Product Description

AMBI Milspec Active Reset Conversion — AMBI MARC

The AMBI MARC is a 3-position forced-reset-style conversion designed around the familiar feel and operation of a traditional mil-spec safety selector, now in an ambidextrous configuration.

Currently In two Configurations:

Left handed Bias (Short Left side Selector, Standard Right side Selector)

No Bias ( Both Standard Length Selectors)

- . Please refer to the product photos for specific lever orientation and configuration details.

The MARC is designed with durability, reliability, and proper mechanical interaction in mind.

Product Features

Compared to similar products on the market, the MARC lever arm features:

• Properly heat-treated S7 tool steel with a nitride finish

• 4140 steel selector components

• Correctly dimensioned interacting surfaces to help prevent binding during operation

• Rounded edges to reduce stress concentration and help prevent cracking

• A design focused on long-term durability and reliable function

AMBI MARC Compatibility Information

The following compatibility chart is based on our personal testing and experience. This list is not exhaustive, and inclusion or omission from this chart does not guarantee compatibility in every possible configuration.

There are many variables involved, including lower receiver dimensions, trigger tolerances, buffer setup, bolt carrier geometry, and installation quality.

Standard Test Configurations

Our standard test configurations include:

• Aero Precision Gen 2 lower receiver

• Aero Precision M4E1 lower receiver

• Standard carbine buffer tube with carbine spring and H2 buffer

• A5 buffer tube with A5 spring and H1 buffer

Required Setup Notes

The AMBI MARC requires:

• An M16-cut bolt carrier group

• A low-shelf lower receiver, or a lower modified to a low-shelf configuration

• For certain Geissele triggers, our Geissele Over Travel Stop must be installed

AMBI MARC-Compatible Trigger Chart

* Some two-stage triggers may require minor polishing or small material removal on the top/rear portion of the trigger shoe tail. This is generally due to increased trigger shoe travel in two-stage models and tolerance stacking between interacting parts.

Important: Triggers listed as “Yes, modification required” should not be purchased for use with the MARC unless the end user is willing and able to perform or have performed the required fitting.

General Tuning Recommendations

These are general recommendations based on our personal experience. Your specific setup may require additional tuning depending on barrel length, gas system, ammunition, suppressor use, buffer system, and overall rifle configuration.

9mm Blowback ARs

Blowback 9mm AR platforms can create significantly more stress on fire-control components if not properly tuned. At this time, we strongly recommend using a 10 oz or heavier buffer, or the heaviest captured/hydraulic buffer system available, when using the MARC in a blowback 9mm configuration.

Improper tuning may cause premature wear. Warranty coverage may not apply in cases of negligent misuse, improper installation, or clearly abusive configurations.

Design and Function Statement

The AMBI MARC may operate on similar broad mechanical principles as other active-reset-style products; however, it was developed as a distinct product with its own geometry, material selection, component design, and functional improvements.

The MARC design prioritizes:

• Durable material selection

• Proper part interaction

• Reliable reset behavior

• Reduced wear points

• A familiar mil-spec-style selector feel

• Long-term mechanical reliability

These improvements reflect independent engineering decisions intended to create a more durable and refined product.

Legal and Compliance Notice

The AMBI MARC is designed and intended for lawful semi-automatic operation only. When properly installed and left unmodified, the product is intended to produce one discharge per individual trigger pull.

It is the responsibility of the end user to understand and comply with all applicable federal, state, and local laws before purchasing, installing, or using this product.

For federal legality concerns, customers may review applicable ATF materials and legal determinations related to forced-reset-style trigger systems.

Intellectual Property Statement

The MARC was independently developed and does not use any third-party CAD files, proprietary technical data, or protected design materials.

While the MARC may share general functional concepts with other semi-automatic trigger reset systems, the product incorporates its own component geometry, material choices, selector profile, mechanical interaction, and exterior design features.

Any questions or concerns regarding product design, function, legality, or intellectual property may be directed to us before taking further action. We are committed to good-faith communication and transparency.