San Tan Tactical®, Hornady Mfg®, and Proof Research® have partnered up on the San Tan new 6ARC rifles. San Tan’s innovative high-quality firearm systems and unparalleled performance in combination with Hornady’s New 6ARC round originally developed for a specialized group within the US DoD, and Proof Research premium carbon fiber barrels take the AR15 platform to a whole new level!
The Hornady 6ARC Round
Hornady Mfg® a leading ammunition manufacturer provides world-class performance in a 6ARC factory-loaded cartridge. The high-performance, match-accurate round features an excellent cartridge-to-chamber relationship and shoots exceptionally well. The 6ARC is commercially available in 108gr ELD-MATCH, 105gr BTHP BLACK, and 103gr ELD-X -Precision Hunter loads. The ELD-Match round boasts a G1.536BC.
6mm ARC Advanced Rifle Cartridge... Advanced. Versatile. Efficient. Effective.
Tested, selected, and fielded by a specialized group within the US DoD for its multi-purpose combat rifle program, the 6mm ARC is an extremely versatile cartridge that does everything much larger cartridges can, and everything that smaller cartridges can’t. Designed to meet the demanding needs of the world’s toughest critics, the 6mm ARC is a truly advanced cartridge capable of utilizing high BC, efficient 6mm bullets for unprecedented levels of performance from such a compact platform.

Advanced–Purpose-built to achieve performance never before delivered from the AR-15 platform by providing the ultimate blend of system weight, performance, and shootability. 

Versatile-Equally at home in AR-15 platforms and short or micro action bolt guns and suitable for a variety of applications from personal defense, match shooting, hunting as well as military and law enforcement use.

Efficient –Balanced application of cartridge and chamber geometry & interface, propellant design, and bullet selection for optimum performance and barrel life, the 6mm ARC has unmatched long-range performance from the AR-15 or micro action platform.

Effective–Excellent terminal performance from an assortment of bullet selections, for a variety of applications.
  • Features match accurate Hornady bullets that are held to the tightest tolerances in our test lab.
  • Low recoil
  • Flexible
  • Utilizes an efficient propellant charge and bullet weight combination.
  • Self-spot impacts on or off-target to make rapid adjustments.
  • Less felt recoil than larger short action-based (308 Win family) cartridges.
  • Factory ammunition offerings in a variety of bullet styles may be complemented by the handloader who has a multitude of 6mm bullets to choose from for specialized applications from varmint and deer hunting to match shooting needs
6mm ARC Load Data 

6mm ARC 108gr ELD-MATCH 
Muzzle Velocity = 2750FPSwith 24" test bbl
G1 BC = .536
SD = 261
Min Twist Rate = 1-8”
6mm ARC 105gr BTHP BLACK 
Muzzle Velocity = 2750FPSwith 24" test bbl
G1 BC = .530
SD = 254
Min Twist Rate = 1-8"
6mm ARC 103gr ELD-X -Precision Hunter 
Muzzle Velocity = 2800 FPS with 24" test bbl
G1 BC = .512
SD = 249
Min Twist Rate = 1-8
The Proof Research® 6ARC Carbon Fiber Barrel
The STT-15-6ARC and STT-15-6ARC-Lite both are configured with industry-leading Proof Research® Carbon fiber barrels. Known synonymously for their quality, ultra-lightweight characteristics, and superior accuracy. Featuring a 6ARC Chamber,18” Length, 7.5 Twist, Rifle gas, .750 diameter gas block.
The San Tan Tactical STT-15-6ARC rifles are a superb example of industry-leading technologies from companies pushing the envelope with a desire to achieve more! With the other wildcat caliber’s coming to market over the recent years, the recent 6.8 military requirement, all in an attempt to pursue the maximum output from the AR15 platform.
The Hornady 6 ARC cartridge combined with its variety of projectiles currently available allows a significant increase in capability above and beyond what is currently available in the AR15 platform. The capability to weight savings is seen in out STT-15-6ARC-Lite, the slick sided billet matched receiver set without signature lightning pillar cuts. Removing as much weight as possible without sacrificing strength and performance.
STT true matched pillar billet sets, hand-finished, matching serial numbers. The upper is cut from a single solid 7075T6 Certified Aerospace Aluminum. Propriety special burnished bore that gives a compacted internal surface, resulting in a much smoother surface finish. The bore, receiver extension face, barrel nut threads, and barrel extension surfaces are all machined in one operation ensuring that they are perfectly concentric and perpendicular to the barrel assembly.
STT Upper Features:
  • STT Truss Pockets for Increased Structural Rigidity
  • Cut from a Single Billet 7075 -T6 Aerospace Grade Aluminum
  • Shell Deflector
  • Fully Assembled with Forward Assist & Ejection Port Cover
  • Machined in T Markings for Easy Optic Relocation
  • Machined with M4 Feed Ramps
  • Machined to Mil-Spec Standards
  • Interfaces with all AR15/M16/M4  Systems & Accessories
  • Compatible with Multiple Rails, Anti-Rotation Tabs & Pins
  • Compatible with All Known Battery Levers 
  • No Roll Pin Design - Forward Assist Attaches Via Threaded Dowel Pin
STT Lower Features:
  • Huge 1.38” Integrally Machined Magazine Well Flare
  • Ambidextrous Quick Attach Detach Sling Swivel Points with
    Anti-Rotation Stops
  • Ambidextrous Bolt Release
  • Ambidextrous Magazine Release
  • Bullet Pictogram Safety Selector Markings
  • Set Screw Trigger Creep Adjustment
  • Set Screw Upper Take Down Tension Adjustment
  • Shooter Ready Finger Rest
  • Oversized Winter Trigger Guard Perfect for Gloved Hands
  • Dowel Screw Assembly
  • Ultra-Grip Texture on All Control
 San Tan Tactical STT-15-6ARC Rifle Features:
  • STT Suppressor Optimized Enhanced Bolt carrier group
  • STT 6 ARC HPT MPI Bolt, Crane O-ring Upgrade
  • Proof Research 18” Carbon Fiber 6ARC Barrel
  • CMC Triggers 3.5lb Single Stage Match Trigger
  • MagPul MOE plus Grip
  • MagPul CTR Stock
  • MagPul MBUS Pro
  • STT 15 16” MLOK Rail
  • Precision CNC machined from billet 7075-T6 certified aluminum
  • Propriety special burnished bore that gives a compacted internal surface, resulting in a much smoother surface finish
  • Type 3, class 2, deep black, hardcoat anodized black
  • Features extended feed ramps
  • Ambidextrous Mag and Bolt release controls (ambi version only not Lite)
  • CERAKOTE options are available for additional cost
At San Tan Tactical we want to leave a proud legacy of American Made firearm design. By innovation, superior performance, and value. American Made, through and through is the core value at San Tan Tactical. San Tan Tactical wants each and every shooter to be completely satisfied! Giving them absolute pride of ownership in each product we design and manufacture.
Our formula for success is simple-
San Tan Tactical believes in America and the heritage upon which this great nation was built! We are a company owned and operated by American’s for American’s! We only utilize the finest quality American made machines in conjunction with the highest quality American made materials. At San Tan Tactical we pride ourselves to give unparalleled customer service by, listening, understanding, and quickly satisfying our shooter's needs, desires, and/or concerns.
San Tan Tactical will never forget that our future success depends on the legacy of our past. We are not satisfied until you are satisfied!
All STT products come with a Lifetime Warranty and are made in the U.S.A., STT proudly designs all its products for Law Enforcement, Military, and Civilian use.
For more information about San Tan Tactical and all the products, we offer please visit us at