Scope caps and covers
Best Scope Caps and Covers
Quick answer
The pick for most hunting scopes is a matched Vortex Defender Riflescope Flip Cap, Eyepiece E-10 and 44mm Objective Lens Cover pair at $48.00, because it is sized directly by the published objective diameter rather than by a catalogue index number that has to be matched against a separate chart.
Flip-up lens caps split into two sizing systems, and mixing them up is the single most common mistake in this category. One system, used by Butler Creek, sizes caps by a catalogue number that does not correspond directly to any millimeter or inch measurement. The other, used by Vortex and Monstrum, sizes caps directly by the published objective diameter or bell range in millimeters.
A Butler Creek size number is an index into the maker's own chart, not a measurement you can guess from the scope's specification sheet. The scope's own listed objective diameter, such as 50 millimeters, refers to the glass. The bell around that glass, which is the part the cap actually has to fit over, is wider than the glass and its outside diameter is rarely published by the scope manufacturer at all.
These recommendations are researched from published manufacturer specifications and owner-review consensus. Nobody on this site fitted every cap in this catalog to every scope in the catalog to confirm the sizing charts, and the guidance below exists specifically so you do not have to guess where a chart already exists.
On this page
- Why a Butler Creek size number is not a measurement
- How to measure your scope for a cap that actually fits
- Why the ocular cap matters more than most buyers expect
- Throw levers and sunshades: the rest of this category
- Beginner: the classic flip cap pair
- Intermediate: sized directly, no chart required
- Expert: the full weather and glare system
Why a Butler Creek size number is not a measurement
Butler Creek's own published sizing chart is the only reliable way to match a cap to a scope in this system, and the numbers in the chart do not scale in any obvious way with the diameter they describe.
Butler Creek Size 34 covers a 2.1 inch objective bell and Size 40 covers a 2.25 inch bell, which shows the size number is a catalogue index rather than a diameter you could infer from the scope's own listed objective millimeters.
Sourced figure
| Cap | Butler Creek size | Published bell diameter |
|---|---|---|
| Butler Creek Flip-Open Eyepiece Scope Cover, Size 11, 1.55 inch | Size 11, eyepiece | 1.55 in |
| Butler Creek Size 27 Objective Flip Open Scope Cover | Size 27, objective | Not published on this listing, check the maker chart |
| Butler Creek Size 34 Objective Flip Open Scope Cover, 2.1 inch | Size 34, objective | 2.1 in |
| Butler Creek Size 40 Objective Flip Open Scope Cover, 2.25 inch | Size 40, objective | 2.25 in |
Where a bell diameter is not published on the listing itself, Butler Creek's own published size chart, cross-referenced against your own measurement of the bell, is the only correct way to choose. Guessing from the scope's objective lens figure in millimeters is the mistake this table exists to prevent.
How to measure your scope for a cap that actually fits
- Confirm the rifle is unloaded. Open the action and check the chamber before handling anything mounted on the rifle. Leave the action open for the rest of this.
- Measure the bell, not the lens. Put a caliper across the widest outside point of the objective housing. This is the bell, and it is always larger than the glass diameter printed on the scope's own specification.
- Match against the maker chart. For a Butler Creek cap, take that measurement to Butler Creek's own published size chart rather than assuming the size number equals a diameter. For a Vortex Defender or Monstrum cap, the listing's millimeter range is the measurement itself.
- Measure the eyepiece separately. The ocular bell is a different diameter from the objective bell on almost every scope, and needs its own measurement and its own size, whether bought as a matched pair or separately.
Why the ocular cap matters more than most buyers expect
Most buyers spend all their attention on protecting the objective lens and treat the eyepiece cap as an afterthought, if they buy one at all. This is backward. Rain, snow, or fog on the objective lens is a problem you can often shoot through or wipe clear from a few feet away. Rain on the ocular lens sits inches from your eye, directly in the sight picture, and it is what actually stops you from taking a shot in bad weather, not water on the far end of the tube.
A matched pair, such as the Vortex Defender Riflescope Flip Cap, Eyepiece E-10 and 44mm Objective Lens Cover or Vortex Defender Riflescope Flip Cap, Eyepiece E-10 and 50mm Objective Lens Cover, ships with both caps sized correctly from the start. Buying a Butler Creek objective cap alone and skipping the eyepiece is the more common version of this mistake, and it leaves the lens that matters most in wet weather completely uncovered.
Throw levers and sunshades: the rest of this category
The same catalog section that holds flip-up lens caps also holds two other products worth knowing about, even though neither one is a lens cap. A throw lever, such as the Vortex 44mm Riflescope Throw Lever or the Monstrum Triton Scope Throw Lever, 44mm Diameter, bolts onto the magnification ring and gives your fingers real leverage to spin it quickly, which has nothing to do with lens protection but lives in the same accessory drawer.
A sunshade, such as the Athlon Optics 50mm Riflescope Sun Shade or the Nightforce Riflescope 3-Inch Anti-Glare Matte Sunshade, threads onto the front of the objective bell and controls glare and stray light rather than protecting the glass from impact or weather. A full neoprene cover, such as the Leupold Neoprene Scope Cover, Extra Large or the Burris Neoprene Breathable Waterproof Riflescope Cover, Large, wraps the entire scope body for a rifle that spends real time in a case or a scabbard, which flip caps alone do not address.
Beginner: the classic flip cap pair
This tier optimizes for the lowest cost to real lens protection, accepting the extra step of checking Butler Creek's own size chart rather than paying for a directly sized alternative.
Butler Creek Size 34 Objective Flip Open Scope Cover, 2.1 inch
$11.61A published 2.1 inch bell diameter behind its Size 34 catalogue number, at the lowest price point in this category for a real flip-up objective cap.
Best for: A hunting scope with a bell that measures out to roughly 2.1 inches, confirmed with a caliper rather than guessed from the objective lens figure.
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Butler Creek Flip-Open Eyepiece Scope Cover, Size 11, 1.55 inch
$11.95The correctly sized ocular half of the pair, sold separately in the Butler Creek system, and the cap that actually stops rain from ruining a shot opportunity.
Best for: Pairing with any Butler Creek objective cap so the lens closest to your eye is protected, not just the one furthest away.
Check price on AmazonIntermediate: sized directly, no chart required
This tier removes the catalogue index problem entirely by buying caps sized directly in millimeters against the published bell range, which is the buy-once answer for most hunting scopes.
Vortex Defender Riflescope Flip Cap, Eyepiece E-10 and 44mm Objective Lens Cover
$48.00A matched objective and eyepiece pair sized directly by millimeters rather than a catalogue index, fitting the 44 mm objective class common across mid-range hunting scopes.
Best for: A hunting rifle carrying a scope in the 44 mm objective class, where a matched pair removes any sizing guesswork.
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Monstrum Rubberised Flip-Up Rifle Scope Lens Covers, Objective Bell 43 to 48mm
$9.99A published 43 to 48 mm bell range printed directly on the listing, at a fraction of the Vortex Defender's price, for a buyer who wants the same direct sizing without the matched pair's cost.
Best for: A budget-conscious buyer whose bell measures inside the 43 to 48 mm range and wants a rubberized flip cover rather than a matched hard-shell pair.
Check price on AmazonExpert: the full weather and glare system
This tier is the performance ceiling for a precision rig that lives outdoors in real weather, pairing glare control with full-body protection rather than lens caps alone.
Nightforce Riflescope 3-Inch Anti-Glare Matte Sunshade
$35.99A published anti-glare matte finish controls stray light and mirage bloom on a precision scope used in bright, open conditions where flip caps alone do nothing for glare.
Best for: Long range shooting in open, sunlit terrain where glare off the objective lens is a real problem, not just a weather one.
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Leupold Neoprene Scope Cover, Extra Large
$28.99A full neoprene envelope over the whole scope body for a rifle carried through brush, in a scabbard, or in a case where flip caps alone leave the tube itself exposed.
Best for: A hunting rifle that spends real time slung over a shoulder or carried in a saddle scabbard rather than sitting in a rack.
Check price on AmazonWho should not buy this tier: Not for a rifle that spends most of its life in a case or a safe. A sunshade solves a glare problem a bench gun rarely has, and a full neoprene cover is overkill for a scope that is never carried through brush or rain.
How we chose
We did not test these optics in person and we never claim to. Picks are researched from manufacturer specification sheets, published optical and ballistic formulas, and the recurring themes in verified owner reviews. Every pick is matched to a real objective diameter, a real tube size, a real ring height or a real exit pupil rather than to a price bracket, and it is placed in the tier where its capability actually belongs. Where a figure is shooter convention rather than a sourced number we label it, and where a manufacturer does not publish a figure we leave it out instead of estimating it.
Sources
- Butler Creek published sizing chart
- Vortex Optics published specifications
- Monstrum published specifications
- Nightforce published specifications
Frequently asked questions
Why doesn't my scope's 50 mm objective match a size 50 Butler Creek cap?
Butler Creek size numbers are a catalogue index into their own published chart, not a diameter measurement. The scope's listed objective figure describes the glass, while the cap has to fit around the bell housing that surrounds it, which is always wider and is rarely published by the scope manufacturer at all. Measure the bell and check Butler Creek's own chart rather than matching the numbers directly.
How do I measure my scope for the right size cap?
With the action open and the rifle confirmed unloaded, put a caliper across the widest outside point of the objective bell, not the glass diameter printed on the scope. For a Butler Creek cap, cross-check that measurement against their published size chart. For a Vortex Defender or Monstrum cap, the listing's own millimeter range is the measurement to match directly.
Why does the eyepiece cap matter more than people expect?
Rain or snow on the ocular lens sits directly in your sight picture, inches from your eye, and is what actually stops a shot in bad weather. Water on the objective end is further away and often easier to shoot through or clear quickly. Buying only an objective cap and skipping the eyepiece protects the wrong half of the lens system first.
Are flip caps enough or do I need a full scope cover too?
Flip caps protect only the two lens surfaces. A full neoprene cover wraps the entire scope body, protecting the turrets, the tube finish, and the mounting hardware during transport in a case or a scabbard, which flip caps do nothing for. A rifle carried through brush regularly benefits from both.
What is a throw lever and is it a type of scope cap?
No. A throw lever bolts onto the magnification ring and gives your fingers leverage to spin it quickly between powers. It shares a catalog category with lens caps because both are small mounted accessories, but a throw lever has nothing to do with lens protection.
Do sunshades reduce parallax or just glare?
A sunshade only blocks stray light and glare from entering the objective lens at an angle. It has no effect on parallax, which is an internal focus mismatch between the reticle and the target image and is corrected with a side focus or adjustable objective dial, not with any accessory that mounts on the outside of the tube.
Researched, not professional advice. This page is compiled from published manufacturer specifications, published optical and ballistic formulas, and owner-review consensus, not hands-on testing. Figures described as a rule of thumb are shooter convention rather than sourced numbers, and they are labelled that way wherever they appear. Ballistic figures come from a point mass model using the ballistic coefficient the maker publishes, so treat them as a starting point and confirm them on paper at a measured distance. Confirm your firearm is unloaded with the action open before you mount, level, torque or bore sight anything. Verify a zero only on a supervised range or a safe, legal backstop, know what lies beyond your target, and follow the law where you hunt and shoot, including rules on land access and permitted cartridges.