This weapon is built with the LMT® patented Monolithic Rail Platform, MRP®. The only true monolithic rail platform, milled from a single solid piece of aerospace aluminum forging. It utilizes two locking bolts accessible from the side of the receiver to lock in the barrel extension. This patented technology engages the barrel extension for a full 360 degrees around the extension and makes the barrel removable within seconds with a return to zero of the same barrel. One receiver can utilize numerous barrels of varying length, material, and caliber.

Monolithic rail platform barrels utilize a low profile gas block and straight gas tube.  They possess proprietary coating and are cryogenically treated for long term durability.

The MARS®-L ambidextrous lower receiver features the EDM machined two-stage trigger, winter trigger guard, endplate with QD swivel point, LMT® ergonomic textured grip, and SOPMOD stock.  The ambidextrous features include bolt catch and release, magazine catch, and safety selector.  As with all LMT® lower receivers, the extension tube is coated with dry film lubricant.