FN America Factory Tour Columbia South Carolina : FN15



On my way to Big 3 East I got to go on a fantastic tour of the FN America factory in Columbia, South Carolina. The South Carolina Factory is where they make the new FN15 AR-15 rifle. It is also the same plant that makes the military issue M4 and M16. They also make the FNS and FNX line of pistols as well as belt fed machine guns. But that is for another article. Kristina Demilt, Public Relations and Marketing Sr Specialist, and JP Reconnu, FN15 Product Manager, took us through the manufacturing process of the FN15 rifle.



They get casted receivers and machine them in South Carolina.


Casted Upper Receivers.

Notice that the lower already has the markings engraved into the side.


Casted Lower Receiver


There are multiple CNC machines to machine out the receivers. They make them in batches then inspected and logged by the operator before moving onto the next process of manufacturing.


When the receivers are finished being machined, 30 random receivers are pulled out of 125 units and independently inspected for tolerances. If the receiver is slightly over sized then they can go back and adjust the CNC and machine more material. If the receiver is too small in areas, then it is recycled.

Aside from receiver machining the barrels are made in another section of the factory. They receive steel rods and load them into a machine to be deep hole drilled. The machine is completely automatic other than having to load the barrel hopper to feed the machine.


The rods are drilled out four at a time in just 10 minutes before the next four rods are drilled.

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At this stage, the barrels have a plug shoved inside to smooth out the reaming marks.



This is the brass plug.


Then the barrels are cold hammer forged in one of three machines. As the machine hammers the outside of the barrel, a rifling die is being pushed through the barrel. So the hammering forms the rifling around the insert.

The Hammer weighs about 40 lbs


In the photo below you can see the bronze hammers. As the center revolves, the T-shapped hammers are compressed by the rollers in the other circumference.


Photo of the cold hammer forge machine


The Cold Hammer.


Size of the hammer.


Below you can see the barrel before and after cold hammer forging. As it hammers the barrel, the barrel increases in length.


Before and after the cold hammer forging.

The cold hammer forging is not limited to just the military grade weapons. FN America also uses this process to make their pistol barrels and machine gun barrels.

The barrels are heat treated and then machined. See the bare spot in the middle? They clamp the barrel there and at the end to cut the profile of the barrel. If they did not hold it by the middle, the barrel would warp as it is machined.





As always every step in the manufacturing process is checked for tolerances.



This machine uses lasers to scan the barrel profile and sends that information to a computer to display the dimensions of this particular barrel. The computer will let the machinist know if any part of the barrel profile is out of spec.

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Here is are the racks for chrome lining the barrels.


After their rifle and machine gun barrels are chrome lined. They get sent to assembly.

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Here this woman is bending the barrel to correct a slight curve in the barrel. She checks the roundness of the barrel with a few gauges.


Once all the receivers are completed and barrel assemblies are completed, the rifle is assembled. Each rifle is function checked before it leaves the factory. They produce about 3500 weapons a month.


Here are some extremely short .300blk barrels.


JP shows us an unreleased .300blk FN-15 pistol.



Below is the lower of a LE/MIL select fire FN16.



Here is the Commemorative FN15. The markings match the govt issued M4 and M16.



After the tour we broke for lunch and then they took us to the Engineering Range to test some of their FN15 rifles.


This is the DMR FN15. I really enjoyed this rifle as the light weight rail felt very well balanced. Below that is the Commemorative M4A1 FN15. The M16 and M4 FN15s are built exactly the same as the issued military rifles. Obviously there are some changes like the M4 has a 16″ barrel and they both are not select fire. The sights and receivers are made exactly the same. The Issued M4 and M16 have a seam line from the original casting mold. To replicate the M4 and M16 they left these mold lines on the Commemorative edition FN15s.



The FN Blue competition FN15 rifle is the top of the FN15 line. They are using a Mega Arms upper. This was built with 3gun competitors in mind. Both the DMR and Competition come with Timney triggers.



There is more to come. Next up: Machine Guns.

Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at nicholas.c@staff.thefirearmblog.com


  • Tyler McCommon

    I’ve been looking at getting the full length FN15 (20in M16A4 clone). Honestly the $950 street price isn’t bad and from what I’ve seen their parts are of exceptional quality.

  • David

    Did they ever fix the Safe/Fire/Auto engravings on their military collector rifles? Lazy. Either they were using old lowers and just adding the auto, or wouldn’t take the time to change ‘fire’ to ‘semi’.

    • ostiariusalpha

      It’s a bit fuzzy, but the Collectors edition lower receiver in the picture definitely has SAFE/SEMI/AUTO markings.

    • Jay

      Hahaha. Calling FN lazy. You are funy. Tell me what other company developed so many successful military firearms, and in the same time don’t have a stick up their ass when dealing with civilians?

  • MPWS

    Receivers are not “casted” but forged. Look at witness flash lines.

    • Pat

      Yeah, I was wondering about that too…

    • Anton Gray Basson

      Drop forgings perhaps?

      • MPWS

        Correct, into mold (die); one stroke and done. Then sheer off the outcropping.

    • ostiariusalpha

      A lot of the technical terms are a bit off in this article. For instance, that’s a mandrel in the bore when they cold-hammer forge the barrels, not a die. Oh well, I just came for the pretty pictures.

    • Giolli Joker

      And casted isn’t even a word. ☺

      • Daisuke0222

        The content of the article is interesting, but it’s rife with spelling, usage and grammar errors. It reads like the first draft of a middle-school student’s field trip essay. Frankly I expect better from TFB.

  • Ed

    Cool. You can buy a FN AR-15A4 and a FN M-forgery and then get a FN lower and find a FN A2 upper make a AR-15A2 you got a whole FN weapons family of Stoner weapons. All except the M-16A1 which FN never made.

  • Adam D.

    Freaking awesome post! Thanks a lot!
    I’m very interested in the engineering and manufacturing part of the firearms industry,
    but it’s not easy finding stuff like this.
    More please!

  • Patrick the Canadian

    They seem to be using a lot of Midwest Industries handguards…

  • FN Herstal is probably the best of the gun producers in the world. Such notable gun makers as John Browning and Dieudome Saive produced some of the finest gun in the world. The Browning High Power and many of Browning’s auto load shotguns comes to mind.

  • Geoff

    All that engineering and technology yet they use government profiles on them – the most retarded and inefficient profile in existence – thin where it should be thick, and thick where it can be thin.

  • buzzman1

    I took the tour in the Mid 80’s when I was stationed at Ft Jackson.