Brand new!! F5 Manufacturing excited to announce the release of our multi-cal billet lower receiver and upper receiver set. Finished in black Cerakote for ultimate durability. This is a matched receiver set machined to exacting tolerances from a block of billet aluminum for maximum strength. These are perfect for your 223 Remington, 5.56 NATO, and 223 Wylde builds as well as 6.5 Grendel, 300 Blackout, 224 Valkyrie, and even 9mm (AR9) amongst other cartridges. We engineer and manufacture these from the ground up in house out of our shop in the United States of America.