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Foxtrot Mike (FM) Products AR-15 5.56MM Mike-15 Gen 2 Complete Upper Receiver - 12.5" (Rainier Arms Exclusive)

AR-15 Complete Upper Receiver

Special Price $589.95 Regular Price $649.95
Rainier Arms Exclusive

The all new FM-15 Gen 2 complete upper receiver incorporates several novel and patent pending ideas into one of the most innovative AR-15 style uppers on the market. 

The integrated, proprietary recoil system allows for the upper to function without the need for a buffer and buffer tube. This smaller, lighter, and more portable setup allows you to shoot with a stock or brace in the folded position! The included Picatinny adapter converts any standard AR-15 lower to accept many of the popular 1913 style folding stocks or braces. 

The slim 11.75" MLOK compatible handguard features a patented 4-position, non-reciprocating front charging handle which makes for fast reloads and weapons manipulation, as the handle can be placed on either side, up or downward facing, depending on your preference. 

The FM-15 Gen 2 includes a patent pending, fail proof mid-length gas system, featuring an all new 3-position, click-adjustable gas block. 

Easily change gas regulator positions without removing the hard guard, quickly moving between suppressed and unsuppressed, with a third "dirty" setting for hard use or underpowered imported ammunition. 

All FM fail proof gas blocks feature an indexing tab and are double pinned to the barrel to ensure there is no way the gas block can move or come loose during operation, and the top verification port is used during assembly to confirm perfect port alignment between the barrel, gas block, and gas tube. 

Other features include a monolithic style upper/handguard interface, patent pending true torque technology when installing the barrel extension, and a long taper lock barrel nut for extreme barrel concentricity and handguard rigidity.


  • Caliber: .223 Wylde

  • Barrel Length: 12.5"

  • Twist: 1:8"

  • Gas Length: Mid

  • Handguard: 11.75" M-LOK

  • Muzzle: A2 Flash Hider

  • Bolt Material: 9310 MPI tested

  • Carrier Material: Machined from premium 4340 HT material, machined in a hardened state.  Coated in QPQ

  • Upper Material: 7075 T6

  • Handguard Material: 6061 T6

  • Barrel: Premium Milspec 41V50 (Gerdau), vacuum stress relieved.  Match Grade .223 Wylde - Burnished Chamber, 1-8 twist rate, button rifled.  

  • 3 position, click adjustable gas block

  • Billet Pic-Rail buffer with Urethane Buffer

  • Comes with a picatinny rail adapter

  • Weight: 4 lbs

More Information
Product Type AR-15 Complete Upper Receiver
Manufacturer Foxtrot Mike
Color Black
Gas Length Mid
Rail Length 11.75"
Barrel Length 12.5"
Caliber 5.56 NATO
Threaded Yes

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