QUADRADYN ARMS // COMPONENT DOCKET [PUBLIC]
> OPENING BARREL MANIFEST ........ QMB-6
> LOADING LENGTH MODEL ........... 12.5 IN
> INSPECTION RECORD .............. READY
> PRODUCT CONSOLE ONLINE. T-0

6 ARC Barrel

12.5-inch 6mm ARC // Standalone component // Model QMB-6

The compact barrel architecture developed around the SARC-6 line, offered on its own. The QMB-6 combines a 12.5-inch suppressor-ready envelope, 1:7 twist, and a choice of precision stainless or hard-use chrome-moly vanadium (CMV) steel - each barrel released only after gauge-based dimensional verification.

From $274In stock // ships in 1–3 weeksModel QMB-6Ships direct where lawful
416R Stainless SteelHeavy profile // .936 gas journal // button rifled // precisionIn stock // ships in 1–3 weeks
Finish options // 416R Stainless Steel // base price $274
  • PolishedIncluded
  • Black Cerakote+$25
  • FDE Cerakote+$25
Choose finish at purchase
Buy now Spec readout

QMB-6 product views

MODEL // QMB-6
Quadradyn QMB-6 6mm ARC Barrel 416R Stainless Polished

The Quadradyn Standard

SEC.01
MODULE 01 // BALLISTICS
01 / THE 12.5-INCH ARGUMENT

Efficiency After the Muzzle.

Up until now, a compact 6mm ARC gives up some velocity to a longer barrel - even though it doesn't surrender the cartridge's high-BC advantage. But with Quadradyn's upcoming HIPR high pressure ammo, the game is about to change. Even without HIPR, this barrel is highly accurate at 650 yards and capable up to 800. With the release of HIPR-6 in 2027, we expect to be reaching confidently to 1,000+ in this exact 12.5-inch barrel.

Read the full analysis // FILE-004 in Intelligence
MODULE 02 // STEEL
02 / TWO STEELS, ONE PRINT

Choose the Role, Not the Steel.

Precision 416R stainless suits machining consistency; 4140 chrome-moly vanadium suits field use. Both share one chamber, twist, crown, and suppressor-interface geometry and take Black or FDE Cerakote. The polished, button-rifled stainless barrel is a heavy profile with a .936-inch gas journal for rigidity and less point-of-impact shift across a string (not rated for sustained rapid fire). With no gas-block dimple, it is ideal for a clamp-on gas block to maximize accuracy at range. The nitrided CMV barrel is a standard profile with a .750-inch journal and one set-screw dimple.

Same print // profile and steel selected by mission
MODULE 03 // QUALITY CONTROL
03 / GAUGED, NOT ASSUMED

Measure the Deciding Component.

Every barrel is verified for chamber and headspace, bore and groove consistency, crown geometry, gas interface, and muzzle-thread alignment before release. That is the same measurement-first discipline applied to every complete SARC-6, focused on the component that establishes the projectile's first conditions.

Dimensional release plan // gauge-verified before dispatch

Machining Sequence

SEC.02
STA.01 // STEEL

Choose the Blank

416R stainless or 4140 chrome-moly vanadium begins the same controlled print. The stainless blank is turned to a heavy profile with a .936-inch gas journal for rigidity, heat capacity, and less point-of-impact shift across a string; the CMV blank keeps the standard .750-inch journal for a lighter field barrel.

STA.02 // RIFLING

1:7, Stress-Relieved

Button rifling and thermal stress relief around a 1:7 twist. The faster twist stabilizes the heaviest 6mm projectiles, from the 103–108 grain low-drag class on up, without giving anything away at the lighter end.

STA.03 // CHAMBER

Concentric Chamber

The 6mm ARC chamber is built around bore-axis control, gauge-verified headspace, and an extended feed-ramp extension for the cartridge's wider case-head geometry.

STA.04 // MUZZLE

Crown & Threads

A recessed 11-degree crown and 5/8×24 suppressor-ready muzzle thread; thread alignment and crown geometry are part of final dimensional verification.

Spec Readout

SEC.03
QMB-6.SPEC_READOUT // PRODUCTION BUILD // 416R Stainless Steel

Purchase

SEC.04
PURCHASE.TERMINAL // QMB-6QMB6-SS
$274
416R Stainless Steel // Polished Included
Heavy profile // .936 gas journal // button rifled // precisionIn stock // ships in 1–3 weeks
Finish: Polished
The included finish follows the steel: polished on 416R stainless, nitrided on 4140 CMV. Black or FDE Cerakote adds $25.
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> NON-SERIALIZED COMPONENT // SHIPS DIRECT WHERE LAWFUL // IN STOCK // SHIPS IN 1–3 WEEKS

Shipping

Carrier, destination, signature, and jurisdiction policies are confirmed at checkout before any order is accepted.

Direct where lawful

Workmanship Coverage

Component coverage addresses defects in material and machining, and a 3 MOA change in accuracy before 4,000 rounds (416R stainless) or 13,000 rounds (4140 CMV); throat erosion past those counts and normal wear are consumable-life conditions.

Written warranty controls

Direct Support

Compatibility, installation-documentation, ammunition-selection, and function questions connect directly to Quadradyn.

Qualified installation recommended

Published Data

Dimensions, compatibility, velocity, dispersion protocol, and inspection criteria accompany the production specification.

Data before claims

Barrel length & shipping notice. The QMB-6 is a non-serialized 12.5-inch barrel and ships direct only where lawful. Some states and localities restrict the purchase, possession, or shipment of barrels shorter than 16 inches, and installing a barrel under 16 inches on a rifle-configured firearm creates a short-barreled rifle. Since October 9, 2026, the ATF no longer enforces the National Firearms Act's approval and registration requirements for short-barreled rifles, but many states still prohibit them or require them to be federally registered. Quadradyn does not ship barrels to jurisdictions where they are prohibited. The purchaser is responsible for confirming that the barrel, and the firearm it will be installed on, are lawful under all federal, state, and local law before ordering. QMB-6 barrels do not ship to California, Connecticut, the District of Columbia, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, New York, Rhode Island, Virginia, Washington, Puerto Rico, Guam, the U.S. Virgin Islands, American Samoa, the Northern Mariana Islands, or APO/FPO/DPO addresses. A barrel ordered together with a firearm ships with the firearm to your FFL dealer.