Brownells 75th Anniversary - A Shooting Heritage

Everything To Make Your Pistol-Caliber AR Ready for an Adjustable Stock

The FM Products 9mm Receiver Extension Assembly is a complete, one-stop package with everything you need to lay the foundation to install an adjustable, M4-type carbine stock on your 9mm-chambered AR-15. It includes the extension (buffer tube) itself, made from an extremely strong yet lightweight 7075 T6 aluminum extrusion.

The FM Products 9mm Receiver Extension is hardcoat anodized to resist surface wear, before application of a dry film lube coating that aids in smooth movement of the buffer inside and the stock outside.

  • Mil-spec (1.14" O.D.) buffer tube accepts M4-type adjustable carbine stocks
  • 6 notches for setting stock position
  • Correct-weight (6.5 oz.), extra-long buffer - no spacers required
  • Stainless steel music wire recoil spring helps ensures reliable cycling with all loads

The core of the FM Products 9mm Receiver Extension Assembly is the Foxtrot Mike 9mm Heavy Buffer of the correct weight and size to properly cycle blowback operated 9mm AR-15s with minimal bolt bounce. It’s made of pre-hardened 8620H carbon steel that’s "H" rated to ensure harder core hardness than standard 8620 steel.


Big Book Catalog, Issue:72, Page:050


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