Buckle up because Caleb and his guest Paul Noonan from FM Products are here to tell us what makes Foxtrot Mike parts unique. This means they have a LOT to talk about! FM's design philosophy can be summed up as "simple equals reliable," which their current Mike15 Gen2 operating system embodies. The Gen2 upper receiver does not need the traditional AR15 buffer, buffer spring, and receiver extension. Everything is contained inside the upper receiver. Some details on specific assemblies:

CHARGING HANDLE: Paul explains the evolution of FM's unique forward charging handle, which is both convenient to operate and optimized to prevent failures.

BOLTCARRIER: Aside from being about half the size of a standard AR15 BCG, FM's carrier is optimized for reliability. A recoil lug on the gas key nestles into the top of the carrier, adding an enormous amount of strength to make gas key screw failures very, VERY rare. For an extra measure of safety, the firing pin is springloaded to eliminate risk of a slamfire due to the inertia of the bolt slamming home. Even the extractor pin was redesigned so that if it fails, the extractor will continue to function! Every Foxtrot Mike upper comes with three spare extractor pins. Paul recommends replacing the pin every 2,000 to 3,000 rounds.

RECOIL SPRING / ROD: The nested, dual springs are wound in opposite directions so they won't interfere with each other, while the recoil rod nestles into the charging handle. Pulling the charging handle compresses the spring and moves the recoil rod back in a straight line. Simple and extremely reliable.

BARREL: Manufacturing a topnotch barrel is difficult and requires a lot of testing and checking of dimensions through the entire process. FM exerts extra care to make sure barrelmaking tools are not overused. What's an "overused" tool and why is it bad? Paul explains. Obvious physical differences on FM barrels include flats for a for a 1/2" wrench behind the muzzle threads, so you can support the barrel when you install a muzzle device. More flats are the rear anchor the barrel to help ensure maximum torque is applied when installing the barrel extension so it won't work loose over time.

All FM barrels are vacuumstress relieved to remove the stress caused by the button rifling process. This results in a longerlasting barrel because stressed steel is more brittle and wears faster. Chamber reaming is done with extreme care. All of this adds up to exceptionally accurate barrels. How accurate? Foxtrot Mike 9mm Luger barrels consistently achieve 1 MOA performance NOT an easy feat with 9mm!

GAS BLOCK / GAS TUBE: Variations in gas tubes can result in misalignment of the tube and the gas block, resulting in some gas loss, which can affect reliability. Some manufacturers solve this problem by making the gas ports larger on all their guns to ensure adequate gas flow for reliable cycling. The result is that many AR15s are overgassed guns. FM guns have just enough gas flow for reliable operation, which also minimizes recoil. Paul explains the FM process for making sure the gas tube, gas block, and barrel gas port are correctly aligned for correct gas flow.

TAPERLOCK BARREL NUT. The taper inside the nut is cut on the same machine that cuts the taper on the exterior of the barrel. This provides a much larger bearing surface than the little flange on the barrel extension. When the barrel nut is torqued down, the barrel naturally aligns concentrically to ensure superb accuracy.

PICATINNY RAIL ADAPTER: This comes with every FM upper receiver and fits in the rear of a standard AR15 lower receiver in place of the buffer tube. It lets you take full advantage of the Mike15 / Mike102 bufferless operating system by mounting an M1913 Picatinny folding stock on your rifle without having to buy a dedicated lower receiver.