Lima Six 5.56 NATO Belt Fed Upper Receiver /w Your Choice Of A Franklin Armory Essential Binary Or Atrius Forced Reset Selector

Tactical Shit in partner with Lima Six has been given 50 allocated upper receivers from their 2nd batch!

The Lima Six is a game-changing upper receiver that installs on any mil-spec AR15 or M16 lower receiver and provides belt fed capability. While a few parts must be swapped on the lower receiver, no permanent modifications or gunsmithing is required. Please read the entire product description for important technical information before ordering.

The Lima Six WILL NOT FUNCTION with a standard AR15 buffer setup. INCLUDED IN BUNDLE IS Buffer Upgrade Kit for Lima Six (A5 buffer tube, H3 buffer, and Sprinco Orange spring)

The Lima Six features a patent-pending stretched upper receiver, which provides an additional ~3/4″ of bolt carrier group travel compared to a standard AR15. This is a critical improvement for a belt fed firearm, as this additional travel assists in delinking rounds from the links. It also results in lower perceived recoil, and a more controllable rate of fire. No other belt fed AR15 on the market has this upgrade!

Additionally, the Lima Six features a top cover unlike any other belt fed top cover available, with a tensionable front pivot, two-point latch engagement, and an adjustable set-screw to take up any slack that may be present. These features result in an extremely reliable ability to hold zero even after repeated opening and closing. Initial testing shows that sub 2-MOA accuracy is achievable, which is unheard of for a belt fed firearm.

The Lima Six is compatible with standard AR15 barrels, although certain considerations need to be considered before swapping barrels.

Will start shipping MID FEBRUARY.

This product from Atrius Development allows you the option to “force the reset” of your qualifying milspec or other trigger so that you can pull the trigger faster. Only one shot is expelled of each single pull of the trigger.

The Atrius Ambidextrous Forced Reset Selector (FRS) is the most robust three-position selector solution on the market, engineered to give the shooter a true advantage: SAFE, SEMI (traditional), and SUPER-SEMI. Built for mil-spec AR-15 fire control groups chambered in .223 / 5.56 / .300 BLK, the Atrius FRS installs as a drop-in replacement with no fire-control modifications required, delivering rock-solid engagement and repeatable performance for range, competition, and field use (including hunting setups).

Reliability was central to the design. The Atrius FRS is optimized for mil-spec triggers that do not have a relief cut—i.e., the rear of the bottom half of the trigger must be completely squared off (not a U-notch). Your lower receiver must feature an FA pocket or low shelf, and the system must be used with an FA bolt carrier group. We strongly recommend H2 or H3 buffer weights to ensure consistent, reliable operation across shooting conditions.

Performance highlights include an ultra-smooth, crisp 90° throw with tactile clicks and engineered positive positioning to eliminate slippage or accidental movement during use. The mechanically leveraged FRS design reduces wear on internal rifle components compared with many forced-reset trigger systems, extending service life. Aggressive, chamfered ergonomics and textured surfaces give immediate, confident thumb purchase under stress or while wearing gloves. Constructed from heat-treated 4140 steel with a corrosion-resistant finish, the Atrius FRS is built to resist the elements and the rigors of heavy use.

Installation is straightforward — swap your factory selector and be back behind the trigger in minutes (some fitment may be required depending on lower tolerances). Proudly Made in the USA.

Shipping & purchase limits: Please allow 4-6 weeks to ship. Limit 3 per customer.

Legal notice: By purchasing this product you acknowledge you understand and will comply with all applicable federal, state, and local firearms laws. Laws regarding firearm parts and accessories vary by state; it is the buyer’s responsibility to confirm legality where they live. Atrius Development Group does not guarantee legality in your jurisdiction and is not responsible for misuse or illegal activity. By completing your purchase you confirm you are complying with all applicable regulations.

I agree to indemnify and hold harmless the seller, manufacturer (Atrius), and affiliates from any claims, damages, or legal actions arising from my purchase, use, or misuse of this product.

This purchase is for personal use; I will not resell, distribute, or transfer without ensuring recipient compliance.

The Atrius is Restricted in these states: Not for sale or shipment to CA, CT, DE, FL, HI, IA, IL, MA, MD, MN, NJ, NV, NY, OR, RI, VA, WA, D.C. No US Territories. No international orders.

The Binary Firing System GEN 3 (BFSIII) is a 3-position trigger. In position 3 it fires one round on pull and one round on release, making this trigger ideal for both tactical and competition use. The BFSIII provides greatly reduced split times between rounds, allowing for tighter groups. The AR-Essential trigger comes with just the essential trigger components needed to install the Binary Trigger into your AR. This makes the the AR-Essential trigger a cost effective trigger option.

NEVER ALTER ANY COMPONENT OF THE BFSIII.
Improper installation, use, or tampering with the BFSIII will void the warranty and MAY LEAD TO UNINTENTIONAL DISCHARGE OF THE FIREARM THAT MAY LEAD TO INJURY OR EVEN DEATH.
Sales are Final, no returns once installation has been attempted
By purchasing this product, you are accepting responsibility and liability for the serviceability of the final installation.
AFTER THE BFSIII HAS BEEN PROPERLY INSTALLED, IT IS IMPERATIVE THAT ALL USERS SEEK QUALIFIED TRAINING ON HOW TO USE THESE PRODUCTS.
Trigger pin size is.154″
No 80% lowers, No polymer lowers, No Carbon lowers
Patent No. 9,952,012 ; 9,952,013 ; 10,107,580 ; 10,393,461 ; 10,480,881 ; 10,480,882 ; 11,085,724 & 11,226,165

Warning:

The Binary is not for civilian sales in: CA, CT, DC, DE, FL, HI, IA, IL, MA, MD, MN, NJ, NY, OR, RI, VA, and WA