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Ar-15 40l Low Profile Rear Sight - Ar-15 Flip-Up Adjustable 40l Low Profile Rear Sight Black
Our editorial team reviews specifications, product data, and field-use information to keep pages accurate.
$155.00
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SKU: 100003317
Overview
This low-profile flip-up rear sight is built for shooters who want a compact backup aiming solution on a Picatinny receiver rail. It is designed to work with A2-height front sights and can be co-witnessed through an optic, with dual apertures for close- and mid-range use. The spring-loaded sight deploys with a non-snagging lever, while windage adjusts in 3/4 MOA increments per click. Its aluminum base, steel apertures, and stainless hardware give it a straightforward, duty-oriented construction without unnecessary bulk.
Why Hunters Choose the A.R.M.S.
Flip-up Rear
Spring-loaded deployment for fast transition
Dual Apertures
Support close- and mid-range aiming
Compatible A2-height
A2-height front sights and optic
Mounts Easily
To a Picatinny receiver rail
Windage Adjusts
In 3/4 MOA increments per
Key Features
- Flip-up rear sight with dual apertures for close- and mid-range target use.
- Compatible with A2-height front sights and can be co-witnessed through an optic.
- Mounts to a Picatinny receiver rail for straightforward installation.
- Non-snagging lever releases the spring-loaded sight into the ready position.
- Windage adjusts in 3/4 MOA increments per click.
- Low-profile #40L design is calibrated for 250 and 300 meter combat ranges.
Best Used For
- Hunters using an optic who still want a co-witnessed backup rear sight on a Picatinny rail.
- Users needing a low-profile flip-up sight that stays folded until quickly deployed.
- Shooters pairing with A2-height front sights and wanting dual-aperture rear sight options.
- Those who prefer windage-adjustable sighting with 3/4 MOA clicks for close- and mid-range use.
Specifications
| Apertures | Steel, matte black |
|---|---|
| Apertures Count | Dual |
| Base | Aluminum, hardcoat anodized, matte black |
| Calibration | 250 and 300 meter combat ranges |
| Co Witness | Yes |
| Compatibility | A2-height front sights |
| Hardware | Stainless steel, matte black |
| Height Deployed | 1 5/8 in (4.1 cm) |
| Height Folded | 5/8 in (1.6 cm) from flattop |
| Length | 2 3/16 in (5.6 cm) |
| Mounting Type | Picatinny receiver rail |
| Nsn | 1005-01-575-3508 |
| Width | 1 3/8 in (3.5 cm) |
| Windage Adjustment | 3/4 MOA increments per click |
Pros
- Flip-up rear sight with spring-loaded deployment for fast transition to use.
- Dual apertures support close- and mid-range aiming options.
- Compatible with A2-height front sights and optic co-witness setups.
- Mounts easily to a Picatinny receiver rail.
- Windage adjusts in 3/4 MOA increments per click.
- Non-snagging lever and safety-wire-retained locknut help reduce loose parts.
Considerations & Trade-offs
- The dual-aperture layout is set up for close- and mid-range use, so it adds a bit of complexity compared with a single-aperture rear sight.
- The #40L is calibrated for 250 and 300 meter combat ranges, which may not match every rifle setup or preferred zeroing approach.
- As a flip-up rear sight, it is designed to be used with an optic or A2-height front sight, so it is not a standalone sighting solution.
- Its low-profile folded height helps reduce bulk on the rail, but the spring-loaded flip-up design still adds a mechanical component that must be deployed before use.
Suggested Comparisons
- Flip-up rear sights
- A2-height front sights
- Picatinny rail accessories
- Optic co-witness iron sights
Suggested Accessories
- Picatinny rail accessories
- A2-height front sight
- Optic mounting accessories
- Sight adjustment tool
Frequently Asked Questions
What type of front sight does this rear sight work with?
The product data says it regulates properly with A2-height front sights.
Can this rear sight be used with an optic?
Yes. The description says it can be co-witnessed through an optic.
How does the dual-aperture setup work?
The sight has dual apertures calibrated for close- and mid-range targets. The description says you can aim through both, or fold the first aperture down and use the second one.
How does it mount to the rifle?
It mounts to a Picatinny receiver rail.
What adjustments does it offer?
The #40L Low Profile has windage adjustment in 3/4 MOA increments per click, and it is calibrated for 250 and 300 meter combat ranges.