Trijicon ACOG TA31-D 4x32 Red Crosshair with RMR
- Magnification Minimum: 4x
- Magnification Maximum: 4x
- Objective Lens Diameter: 32 mm
- Night vision: No
Last refreshed Jun 22, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A combat-tested magnified optic that performs well for long-range shooters willing to work around its short eye relief, so buy from a source you trust given at least one counterfeit report.
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ASIN: B073Y3TF23Model: ACOG ECOS 4x32Category: Rifle Scopes
More from this brandAll Trijicon rifle scopesOverview
A 4x32 ACOG with a battery-free tritium and fiber optic reticle comes paired with a mounted RMR Type 2 red dot, giving one housing both a magnified long-range sight and a fast close-quarters option. The aluminum-alloy housing carries a Flat Dark Earth Cerakote finish built to combat-use standards.
One reviewer also reported receiving a counterfeit unit with the wrong finish color and no Trijicon markings, a seller authenticity issue worth flagging before you buy.
- Battery-free tritium and fiber optic reticle
- 7075-T6 aluminum alloy housing, FDE finish
- RMR Type 2 sight included and mounted
- Both eyes open Bindon Aiming Concept design
Who it's for
Fits shooters who want a rugged, battery-free magnified optic for mid to long range work and are comfortable with the ACOG's short eye relief and narrow field of view. Not a match for anyone with astigmatism, since the tritium reticle can appear blurry regardless of glass quality, and returns on this item are restricted.
Pros and cons
- Battery-free reticle brightens automatically with light
- Reported accurate to long range when properly mounted
- Combines magnified and red dot sighting in one unit
- Short eye relief, narrow field of view
- Tritium reticle can be unusable for astigmatism
- Non-returnable once tritium seal is broken
- At least one report of a counterfeit unit
Specifications
| Brand | Trijicon |
|---|---|
| Model | ACOG ECOS 4x32 |
| Dimensions & fit | |
| Objective Lens Diameter | 32 mm |
| Item Weight | 1 pound |
| Construction & materials | |
| Material Type | Metal |
| Compatibility & installation | |
| Compatible Devices | Rifle |
| Included components | |
| Unit Count | 1 |
| Warranty & support | |
| Warranty Description | 1 year |
| Other details | |
| Magnification Minimum | 4x |
| Magnification Maximum | 4x |
| Night vision | No |
| Sport Type | Hunting |
| Reticle Type | Crosshair |
| Field Of View | 36.8 feet |
Frequently asked questions
Does the Trijicon ACOG TA31-D-100553 need batteries?
No. The reticle illuminates using tritium and fiber optics that respond to ambient light, with no battery required.
Can I return the Trijicon ACOG if the reticle doesn't work for my eyes?
According to one buyer's experience, Amazon lists this as non-returnable because of the tritium component, so try to confirm reticle visibility, including any astigmatism concerns, before ordering.
How does this ACOG mount on a bullpup rifle like a Tavor?
One reviewer reported the RMR could only zero at 50 yards on a Tavor, with impact drifting low at closer distances and eye relief tight enough to interfere with the backup iron sights.