They've told us what makes the Foxtrot Mike Gen2 operating system unique, and they've done a deep dive on FM's upper receivers. Now, it's time for Caleb and his guest Paul Noonan from FM Products to give us the deets on Foxtrot Mike LOWER receivers. Paul's philosophy is that the customer should be free to build their gun exactly the way they want it same way we think here at Brownells! Building it yourself gives you an indepth understanding of how the gun works that you just can't get otherwise.
Which lower you choose depends on which Foxtrot Mike upper you have or want. If it's a Mike102 upper designed for use with AK magazines, you'll need the corresponding Mike102 lower receiver. You can get a complete lower fitted with a stock and fire control system. Or you can get a stripped 102 lower, which comes with a Picatinny Rail Adapter that lets you install an M1913 Picatinny folding stock, such as the excellent Midwest Industries Alpha Stock.
If your interest runs closer to a standard AR15 or you have the Mike15 upper receiver, you can get a Mike15 lower receiver fitted with a Magpul Zhukov folding stock OR with the Picatinny Rail Adapter and a THRiL pistol grip. Good news: the Mike15 lower receiver is compatible with Brownells BRN180 upper receivers.
FM lowers look noticeably different from a standard milspec AR15 lower receiver. All the edges are neatly rounded, so no matter where you grab the rifle, it'll fit comfortably in your hand. The swoopy, flowing, ergonomic curves around the magwell are the result of careful 3D machining, not just simple beveling. The magwell opening is, of course, flared to help guide that magazine home cleanly.
Caleb likes the Picatinny Rail Adapter because you can install the adapter first, THEN install the rear takedown pin detent and spring. You don't have to sprout an extra pair of hands to wrangle those fiddly parts while you're installing the adapter. This reduces the chance of losing the detent or getting a kink in the spring definitely the wrong kind of kink. Below the Picatinny rail itself, there's a handy socket for a pushbutton QD (quickdetach) sling swivel.
What if you want to build the rifle yourself but rather not track down the parts separately? Try a Foxtrot Mike Build Kit. These kits contain ALL the parts you need to build a complete rifle EXCEPT for the stripped lower receiver. If you already have a spare stripped lower (who doesn't?), you're good to go.
The great thing about building your own Foxtrot Mike gun is you get an intimate, detailed understanding of how every part of that gun works and how all the components work with each other. If a functional problem ever arises with gun, you have the knowledge base to troubleshoot it and fix the problem.