SIG SAUER SIG556xi Modular, Multi-Caliber (5.56mm NATO, 300 AAC Blackout/300BLK, 7.62x39mm Russian) Gas Piston/Op-Rod Combat/Tactical Rifle/Carbine/SBR with Kalashnikov AK-47/AKM Configuration Capability!

Print Friendly, PDF & Email

By David Crane
david (at) defensereview (dot) com

All photo content contained in this article was shot by DefenseReview.com, and is copyrighted. DefenseReview.com owns the copyright on all photo content. All DR photos were shot with a Sony Cyber-shot RX100 (DSC-RX100/B) Digital Camera with 20.2 MP (20.2-megapixel) still camera and 1080p HD video camera capability.

The following article is property of DefenseReview.com (DR) and is copyrighted material. If you are reading this article on another website other than DefenseReview.com, please email us the website address/URL (where the unauthorized DR article reprint is located) at defrev (at) gmail (dot) com. Thank you.

February 25, 2014

The SIG P320 pistols weren't the only new SIG SAUER products DefenseReview (DR) handled and photographed at the company's booth at SHOT Show 2014. The following day, we got a chance to play around with the SIG556xi multi-caliber (5.56mm NATO, 7.62x39mm, and 300BLK) semi-auto-only gas piston/op-rod (push-type operating rod) combat/tactical rifle/carbine/SBR (Short Barreled Rifle) in 7.62x39mm Russian configuration (with buttstock removed), which essentially turns the weapon into a modernized 21st-Century Kalashnikov AK-47/AKM that utilizes AK mags–an we really liked it. In fact, it was one of the cooler things DR saw at the show.

The one we handled and photographed sported a TAPCO INTRAFUSE 30-round polymer AK mag (black), but it will take any MILSPEC 7.62x39mm AK mag out there, including the US PALM AK30 Mag 30rd AK mag. The same goes for 5.56mm mags in the 5.56mm and 300BLK configs. In our opinion, the SIG556xi's 7.62x39mm AK-config capability, as part of the weapon's multi-caliber aspect, is its primary selling point, as we aren't sold on the idea of a quick-change barrel system being a superior alternative, or even equal alternative, to the AR-15/AR-10's hot-swappable upper receiver modularity. Interesting and less expensive? Perhaps. But, superior? No.

Why not? Understand that any time you change barrel lengths or calibers on a quick-change barrel system gun like the SIG556xi, FN SCAR (MK 16 SCAR-L and MK 17 SCAR-H) and Beretta ARX-160, you're going to have to re-zero your optics and/or change optics, period. With the AR-15/AR-10 platform, you can pre-zero your optics for a specific upper receiver, barrel length and caliber, so when you swap uppers (and mags)–which takes all of about 30-seconds or less–you're ready to go fight or shoot, immediately. Sure an entire upper receiver assembly/optic combo is more expensive, but it's also more practical in the real world, whether you're running a gun at the range or in combat. It's (AR platform) faster and truly modular.

Don't get us wrong, QCB (Quick Change Barrel) systems are cool and all, but, in general, we still prefer the AR upper-swap system for small-caliber weapons from 5.56mm to 7.62x51mm calibers.

But, getting back to the SIG556xi multi-caliber tactical/combat carbine/SBR, we really like the way the weapon looked and felt in 7.62mm Russian Kalashnikov AKM-type config, and we're just sorry we didn't get a chance to fire it at SHOT Show Media Day at the Range 2014. Of course, we'd prefer to configure it with the optional MIL-STD-1913 "Picatinny" rail system/forend rail tube to complement the rail on the top of the upper receiver/receiver cover.

We also liked the SIG556xi's ambidextrous controls, the hot-swappable left-side/right-side charging handle, folding stock capability, and the nice-looking open-prong flash hider. We just hope it's pingless/ringless.

While we prefer the AR-15 platform in both direct-gas-impingement (DGI) an gas piston/op-rod (push-type operating rod) designs for 5.56mm NATO (5.56x45mm NATO) and 300 AAC Blackout (300BLK) calibers, where we can just swap uppers and loaded mags real quick, we wouldn't mind having a SIG 556xi in our collection, as well, especially since we can configure it like an AK–assuming the gun's a runner. It's just a nice, modular gun. Our one recommendation to SIG SAUER at the moment would be to develop a 5.45x39mm caliber conversion capability, since it's a great caliber that's accurate to longer range, easier to shoot, and less expensive than 7.62x39mm ammo. A 5.45mm Russian modular option (and perhaps also a 6.8 SPC conversion kit, as well) would really round out the package, in our opinion. It would seem logical that a select-fire version of the SIG556xi will be offered for MIL/LE end-users, but we forgot to ask about this, so we're not yet sure.

The following information on the SIG SAUER SIG556xi comes directly from the company's website:

"Introducing the SIG556xi, rewriting the standard for modularity, reliability, and performance for the modern rifle platform. Based on the legendary SG 550, the SIG556xi will change the way military, law enforcement, and responsible citizens look at adaptable rifles. Utilizing the time-tested rotating bolt and adjustable gas piston operating system, the SIG556xi allows operators a choice of caliber, barrel length, handguard/stock configurations and lower receivers.

A removable barrel allows the operator to select the necessary length for a given mission. Adding the appropriate bolt, the SIG556xi can be changed to any of three calibers, 5.56x45mm NATO, 300 Blackout, and 7.62x39mm NATO. Users can also quickly change out the non-serialized lower receiver, allowing the use of either AR-style STANAG magazines or rock-and-lock AK-style magazines. The SIG556xi upper receiver is the serialized part, making the lower an easy to purchase part.

Polymer handguards accept all Magpul® light and rail kits, while the aluminum and carbon fiber handguards accept 2”, 4”, and 6” M1913 rails. Barrels are available in 10”, 14.5”, and 16”. Truly ambidextrous, the SIG556xi features an ambi safety selector, magazine release and user swappable charging handle (right- or left-handed). Optional receiver end plates allow for the use of either AR receiver extension tubes and buttstocks or M1913 compatible stocks.

Thanks to a redesigned trigger package, the military and law enforcement versions of the SIG556xi are capable of full-auto fire in every caliber, including 7.62x39mm. The Russian lower has been thoroughly function tested with many available AK magazines, including US P.A.L.M."

Company Contact Info:

SIG SAUER, Inc.
18 Industrial Drive
Exeter, NH 03833
Phone: 603-772-2302
Fax: 603-772-9082
Law Enforcement Email: publicsafetysales@sigsauer.com
Military/Govt. Email: federal-militarysales@sigsauer.com
Website: http://www.sigsauer.com

TAPCO
P.O. Box 2408
Kennesaw, GA 30156-9138
Customer Service: 800-554-1445
Dealer: 800-250-3757
Fax: 800-226-1662
Local Phone: 770-425-1510
Customer Service Email: customerservice@tapco.com
Website: http://www.tapco.com

U.S. PALM
8360 E. Raintree Dr, Suite 201
Scottsdale, Arizona 85260
Phone: 480.398.3395
Fax: 480.398.3401
Email Info: info@uspalm.com
Website: http://uspalm.com

© Copyright 2014 DefenseReview.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without receiving permission and providing proper credit and appropriate links.

Related Articles:

SIG SAUER P320 Nitron Striker-Fired, Polymer-Frame Semi-Auto Combat/Tactical Pistol Series: Meet the SIG 320C (SIG 320 Carry/Compact) and SIG 320F (SIG 320 Full-Size) 9mm/.40 S&W/.357 SIG Pistols

SIG Sauer MCX (Mission-Configurable Weapon System) Dual-Piston/Op-Rod 5.56x45mm NATO and 7.62x39mm Russian AR-15 Short Barreled Rifle (SBR)/PDW/Carbine with Integral Suppressor Introduced at NDIA SOFIC 2013! (Photos!)

SIG MPX, MPX-C and MPX-K Multi-Caliber Submachine Gun (SMG)/Semi-Auto-Only Carbine/SBR Personal Defense Weapon (PDW) Packages with Silencer/Sound Suppressor, Lancer Systems Translucent Polymer Magazine and SIGTAC Reflex Sight/Combat Optic (Video!)

SIG Sauer SIG516 (5.56mm) and SIG716 (7.62mm) Short-Stroke Gas Piston/Op-Rod System Tactical AR Rifle/Carbine/SBR Series at SHOT Show 2010 (Photos!)

SIG 556 SWAT Gas-Piston-Driven Tactical Rifle/Carbine/Subcarbine

Latest-Gen Bad Company Tactical Rapid Retention System (BCT R2S) Combat/Tactical Weapons Holster/Mounting System and BCT Montesquieu Magazine Rack (MMR) Modular Rifle Mag Carrier/Pouch Rack for Combat/Tactical Pistols and AR-15 Carbine/SBR’s (Video!)

Condor Sentry Tactical Armor Plate Carrier Prototype: Lightweight Minimalist/Lo-Pro/Lo-Vis Tactical Body Armor/Tactical Vest with Fast-Adjustable Shoulder Straps and Side Straps

James Williams/CRKT Otanashi noh Ken Japanese Tanto Combat/Tactical Folder with Combo Edge and Aggressive Veff Serrations: 4.52″ Osoraku-Zukuri Tanto Blade Folding Knife for Deep Concealment/Concealed Carry (CCW) (Video!)

Adams Arms COR (Competition Optic Ready) 16.5″ Ultra Lite AR-15 Upper Receiver/Lightweight Tactical Gas Piston AR Carbine with HiperFire HiperTouch 24C Match Trigger and Diamondhead D-45 (Swing Sights) Integrated Sighting System Flip-Up BUIS for Tactical 3-Gun Competition Shooting (Video!)

DR Action Video!: DR Runs Adams Arms Evo Ultra-Lite (also written Ultralite) Mid-Length 16″ Piston AR Carbine Upper Receiver, SureFire MAG5-60 60-Shot Quad-Stack 5.56mm Rifle Magazine and Silver State Armory 5.56mm Ammo Through Mike Pannone/CTT-Solutions (CTT-S) Advanced Carbine Course

Adams Arms (AA) Tactical Evo Piston AR (AR-15/M16 Rifle / M4/M4A1 Carbine) Uppers (Upper Receivers) with Samson Evolution Rail System/Tactical Handguards for Martial Combat and Tactical Training (Videos!)

Adams Arms Gas Piston/Op-Rod Retrofit Kits for Tactical and Competition AR (AR-15)/M4/M4A1 Carbines/SBRs: Smooth-Shooting, Accurate, and Reliable (Photos and Video!)

Patriot Ordnance Factory POF P308 and P415 (also written P-308 and P-415) Gen-4 Tactical Gas Piston AR Rifle/Carbine/SBR’s with New E2 Chamber that Floats the Fired Case Right Out of the Gun (Video!)

Colt SWORD (Sniper Weapon and Observer Reconnaissance Devices) Networked Weapons Targeting System for Netcentric Warfare (Network-Centric Warfare) Demonstrated for DR at SHOT Show 2014 (Video!)

Desert Tech DT MDR (Micro Dynamic Rifle) Carbine 16″and MDR-C (Micro Dynamic Rifle-Compact) 10.5″ SBR Prototypes Introduced at SHOT Show 2014 (Video!)

Beretta ARX-160 (also written ARX160) Modular Assault Rifle/Carbine/SBR Demo Video and Interview Transcript from SOFIC 2011: Military Special Operations Forces (SOF), Law Enforcement Officers (LEO’s), and Civilian Tactical Shooters Get Tactical Rifle/Carbine with Ambi (Ambidextrous) Controls, Side-Switchable Charging Handle, and Quick-Change Barrel (QCB) System!

Remington ACR PDW SBR (Adaptive Combat Rifle Personal Defense Weapon Short Barreled Rifle) and Remington Individual Carbine (IC) Candidate: Remington Defense Assault Rifles/Carbines/PDWs at NDIA Joint Armaments Conference 2012 (Video!) DR Action Video! More FN SCAR PDW (Personal Defense Weapon) Prototype Live Fire Videos: Left-Side View Shows Reciprocating Charging Handle Cycling Back and Forth

LWRCI SIX8 M6.8-UCIW (Ultra-Compact Individual Weapon) 8.5″ 6.8 SPC Tactical Piston AR-15 SBR/PDW (Short Barreled Rifle/Personal Defense Weapon) and M6.8-A2 Piston AR Carbine with Fully-Ambidextrous Lower Receiver/Ambi Controls (Video!)

DR Exclusive Video: HK416C (also written HK 416C) “Ultra Compact Assault Rifle” SBR/PDW (Short Barreled Rifle/Personal Defense Weapon) Fired on Full-Auto at NDIA Infantry Small Arms Systems Symposium 2011 Range Day Shoot!

Chris Costa of Costa Ludus Hits the “Happy Switch” and Goes Full-Auto with the FERFRANS SOAR-P Select-Fire 5.56mm NATO/.223 Rem. Piston AR SBRs/Sub-Carbines/Carbines (Videos!)

Tactical AR-15/M4/M4A1 Carbine Aftermarket Accessories for Military Combat Applications: The Competition-to-Combat Crossover

Daniel Defense DD M4 Carbine ISR-300 Blackout (Integrally Suppressed Rifle 300BLK): DDM4v7-type 10.3″-Barreled Tactical AR-15 Short Barreled Rifle (SBR) (Video!)

Daniel Defense DDM4 v5-300 AAC Blackout (300BLK) 7.62x35mm Tactical AR-15 Carbine/SBR (Short Barreled Rifle): Serious Ballistics for Dynamic CQB/CQC and Engaging Targets out to 460 Meters!

Daniel Defense (DD) DDM4v7 (also written DDM4 v7) 10.3″ 5.56mm NATO/300 AAC Blackout (300BLK) DGI Tactical AR-15 SBR/Sub-Carbine with DD MFR 9.0 (Daniel Defense Modular Float Rail 9.0) for Military Special Operations Forces (SOF), Law Enforcement SWAT and Civilian Tactical Shooters! (Video!)

Daniel Defense DDM4v7 (also written DDM4 v7) Mid-Length Tactical AR Carbine/Rifle Outfitted with DD MFR 12.0 (Daniel Defense Modular Float Rail 12.0) Lightweight Modular Tactical Handguard/Rail System and Contour Gun Cam (Video Camera) System at SOFIC 2011 (Video!)

Primary Weapons Systems PWS MK110 MOD 1 10.75″ Tactical AR-15 SBR (Short Barreled Rifle): Mid-Length Gas Piston/Op-Rod 5.56mm NATO/.223 Rem AR for Suppressed Fire! (Video!)

PWS Diablo 7.62x39mm Russian: 7″-Barreled Long-Stroke Gas Piston/Op-Rod AR (AR-15) SBR/Complete Upper Receiver Assembly

PWS Diablo Long-Stroke Gas Piston/Op-Rod-Driven 5.56mm AR-15 SBR Upper Receiver

LMT MRP QCB Gas Piston/Op-Rod Carbines and SBRs in 5.56mm and 6.8mm

SIG SAUER SIG556xi Modular, Multi-Caliber (5.56mm NATO, 300 AAC Blackout/300BLK, 7.62x39mm Russian) Gas Piston/Op-Rod Combat/Tactical Rifle/Carbine/SBR with Kalashnikov AK-47/AKM Configuration Capability! by

About David Crane

David Crane started publishing online in 2001. Since that time, governments, military organizations, Special Operators (i.e. professional trigger pullers), agencies, and civilian tactical shooters the world over have come to depend on Defense Review as the authoritative source of news and information on "the latest and greatest" in the field of military defense and tactical technology and hardware, including tactical firearms, ammunition, equipment, gear, and training.

Check Also

Todd Jarrett Shows DR the New Staccato C 2011 Compact Combat/Tactical 9mm 1911 Pistol at SHOT Show 2024! (Videos!)

By David Crane david (at) defensereview (dot) com February 27, 2024 DefenseReview (DR) ran into …