. The Accufire EVRO-12 and ATRO-20 use 0.1 mrad clicks with matching mil reticles. If you're undecided, read MOA vs MRAD and our guide to reticle types.
Parallax and eye relief
Parallax is the apparent shift of the reticle against the target when your eye moves off the scope's center axis; at higher magnification it can throw shots if uncorrected. An adjustable parallax control — usually a side-focus dial — brings the target and reticle into the same focal plane. Both Accufire scopes adjust from 50 yards to infinity. Parallax, explained covers how to set it.
Eye relief is the distance from the ocular lens to your eye where you see the full, edge-to-edge image. Too little on a hard-recoiling rifle invites scope bite; too much and the image vignettes. The EVRO-12 and ATRO-20 list roughly 3.22–3.5 inches across their magnification range — set it when you mount the scope, in your natural shooting position. See eye relief, explained.
How to choose: match the scope to the job
There's no single "best" scope — only the right one for your distance, rifle, and budget. Competitors cover every tier: Vortex (Strike Eagle, Viper PST), Leupold (VX, Mark series), Athlon (Argos, Ares), Primary Arms (SLx, GLx), and Nightforce at the premium end. Accufire's position is a manufactured-not-white-labeled FFP optic at an accessible price. Here's how its two scopes compare:
| Model | Magnification × objective | Focal plane | Adjustment | Price | Best for |
|---|---|---|---|---|---|
| Accufire EVRO-12 | 2.5–20×50 | First focal plane | 0.1 mrad clicks, locking turrets | $479.00 | Versatile precision, value |
| Accufire ATRO-20 | 2.5–20×50 | First focal plane | 0.1 mrad clicks | $649.25 | Precision marksmanship |
Both share the same optical formula; the EVRO-12 is the essential, value-tier entry, while the ATRO-20 is the advanced build for shooters who want the higher-tier option. For a fuller head-to-head with use cases, see our rifle scope buyer's guide.
Mounting, leveling, and zeroing basics
A great scope mounted badly shoots badly. Use rings of the correct height and tube diameter, level the reticle to the rifle, and torque the ring and base screws to the values in the manufacturer's instructions — over-torquing can crush a tube, under-torquing lets it shift. Set eye relief, then bore-sight and zero at a known distance (100 yards is the common rifle zero; confirm for your load). Learn the click math first with how to adjust a rifle scope, then walk the full process in how to zero a rifle scope. Keep every step within the firearm manufacturer's guidance and your local regulations.
Honest limitations
No scope does everything. High magnification narrows your field of view and amplifies every heartbeat and breath, which is why fast, close shooting still favors a red dot or LPVO. A big objective brightens the image but raises your mounting height and weight. FFP reticles can look thin and hard to see at the lowest power — the trade for accurate holdovers at every magnification. And glass quality scales with price: an honest sub-$500 scope is a strong value, not a $2,000 alpha optic, and we'd rather tell you that than pretend otherwise. Buy for the distance you actually shoot, not the distance you imagine.
Ready to choose a rifle scope? Accufire builds its EVRO-12 and ATRO-20 in-house — first focal plane, 30 mm tube, 0.1 mrad turrets — at prices that leave room in the budget for glass-time — shop the Accufire rifle scope collection.
Accufire EVRO-12 Essential Variable Rifle Scope — $479.00. A first focal plane 2.5–20×50 on a 30 mm tube with 0.1 mrad clicks, locking turrets, and side parallax from 50 yards to infinity — a versatile precision starting point. View the EVRO-12.
Frequently asked questions
What do the numbers on a rifle scope mean?
A scope's name lists magnification and objective lens size. In 2.5-20x50, the 2.5-20x is the magnification range, from 2.5 power to 20 power, and 50 is the objective lens diameter in millimeters. A larger objective gathers more light but adds size and weight.
What is the difference between first and second focal plane?
In a first focal plane scope the reticle grows and shrinks with magnification, so the holdover and ranging marks stay accurate at every power. In a second focal plane scope the reticle stays the same apparent size, and its subtensions are correct at only one magnification, usually the highest. Accufire's EVRO-12 and ATRO-20 are both first focal plane.
Is MOA or MRAD better for a rifle scope?
Neither is more accurate; they are just two units for the same adjustments. MOA moves in finer increments per click and suits shooters who think in inches and yards, while MRAD is base-ten and pairs cleanly with metric ranging. The important thing is that your turrets and reticle use the same unit. Accufire's EVRO-12 and ATRO-20 use 0.1 mrad clicks with matching mil reticles.
What magnification do I need on a rifle scope?
It depends on distance and target size. For brush and timber hunting, 1 to 6 power is plenty; for general field use, a 3 to 9 or a 2.5 to 20 variable covers most shots; for deliberate long-range work, higher top-end magnification helps. A versatile 2.5-20x like the Accufire scopes spans close work to distance on one optic.
How much eye relief does a rifle scope need?
Enough that the full sight picture is visible without the scope sitting too close to your eye, which matters most on hard-recoiling rifles. Many variable scopes offer roughly 3.5 to 4 inches; the Accufire EVRO-12 and ATRO-20 list about 3.22 to 3.5 inches across their magnification range. Set eye relief when you mount the scope so you get a full, edge-to-edge image in your normal shooting position.
Start with the distance you shoot, read the numbers, match your turrets to your reticle, and mount it level — that's the whole craft. Go deeper with our companion guides on reading scope numbers, FFP vs SFP, and the best rifle scope for your use case.