FAXON DUTY SERIES LIGHT TAPERED 16" 9MM BLOWBACK AR15 BARREL

Rifle Barrels › Duty Series › 9mm › 16″ Light Taper, Blowback  |  Works with: 9mm BCG • 1/2x28 9mm muzzle devices • HUB adapter • 13″ handguard

Why a 16″ 9mm Carbine, and What Makes a PCC Barrel Different

A 9mm AR is a different machine from a 5.56 AR, and the barrel shows it. There is no gas system: the bolt is held closed by its own mass and a heavy buffer, and pushed open by the case, so the barrel has no port, no journal, and no gas block, only a taper from the receiver to the muzzle. There is no separate barrel extension either. Faxon turns the shank that fits the upper receiver directly into the barrel, presses a .125″ index pin into it so the barrel cannot rotate under the barrel nut, and cuts the chamber with a radiused, chamfered mouth that feeds from Glock- and Colt-pattern magazines without a ramp. Because the chamber is part of the barrel, length is measured from the breech face to the muzzle, and this barrel measures 16.4″ on the print, so it clears the 16″ rifle minimum with room to spare and no pinned device.

16″ is the 9mm length for a carbine: a rifle lower, a stock, no paperwork, and the sight radius and rail length for a PCC that shoots matches, sits by the door, or teaches someone to shoot a rifle on cheap ammunition and no recoil. The Light Taper profile is why this one does not feel like a 16″ barrel. A 9mm carbine does not need heat capacity; it needs to swing between targets and stay balanced with a heavy buffer and bolt in the back, so Faxon turns the body from .675″ to .625″ and the barrel weighs 1.34 lb, which owners notice first. Velocity is a footnote: 9mm gains most of what a longer barrel can give it in the first eight inches, so a 16″ is only 50 to 100 fps ahead of an 8.5″. If the gun is going on a pistol or SBR lower, the 8.5″ and 10.5″ are the same barrel shorter.

What “Duty Series” Means

Duty Series is Faxon’s 4150 CMV line: the M4/M16 barrel alloy, salt-bath QPQ nitrided inside and out. 4150 carries about 0.50% carbon plus vanadium, which gives it more strength and wear resistance than 4140, and nitride adds a hard, corrosion-resistant surface to the bore and exterior without plating anything, and it adds virtually nothing to the surface: a few ten-thousandths of an inch, roughly a tenth the width of a human hair. On a 9mm barrel, where the enemy is lead and copper fouling rather than heat, the hard, slick nitrided bore is the feature you notice: it shoots clean and cleans with a patch.

What’s in the Box

How It’s Made

Every Duty Series barrel is made start to finish in Faxon’s Greater Cincinnati plant, on Faxon’s machines, to Faxon’s prints. This is the routing for this barrel.

1. Drill and pull-ream 4150 CMV bar is gun-drilled, then pull-reamed from the chamber end to a .348″ bore held to ±.001″, with a 32 Ra maximum finish checked on a profilometer and a borescope pass for reamer marks.
2. Button rifle A carbide button is pulled through from the chamber end to form six grooves, right-hand, one turn in 10 inches, to a .355″ groove diameter. Bore and groove are air-gauged.
3. Stress relieve and qualify The rifled blank is stress relieved before it becomes a finished barrel, then the OD is qualified true to the bore so every later cut references the same axis.
4. Turn the receiver shank The breech end is turned to the .999″ shank that fits the upper receiver, held to within .0008″, with the 1.170″ barrel-nut shoulder behind it. This is the feature a 5.56 barrel gets from a separate extension; here it is part of the barrel.
5. Turn the taper and muzzle The body is turned from .675″ at the shoulder to .625″ at the muzzle, true to the bore, the .720″ muzzle shoulder is formed, and the 1/2x28 muzzle is threaded and crowned.
6. Chamber The 9mm chamber is cut and checked with a headspace gauge, the chamber mouth is radiused and chamfered for magazine feeding, and chamber surfaces are held to a 20 Ra finish.
7. MPI and nitride The machined barrel is 100% wet magnetic-particle inspected for surface and near-surface flaws, then salt-bath QPQ nitrided inside the bore and out, hardening the surface while adding virtually nothing to it.
8. Pin and mark After nitride, the .125″ index pin is pressed into the shank and the Faxon shield, order number, and “9 x 19 1-10T” are laser-engraved.

What Reviewers and Owners Say

Voted Favorite Aftermarket Barrel by Shooting Sports Retailer every year since 2022 — the Gold Award, the top honor in the category. Faxon also took the Tactical Retailer Gold Award in the same category in 2025. Here is what buyers have said about Faxon 9mm barrels and this one.

5.0 stars across 19 reviews on FaxonFirearms.com. Elsewhere: Faxon’s 9mm barrels average 4.7 stars across 33 reviews at OpticsPlanet and 5.0 across 11 at MidwayUSA, and this 16″ has owner reviews at Primary Arms.

Build It Out: Faxon Parts That Fit This Barrel

A 9mm AR needs fewer parts than a 5.56, and the ones it needs matter more. Everything below is made or specified to the same prints this barrel is.

Duty Series 16″ 9mm Blowback FAQs

Is this a 9mm Luger / 9x19 chamber? What about +P?

Yes: a SAAMI 9mm Luger (9x19) chamber, cut with a 9mm headspace gauge and marked 9 x 19 1-10T on the barrel. Standard and +P ammunition are fine; +P+ and 9mm Major are not SAAMI loads and are not recommended in a blowback gun.

Why is there no gas port?

Because a 9mm AR is a blowback gun. The bolt is not locked; it is held closed by the weight of the bolt carrier and buffer, and the case pushes it open after the bullet leaves. That is why the barrel has no port, journal, or gas block, and why the buffer and bolt weight matter so much in a 9mm build (see below).

Will it feed from Glock magazines? Colt magazines?

Both. The chamber mouth is cut with a radius and a wide chamfer instead of the M4-style feed ramps a 5.56 barrel gets from its extension, so rounds coming in from a Glock-pattern lower or a Colt-pattern lower both find the chamber. Faxon’s 9mm BCG is likewise cut for both patterns. The lower’s magazine well and feed geometry still matter; if a build nosedives rounds, look at the lower’s ramp before the barrel.

Does it use a standard AR barrel extension?

No. The extension is part of the barrel: the .999″ shank that fits the upper receiver, the barrel-nut shoulder, and the index pin are all machined into the same piece of 4150 CMV, and the pin is pressed in at Faxon. It drops into any mil-spec AR-15 upper with a standard barrel nut and any 9mm handguard, and it is not removable. The Faxon 9mm BCG is the matching bolt.

What bullet weights does the 1:10 twist stabilize?

All of them. 1:10 is the standard 9mm twist and handles 115, 124, and 147 gr, jacketed or coated, supersonic or subsonic. From a 16″ many 147 gr loads run transonic, so for a suppressed carbine pick a 147 gr load rated well under 1,050 fps.

What buffer and spring does a 9mm blowback need?

A heavy one. With no gas system, the buffer and bolt mass are what keep the breech closed long enough for pressure to drop. Most 9mm builds run a 5.5 to 8 oz 9mm buffer with a standard carbine spring; a dedicated 9mm lower may use its own. Faxon’s full-mass 9mm BCG has a removable carrier weight so you can tune reciprocating mass to the buffer you run. Start heavy; a light buffer in a blowback gun is hard on the bolt, the lower, and the shooter.

Is 16″ the overall length, and does it count as a rifle barrel?

Yes. The print calls for 16.405″ from the breech face to the muzzle, which is how barrel length is measured, so it clears the 16″ rifle minimum on its own with no pinned device. On a 9mm AR the chamber is part of the barrel rather than the extension, so about 1.1″ of the length is chamber and about 15.2″ is exposed ahead of the receiver face. Muzzle threads take the last .62″ and any 1/2x28 9mm device can be swapped freely.

What muzzle devices fit? Can I use a 5.56 device?

Any 1/2x28 device with a 9mm bore: Faxon’s MuzzLok 9mm flash hider, 9mm A2, or Plan B 9mm devices. Do not use a 5.56 device even though the threads match: a .223 bore will not pass a 9mm bullet. The threads are .62″ long, the AR standard, so rifle-pattern devices seat on the shoulder; devices made for .5″ pistol threads may bottom out and need a thread spacer.

Will it work with a suppressor?

Yes, with two notes. Use a fixed-barrel spacer or a direct-thread or fixed mount, not a recoil booster (Nielsen device), because the barrel does not move; and check the mount’s thread depth against the .62″ AR-length threads. Faxon’s 1/2x28 HUB adapter fits any HUB-pattern can. A 16″ 9mm is a quiet host; see the velocity FAQ on picking a 147 gr load that stays subsonic from a carbine.

How fast does 9mm leave a 16″ barrel, and will 147 gr stay subsonic?

About 1,350 to 1,400 fps with 124 gr, 1,400 to 1,450 with 115 gr, and 1,050 to 1,100 with 147 gr, depending on the load, or 50 to 100 fps more than an 8.5″. 9mm gains most of what a longer barrel can give it in the first eight inches, so the 16″ is a legal-length and sight-radius choice, not a velocity one. The thing to know for a suppressed carbine: many 147 gr loads that are subsonic from a pistol go transonic or supersonic from 16″, so pick a 147 gr load rated well under 1,050 fps or accept a little crack.

Can I build this on a rifle lower? A pistol lower?

A rifle lower, yes, with a stock and no NFA paperwork: the barrel is over 16″ on its own. It also works on a pistol or SBR lower, though there is little reason to pay for a stamp on a 16″ barrel. Check your state law on overall length and features before you buy. Faxon cannot advise on your specific configuration.

Why a 16″ 9mm instead of an 8.5″ or 10.5″?

Because it is a rifle. A 16″ goes on a rifle lower with a stock, needs no stamp or brace, and gives the sight radius and rail length a PCC wants for matches and for teaching new shooters. It gives up almost nothing in the trade: 9mm does not need the length for velocity, and at 1.34 lb the Light Taper 16″ weighs about what a heavy-profile 10.5″ does. The short barrels are for a gun that has to be short; the 16″ is for a gun that has to be simple.

What does 4150 CMV mean, and is the nitride inside the bore?

Chrome-moly-vanadium steel with about 0.50% carbon, the M4/M16 barrel alloy, which gives it more strength and wear resistance than 4140. Salt-bath QPQ nitride is a diffusion treatment, not a plating, so it hardens the bore and the exterior without changing the rifled dimensions Faxon air-gauges before treatment, and it gives the barrel its corrosion resistance and matte black finish. On a 9mm, where lead and copper fouling are the enemy, a hard, slick nitrided bore cleans with a patch.

Where is it made, and what is the warranty?

Made in Greater Cincinnati, Ohio, from bar stock to finished barrel, and covered by the Faxon Lifetime Guarantee.

Dimensions are from the Faxon engineering print and inspection sheets for this SKU; weight is nominal. BCG, buffer, and muzzle device sold separately. Owner reviews are quoted as written from FaxonFirearms.com and dealer product reviews; press quotes link to their sources. Award: Shooting Sports Retailer Choice Awards, Favorite Aftermarket Barrel, Gold. Covered by the Faxon Lifetime Guarantee.