Mount your scope as low as it will go while still clearing the barrel, bolt and turrets, and set it forward or back so you see a full picture instantly at your natural cheek weld, checked at the highest magnification. Level the reticle, then torque the screws to the ring maker's figures. Get those three things right and the scope performs as its maker designed it.
The most common scope mounting mistake in Britain is not stripped threads or a tilted reticle. It is buying rings a size too tall "to be safe", then spending years lifting a chin off the stock to find the sight picture. Everything about a scope's image, from the full field of view to a forgiving eyebox, assumes your eye sits on the scope's axis at the right distance every time. Ring height and eye relief are how you make that happen.
Key takeaways
- The right ring height is the lowest that clears the objective bell, the bolt handle and the turrets.
- Eye relief on hunting scopes is usually about 80 to 100 mm; set it at maximum magnification, where it is tightest.
- Level the rifle first, then level the reticle to it; your eye cannot do it reliably.
- Typical ring cap torque is about 1.7 to 2.5 Nm (15 to 22 in-lb), but the ring maker's figure always wins.
- We do not stock scope rings or scope mounts, only red dot mounts, so source rings from a specialist.
Measuring ring height properly
The correct ring height is the lowest that clears everything. The lower the scope, the closer your eye stays to the natural line of the stock and the more repeatable your head position. "Clears everything" means three checks, not one:
- Objective bell to barrel. The classic constraint. Measure the outside diameter of the objective housing, not the quoted lens size (a 50 mm objective sits in a noticeably wider bell), halve it, and compare it with the height from the ring centre to the barrel. Allow for any barrel taper and the space a flip-up lens cover takes.
- Eyepiece to bolt handle. On many actions, especially with the large eyepieces of modern variable scopes, the bolt handle's arc hits first. Work the bolt with the scope loosely in place before torquing anything.
- Turrets and saddle to anything else, such as iron sight bases, rail edges or a moderator. Rare, but cheaper to check than to discover.
Ring makers quote height differently, some to the ring centre and some to the bottom of the ring, so convert to the same reference before comparing brands. A couple of millimetres of clearance over the barrel is enough; daylight under the objective is not a fault to fix.
The exception to "as low as possible" is deliberate. Straight-line stocks with high combs, and rifles set up for a head-up stance, can genuinely need taller mounting. That is why AR-pattern rifles usually put the optic's centre about 38 mm (1.5 in) above the rail. SIG's ALPHA-MSR mount, supplied with TANGO-MSR LPVOs, is listed by SIG at 1.535 in on the FFP 1-6x24. Height should follow the stock and your neck, not fashion.
Eye relief: set the distance before you chase the picture
Eye relief is the distance from the eyepiece at which the scope shows its full image. It varies by design, and the makers' own figures show the range:
| Scope | Type | Eye relief (maker's figure) |
|---|---|---|
| Burris Fullfield E1 3-9x40 | Hunting scope | 79–86 mm (3.1–3.4 in) |
| Burris Signature HD 3-15x44 | Hunting scope | 89–97 mm (3.5–3.8 in) |
| SIG Sauer TANGO-MSR 1-6x24 | LPVO | 100 mm at 1x, 95 mm at 6x (3.93–3.74 in) |
| Burris Scout 2.75x20 | Forward-mounted scout scope | 216–356 mm (8.5–14 in) |
Eye relief is not a suggestion. Too close and heavy recoil brings the eyepiece into your eyebrow: the crescent-shaped cut known as scope bite. Too far and the image shrinks into a tunnel with a black rim that steals field of view just when an animal steps out.
Set it by trial, at the magnification where eye relief is tightest, which on most variables is the highest:
- With the rings snug but not torqued, close your eyes, mount the rifle naturally from your normal position (prone if you shoot prone, sticks if you use sticks), and open your eyes.
- Slide the scope forward or back until the image is instantly full, with no searching. Your head should not move to meet the scope; the scope moves to meet your head.
- Repeat from each position you actually shoot. Where they disagree, favour the position with the most recoil and the highest stakes.
Do this before the final torque and before zeroing, because moving the scope afterwards means starting again. When comparing rifle scopes, read the eye relief with your cartridge in mind: around 80 mm is fine on a .223 and a poor partner for a light .30-06.
Level, then torque, in that order
A tilted reticle costs you sideways at distance: dial or hold for elevation with the reticle rotated a few degrees and part of that correction goes sideways. The scope must be level relative to the rifle, and your eye is a poor judge of it once the rifle is in your hands.
The reliable method uses two references. Level the rifle itself with a small spirit level across the action or scope base, then level the scope to match, either with a second level on the elevation turret cap or by hanging a plumb line a few metres away and turning the scope until the vertical wire follows the string. Wedge and feeler-gauge kits under the turret saddle do the same job. Eyeballing it against a fence line does not.
Then, and only then, torque with an actual torque driver:
| Fastener | Typical range | What each end of the range prevents |
|---|---|---|
| Ring cap screws | Commonly about 1.7–2.5 Nm (15–22 in-lb) | Too loose: the scope slips under recoil. Too tight: a dented tube and a scope that will not track |
| Base or rail screws | Commonly about 2.8–3.4 Nm (25–30 in-lb) | Too loose: the whole zero moves. Too tight: stripped action threads |
| Cross-bolt or rail clamp | Varies widely; check the maker's figure | Loose clamps walk along the rail; over-tight ones distort it |
These are typical published ranges, not universal law. The figure in your ring maker's instructions always wins, and aluminium, steel and shimmed rings all want different treatment. Tighten cap screws gradually and alternately, so the gaps each side of the ring stay even. A drop of mild threadlocker on steel screws is sensible; never use the permanent grades.
When the stock is the real problem
If after all this you still lift your cheek off the stock to see through the scope, the rings were not the mistake. The stock was shaped for iron sights or lower-mounted scopes. Mounting the scope higher is the wrong fix. Bring the comb up to your eye instead: an adjustable comb if the stock has one, or a strap-on cheek riser if it does not. The test is simple: close your eyes, mount the rifle, open them. A correct setup shows the full sight picture immediately, ten times out of ten.
The same rule applies to red dots on rifles. They come in a range of mount heights for exactly this reason, and the choice among red dot sight mounts follows the same logic; see the red dot mount height chart.
Expert tip
Before the first zeroing shot, mark a witness line across each ring joint and base screw with a paint pen. One glance at the start of each season shows whether anything has moved, and a smeared line after a lost zero tells you exactly where to look first. Then follow our zeroing guide.
We do not stock scope rings, scope mounts or torque drivers, so buy those from a specialist. If your scope is an LPVO, the SIG TANGO-MSR range comes with a cantilever mount; our LPVO guide explains why that matters.
Frequently asked questions
How do I know if my scope rings are too high?
Your face will tell you. If your cheekbone floats off the stock, or you have to nod down to find the picture, the scope is above your natural eyeline. Either the rings are taller than needed, or the comb is too low for a correctly low mount.
What happens if I mount a scope with too little eye relief?
Under recoil the rifle moves back several centimetres before your body stops it, and the eyepiece can hit your eyebrow: scope bite. It happens most with light rifles in bigger calibres and on steep uphill shots.
Do I need a torque driver for scope mounting?
For consistent results, yes. The gap between "slips under recoil" and "dented tube" on ring cap screws is small, and hand-tightening often misses it. A torque driver costs a fraction of a ruined scope.
Should scope rings be lapped?
With modern, well-made rings on a flat rail, usually not, and lapping removes any protective finish inside the ring. It can help with budget rings, two-piece bases on an uneven action, or a scope that keeps slipping despite correct torque.
Shop this guide
- Rifle Scopes — eye relief and tube size listed for every scope.
- LPVO Rifle Scopes — including SIG models supplied with a cantilever mount.
- Red Dot Sight Mounts — the only mounts we stock.
