Fostech Echo AR II Drop In Binary AR-15 Trigger

Here’s a clean, factual product description for the Fostech Echo AR II Drop In Binary AR-15 Trigger:

“`html

The Fostech Echo AR II binary trigger transforms your AR-15 platform into a faster, more responsive system by firing on both the pull and release of the trigger. Designed for competitive shooters and tactical applications, this drop-in unit delivers consistent performance without compromising reliability.

What you get

• Complete drop-in trigger assembly with proprietary binary fire control group
• Hardened steel components with precision machining tolerances (±0.0005″)
• Adjustable 3.5-4.5 lb pull weight (factory set at 4 lbs)
• Tool-less selector switch for standard/binary mode transitions
• Includes anti-walk pins and MIL-SPEC hammer spring

Build and finish

The Echo AR II uses case-hardened 8620 steel for the hammer and trigger, with a black oxide finish that withstands carbon buildup and corrosion. The sear engagement surfaces are hand-polished to a mirror finish, reducing friction for smoother operation across thousands of cycles.

Unlike some binary triggers that require extensive gunsmithing, the Echo AR II arrives as a self-contained cassette-style unit. The housing is CNC-machined from 7075-T6 aluminum with Type III hardcoat anodizing, ensuring dimensional stability even during rapid-fire strings. All springs are chrome silicon for consistent tension retention.

Compatible platforms

• AR-15/M4 pattern rifles (5.56/.223)
• AR-9 PCC platforms with modified bolt carriers
• AR-10/LR-308 rifles (requires Fostech Echo AR-10 model)
• Not compatible with AK platforms or piston-driven ARs

Installation notes

Installation requires removing your existing fire control group and dropping in the Echo AR II unit—no modifications to the lower receiver are needed. The included anti-walk pins prevent lateral movement, and the assembly fits most mil-spec lowers with proper clearance for the selector lever.

For shooters who demand faster follow-up shots without venturing into NFA territory, the Fostech Echo AR II provides a legal alternative to full-auto fire. Its robust construction and predictable reset make it equally viable for 3-gun competitors and defensive carbines where shot placement matters.

“`