Directly patterned off the M16/M4 platform, the FN-15 MD Heavy Barrel Rifle is a rock-solid rifle built to take a beating. They are quite popular as well, and we decided to put it through its paces. Without wasting any time, let’s answer the question: How did it function and feel? Let’s check it out. 

Let’s Talk Specs

The barrel length of this rifle measured 20 inches. It has an A2 pattern stock that gives it a classic M16 feel. It shipped to with Magpul backup irons sights, so we ran it with those for our testing. An optic or a nice set of iron sights is ideal, but this fit our needs.

The FN-15 MD Heavy Barrel has the classic feel of an M16. (Photo: April Robinson/

Internally, this FN-15 features a traditional Mil-Spec trigger. FN gives the trigger weight a range of 4.75 pounds to 7.75 pounds. It provided a very clean breakpoint with little uptake. It also had the iconic audible reset when releasing the trigger. 

The overall weight for this FN-15 was approximately 8.2 pounds. That said, it would be closer to 10 pounds with a loaded 30-round magazine and an optic.  Speaking of magazines, it uses any AR-15 pattern magazine: polymer, steel, or aluminum. It makes no difference. For our tests, we had two 30-round polymer ProMags and one 10-round Magpul Pmag. 

Related: FN Factory Tour to see How M240s, SCARs, and 509s are Born

Range Time


The FN-15 functioned flawlessly. (Photo: April Robinson/

Due to the 2020 ammo situation, we were only able to put 250-300 rounds through the FN-15. We used Federal XM855 62 grain FMJ “Green Tip” ammunition. 

We tested it from multiple shooting positions, and it ran flawlessly. We maintained groups of 2 to 3 inches at 100 yards. It was definitely me and the back up iron sights, not the rifle, that kept us from reaching 1 MOA precision.

The 20-inch barrel with an A2 rifle stock offers a stable shooting platform. It may be more unwieldy than an AR-15 patterned off the M4 carbine. But when it comes to accuracy at long range and mitigating recoil, the M16A2 features shine. This is especially true with rapid follow-up shots.  

Downsides of the FN-15?

If I had to give a downside to this rifle, it would be that this setup isn’t the ideal “general-purpose” AR-15. But … it wasn’t meant to be either. When it comes to real-world application, this platform is best suited for varmint hunting or long-range engagements, not close quarters. 

The heavy barrel of the FN-15 MD Heavy Barrel makes this rifle more suited for longer ranges. (Photo: April Robinson/

The plus side is FN makes a variety of FN-15s ranging from M16 collector variants to FDE FN-15 tactical carbines. Whatever you’re looking to get out of an AR-15, FN will deliver in spades.  


FN is renowned around the globe for its high-quality firearms, and even the U.S. military has relied on them for decades. The M249 SAW, M2 Browning .50 caliber machine gun, M240 machine gun, SCAR, and M16/M4 are all in current production by FN for the U.S. government. 

Having served in the U.S. Army and as a contractor afterward, I carried and shot the full spectrum of FN weaponry. I had the pleasure of experiencing everything from their “Ma Deuce” to the F2000. The models, designs, and applications varied greatly. But the quality always stood steadfast. 

The bottom line is this: You can’t go wrong with FN. Their firearms are meticulously crafted by some of the best in the business. FN is the real deal when it comes to making firearms and have been doing it for over 130 years.

If you are looking for a no joke AR-15 that is accurate, rugged, and reliable, the FN-15 is a worthy contender. The MSRP for a new FN-15 MD Heavy Barrel is $1,399.

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