How to Choose a Rifle Scope: Magnification, Reticle, MOA and Mounting

Choose a rifle scope by the shooting you actually do, not by the biggest number on the tube. For most Australian hunting a 3-9x40 or 2.5-10x42 in the second focal plane covers it. Match the reticle to the turret units, buy the best glass you can afford in that size, and spend properly on rings and mounting.

Magnum Sports — NSW Firearms Dealer Licence No. 413159984. Last reviewed: 28 September 2026.

Start with the job, not the specification

Almost every unhappy scope purchase we see across the counter comes from the same mistake: buying the magnification someone wanted rather than the magnification their shooting needs. A 6-24x50 on a scrub rifle is a liability. A fixed 4x on a benchrest gun is a handicap. Before anything else, answer three questions honestly.

• What distance do you actually shoot? Not your best day — your typical day. Most Australian hunting shots are taken well inside 200 metres.
• In what light? First and last light is when game moves, and it is where cheap glass falls apart.
• How much does the rifle get carried? Weight and bulk you carry all day are a real cost.

Everything below follows from those three answers.

Magnification: less than you think

Magnification narrows your field of view and magnifies your wobble along with the target. At 3x you can find an animal in thick country quickly; at 18x you are hunting for it through a straw while your heartbeat throws the reticle around.

Useful starting points for Australian conditions:

• Scrub, close country, pigs and goats inside 150 m — 1-6x, 2-7x or 3-9x. Speed of acquisition beats resolution here.
• General hunting, deer and foxes to 300 m — 3-9x40 or 2.5-10x42. This is the most useful all-round bracket ever made and there is a reason it has outlived every trend.
• Open country, varmints, longer work — 4-16x or 5-25x, where you have time, a rest and a known distance.
• Target and benchrest — higher again, with the parallax adjustment and turret travel to match.

A useful discipline: most hunters who buy a 4-16x leave it on 6x or 8x for ninety per cent of the time it is on the rifle. If that sounds like you, buy the lighter scope and spend the difference on glass.

Objective size, exit pupil and the low-light myth

A bigger objective lens gathers more light, but only up to the point your eye can use it. Divide objective diameter by magnification and you get the exit pupil in millimetres — the disc of light leaving the eyepiece. A young adult eye dilates to roughly 7 mm in darkness, and less as you age.

So a 3-9x40 at 9x gives a 4.4 mm exit pupil, which is comfortably usable at dusk. The same scope wound back to 4x gives 10 mm, more than your eye can accept — the extra is wasted. Meanwhile a 6-24x50 at 24x gives just 2.1 mm, which is why high magnification feels dark at last light no matter how big the front lens is.

The practical lesson is that winding the magnification down does more for your low-light performance than buying a bigger objective. A 50 mm or 56 mm front end also forces higher rings, which raises your cheek weld and makes a consistent head position harder. Take the bigger objective when you genuinely need it, not by default.

Lens coatings matter more than diameter in this conversation. Fully multi-coated glass transmits far more light than a single-coated lens of the same size, which is most of what you are paying for as you move up a range. Our explainer on optical terminology unpacks what the marketing letters mean.

First or second focal plane

In a second focal plane (SFP) scope the reticle stays the same visual size as you change magnification. The subtensions — the spacing of the hash marks — are only correct at one stated power, usually the top one. In a first focal plane (FFP) scope the reticle grows and shrinks with the image, so the subtensions are correct at every magnification.

The trade-off is legibility. An FFP reticle that is usable at 20x can be a hairline at 4x, and one that is bold at 4x can obscure a small target at 20x. SFP reticles stay crisp everywhere.

For most hunters, SFP is the right answer. You are holding centre or using a simple holdover you have practised, at a distance you can estimate. FFP earns its place when you range, dial or hold precisely at varying magnifications — competition, long-range work, or serious pest control at unknown distances.

MOA or MIL: pick one and stay in it

These are just two units for angle, and neither is better.

• MOA — one minute of angle is about 29 mm at 100 m (close enough to call it an inch at 100 yards). Most scopes adjust in quarter-MOA clicks, so one click moves roughly 7 mm at 100 m.
• MIL — one milliradian is 100 mm at 100 m, exactly. Most MIL scopes adjust in 0.1 MIL clicks, so one click moves 10 mm at 100 m. The arithmetic is cleaner because it is decimal.

The rule that actually matters: your reticle and your turrets must use the same unit. A MIL reticle with MOA turrets means every correction needs a conversion, in the field, under time pressure, and it is the most common self-inflicted wound in this whole subject. Check the specification before you buy, not after.

If you are starting fresh and expect to dial or hold with the reticle, MIL is easier to do mental arithmetic in. If everyone at your club talks in inches and MOA, take MOA and fit in.

Reticles

Simpler is better than busier for most shooting.

• Duplex or plex — heavy outer posts drawing the eye to a fine centre. Fast, uncluttered, ideal for hunting inside 300 m.
• Illuminated centre — worth real money at dawn and dusk against dark hide. Make sure the lowest brightness setting is genuinely low; many are not.
• Hash or tree reticles — calibrated holdover and wind marks. Excellent if you have learned them, clutter if you have not.
• Red dots and reflex sights — no magnification, both eyes open, unbeatable up close and on moving targets. See the red dot range.

Turrets, tubes and travel

Capped turrets stay where you set them and will not snag on a pack strap — the sensible choice if you zero once and hold over. Exposed tactical-style turrets are for shooters who dial for every shot; if that is not you, they are a liability in the scrub.

A zero stop, which physically prevents you dialling below your zero, is genuinely useful on any scope you turn regularly. A 30 mm or 34 mm tube gives more internal adjustment travel than a 1 inch tube, which matters if you shoot at distance or use a canted base; it does not, in itself, make the image brighter.

Check the total elevation travel against what you need. Remember that roughly half of it disappears keeping the reticle centred, which is why a 20 MOA canted base is standard practice for long-range work.

Mounting: where more scopes are ruined than anywhere else

Good glass badly mounted shoots worse than modest glass mounted properly. This is the least glamorous part of the purchase and the one with the highest return.

1. Degrease everything. Base screws, receiver holes, ring screws. Oil in a threaded hole means the screw will not hold torque.
2. Torque to specification, in sequence. Base screws and ring screws have published figures, and a torque driver costs less than one scope. Overtightening rings dents tubes and can crack a lens.
3. Set eye relief with the rifle shouldered in your normal shooting position, not on the bench. Then check it at the highest magnification, where eye relief is most critical, and again in a prone or awkward position.
4. Level the reticle to the rifle, not to the world. A canted reticle throws shots sideways as distance increases and the error grows the further you shoot.
5. Boresight before you burn ammunition. It costs nothing and saves a box.

We mount, torque, level and boresight at the counter at Roseville Chase. If you have bought glass elsewhere and want it done properly, bring it in.

Zeroing without wasting a box

Boresight first. Fire one round at 25 m to get on paper. Move to 100 m, fire three, measure from the group centre to the point of aim, and dial the correction — do not chase individual shots. Fire three more to confirm. Nine rounds is plenty; forty means you were adjusting off single shots.

Let the barrel cool between strings. A hot thin barrel will walk and you will spend the afternoon correcting a problem that is not in the scope.

Matching the scope to the rifle

A few pairings that work in practice:

• Rimfire for rabbits — 3-9x40 with an adjustable objective or side parallax that comes down to 25 m or less. Standard hunting scopes often park parallax at 100 m, which is blurry and imprecise at rimfire distances.
• Spring air rifle — glass specifically rated for spring guns. They recoil forwards as well as backwards and will destroy a conventional scope. The Nikko Stirling Air King range is built for it.
• Centrefire deer rifle — 2.5-10x42 or 3-9x40, capped turrets, illuminated duplex if you hunt the edges of the day. Weight matters because you carry it.
• Open-country and varmint — 4-16x or 5-25x, side parallax, exposed turrets with a zero stop, FFP if you dial. Pair it with a rangefinder, because guessing distance is what actually costs you the shot.

Our range spans Vortex, Leupold, Burris, Bushnell, Steiner, Meopta and Element Optics, with fixed power options as well. The whole rifle scope range is in one place. If you shoot at night, our guide to choosing a thermal scope covers a different set of trade-offs entirely.

Common questions

What magnification rifle scope do I need for hunting in Australia?

For most hunting, 3-9x40 or 2.5-10x42 covers the great majority of shots. Under 150 metres in thick country, a 1-6x or 2-7x acquires targets faster. Above 300 metres in open country, 4-16x or higher earns its place. Buy for your typical shot distance, not your longest.

Is MOA or MIL better?

Neither. They are different units for the same thing. MIL is decimal so the arithmetic is simpler; MOA is finer per click on most scopes and more common in Australian clubs. What matters is that your reticle and turrets use the same unit, so corrections need no conversion.

Do I need a first focal plane scope?

Only if you hold or dial precisely at varying magnifications. For hunting inside 300 metres, a second focal plane scope gives you a reticle that stays legible at every power, which is the more useful property. FFP suits competition and long-range shooting.

Does a bigger objective lens mean a brighter image?

Only to a point. Brightness at the eye depends on exit pupil, which is objective diameter divided by magnification, and your eye can only use about 7 mm. Lens coatings and glass quality affect light transmission more than diameter, and a large objective forces higher rings and a worse cheek weld.

How much should I spend on rings and bases?

More than feels reasonable. Mounting hardware is what holds your zero, and a quality set costs a fraction of the scope it protects. Degrease the threads, torque to specification and level the reticle to the rifle — badly mounted premium glass shoots worse than a modest scope mounted properly.

Can I use the same scope on an air rifle and a centrefire?

Not safely in one direction. Spring and gas ram air rifles recoil in two directions and will break scopes built for centrefire recoil, so a springer needs glass rated for spring air guns. Pre-charged pneumatic air rifles are recoilless and will run a conventional scope without trouble.

Disclaimer

This information is general information, not legal advice, collated from various online sources by an LLM assistant. In all cases refer to the NSW Firearms Registry for any legal or ownership matters. E&OE.