Atrius Development X-Series Heavy Ambidextrous Forced Reset Selector

The Atrius X-Series Heavy is the full-size MCX Spear Forced Reset Selector. It is an ambidextrous selector with a trip base and a trip clutch, built for SIG's MCX Spear in .308 Winchester and 6.8x51, also called .277 Fury. That host is the civilian full-size Spear, not Spear LT, not Rattler, and not MPX.

This selector is not the regular X-Series. Regular X-Series remains the MCX, MPX, Rattler, and Spear LT part. Heavy ships a new FRS lever dimensioned only for the full-size Spear. Atrius states the X-Series FRS cam lever is unique and incompatible with other FRS models, so Heavy levers do not swap onto a regular X-Series or an AR-15 Atrius selector.

Configuration is Safe, Semi, and Super-Semi. Construction is heat-treated 4140 steel with a corrosion-resistant black nitride finish, made in the USA. Atrius calls the install drop-in with no modifications and no trigger cutting. After the selector and fire control group go in, the trip base seats on the left side of the receiver against the rear trigger pin, the trip clutch rides the trip-base track, and the trip base tucks under the rear takedown pin before a dry function check.

The trigger path is the mil-spec trigger that ships with MCX platforms, plus other single-stage mil-spec triggers that do not have a U-notch or relief cut. This is not the G-Lever. G-Lever remains the Atrius SKU with extra Geissele and reduced-hammer compatibility, and Heavy has no lever blocker. Restricted destinations include California, Connecticut, Colorado, Delaware, Florida, Hawaii, Illinois, Maryland, Massachusetts, Minnesota, Nevada, New Jersey, New York, Oregon, Rhode Island, Virginia, Washington, the District of Columbia, US territories, and international shipping.