Optimus Defense AR-15 80% Lower was designed for the tactical and precision shooter who wants a lower capable of performing to the highest level. Several months of design, manufacturing, and testing went into the development of this product to create one of the best AR-15 80% Lowers.
- Precision machined out of 7075-T651 aluminum plate by a California company that manufactures parts for major aerospace companies.
- Flared and slightly oversized magwell with a 25 degree taper angle for smooth/fast magazine loading/unloading of both mil-spec metal magazines and also polymer magazines (tend to be slightly larger).
- Front of receiver is about 1/2" longer than mil-spec to allow for a better hold when using gloves or if you have big fingers.
- Solid and oversized winter trigger guard that is compatible with most gloves.
- Reinforced around buffer tube thread.
- Exterior edges are CNC chamfered to eliminate sharp corners or edges that can snag on clothing/gear or be uncomfortable to your hands.
- Tight fit (small side of mil-spec tolerances) for pivot & take-down pin holes, upper receiver lug slots, and upper mating profile. Reduces slop and rattle of lower to upper interface.
- Optional mil-spec or easy install Pivot Pin Detent force.
- Vibro finished to remove sharp edges and machining marks.
- Marked: CAL. MULTI
- Compatible with mil-spec lower parts.
- Compatible with most pistol grips including grips that have a front tab, such as TangoDown grips.
- Compatible with mil-spec metal magazine and polymer magazines including Magpul Gen3 PMAGs.
The lower was also designed to be easy for the user to complete the remaining machining necessary to make it a firearm.
- Bottom of trigger guard is parallel to upper receiver mating face, which allows the lower to be leveled and clamped easily in a vice.
- Slot for upper's rear take-down pin lug is already precision machined and chamfered for a tight fit.
- Can be painted (Cerakote is recommended), anodized, or just left in the vibro finished condition.
- Compatible with most AR-15 lower drill jigs, and specificly fits the Optimus Defense AR-15 Drill Jig.
- CAD model for CNC programming.
- Drawing for manual machining dimensions.
- Drawing for inspection dimensions.
- Completion Guides that shows how to maually mill or drill the receiver.
No FFL required. This item is not a firearm. This is not a complete receiver. Machining of the trigger pin hole, hammer pin hole, safety selector hole, fire-control pocket, and trigger slot has not been completed.
Optimus Defense has a letter from BATFE stating that this 80% Lower is not a firearm.
For each Optimus Defense AR-15 Lower purchased though this website, Optimus Defense will donate $20 to The Calguns Foundation.