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FAQ

Why do your 80% Lowers cost so much?

Optimus Defense does not settle for second best. So as a result of using high quality material, state of the art manufacturing equipment & tools, highly skilled labor, and intricate designs, the cost to produce the Lowers is higher than average. But we think you will agree that Optimus Defense products are much better than average. Our Lowers are machined out of structural aircraft grade 7075-T651 aluminum, but some manufacturers machine their lowers out of less expensive and inferior 6 series aluminum material such as 6061-T6. The Lower was designed with manufacturing in mind, but it is not a simple design. So it takes a long time to cnc machine, and time is money. We also donate $20 for every 80% Lower to The Calguns Foundation.

Why is 7075 better than 6061 aluminum?

For structural parts like an AR-15 Lower Receiver, 7075 is a much better choice than 6061. 7075-T651 is about 150% the hardness, 180% the tensile strength, and 160% shear strength compared to 6061-T651. Note, the temper (heat treatment) of aluminum is also very important in its mechanical properties. Aluminum alloys get most of their strength from the temper. So do not settle for an aluminum with a T3 or T4 temper, because their hardness and strength is much less than a T6 temper. The temper T651 is a stress relieved version of T6 which reduces the chance of the machined part warping or "taco chipping" after it has been machined. At Optimus Defense aluminum parts that are structural and need to last for a long time (e.g. 80% Lower) are manufactured out of 7075-T651 and aluminum parts that do not need to be strong or last a long time (e.g. Painting T-Handle) are made out of 6061-T651.

How do I complete my Lower to make it a firearm?

We recommend using a manual mill, cnc mill, or the Optimus Defense Drill Jig to finish the manufacturing of your Lower Receiver. Completion Guides, Drawings, and a CAD model are provided on the Documents page.  And also look at the Tools page for products that will make completing your lower easier.

What does "Optimus" mean?

"Optimus" is a Latin word that translated means "best of the best".

Are you going to make any other products?

Yes. We have lots of ideas, but it takes time to design, prototype, test, redesign, etc. So check our website regularly to see what is new.  If there is a product that you would like us to develop, then let us know by contacting us.