Colt Advanced Piston Carbine (APC): Meet Colt’s New Piston-Driven HK416 Killer

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By David Crane
defrev at gmail dot com

October 13, 2008

The Colt SCW (Sub-Compact Weapon) isn’t the only potential "HK416 Killer" (a.k.a. "416 Killer, for short) in Colt’s new product arsenal, or the only new Colt Defense weapon offering shown at the 2008 AUSA Meeting & Exposition. Colt Defense is also now offering the Colt Advanced Piston Carbine (APC) 5.56x45mm NATO (5.56mm NATO)/.223 Rem. select-fire carbine/subcarbine/SBR, which leverages research and development, and capitalizes on lessons learned, from the Colt M5 and Colt LE1020 gas piston/op-rod-driven carbines. The Colt APC piston-driven carbine/SBR is perhaps Colt’s most direct threat to the HK 416, as, save for the APC’s Mil-Std-1913 "Picatinny" Monolithic Upper Receiver, the APC is the closest of all Colt’s new products to the 416 in terms of weapon configuration, operation, and appearance.

Unlike the HK416, however, the Colt APC piston-driven carbine/SBR utilizes Colt’s proprietary Articulating-Link Piston (ALP) operating system and gas regulator sleeve, both of which DefenseReview covered in our previous article on the Colt SCW. However, we’ll go through them again, quickly, here. According to Colt, the Articulating Link Piston operating system…

reduces operating stresses inherent in other piston system designs, enhances/improves weapon accuracy, and eases removal of the piston and op rod (operating rod) for routine weapon cleaning and maintenance. Defense Review could elaborate on how the ALP system accomplishes this, but we won’t, as we haven’t received clearance to do so, yet. The hardened Gas Regulator Sleeve a.k.a. Gas Impingement Sleeve that fits over the piston system increases the APC’s reliability, durability and longevity by maintaining a lower cyclic rate/ROF and reducing wear on major components. This correspondingly reduces weapon life cycle costs. Again, DefenseReview could go into greater detail on how this component accomplishes what it does, but we won’t, at least not until we’re cleared to do so.

The APC’s Monolithic Upper Receiver offers an integral Mil-Std-1913 "Picatinny" (quad) rail system/forend rail tube that lowers overall weapon weight and cost, and aids in zero retention for optics, lasers, etc.

The end-user can get an APC with either a Button-Rifled or Cold Hammer Forged Barrel, either of which is capable of 15,000+ rounds before replacement, and they can stick Colt’s new Folding/Flip-Up Titanium Front Sight/BUIS (optional) on it if they want a lighter-weight sight that reduces weight on the barrel and therefore improves accuracy and zero retention even further. This lightweight flip-up titanium front sight/BUIS was originally designed and developed for Colt’s SCAR candidate weapon.

The APC’s Modified Bolt Carrier features a solid gas key and rear skids for enhanced strength, reliability and durability under heavy firing. Following this theme of increased strength and durability is the new Cam Pin Protector that eliminates damage to the upper receiver cam pin slot that’s inherent in competing piston-driven systems.

Weapon reliability is enhanced by Colt’s new "Pivot Forward Design" Extractor, which increases the hold/grip on the cartridge case during hard extraction and full-auto fire. A reliable and durable extractor is obviously a crucial component, as this has traditionally been a weak point for the M4/M4A1 Carbine.

A new patent-pending Enhanced Dust Cover "Wiper" automatically covers the APC’s ejection port. This eliminates the need for a manual dust cover a.k.a. ejection port cover, except perhaps for a training situation where the user might want to walk around with a cleared weapon where the bolt carrier group is locked to the rear and the (traditional manual) ejection port cover is closed over the open ejection port to keep out foreign debris.

Finally, there’s an Optional Colt Grip Laser (CGL) vertical foregrip with integral white light and multi-mode visible laser (pulse mode and constant mode).

The Colt Advanced Piston Carbine is well-positioned to challenge the HK416 for dominance in the U.S. and global law enforcement and military (and hopefully, civilian tactical) markets, as, like HK 416, combines piston/op-rod operation with an M4/M4A1 Carbine-type configuration, including a multi-position collapsible/telescoping buttstock. The Colt APC is perhaps the HK416’s worst nightmare in this regard. Phil Hinckley, Executive Director of Quality and Engineering at Colt Defense LLC, assured me during my visit and firing session at Colt headquarters last month that the Articulating Link Piston operating system has been "bulletproofed" (my word) and is totally reliable under adverse conditions and high round count. If that’s true, and I have no reason to believe that it isn’t, why would anyone need an HK416, when the Colt APC offers the end-user a seemingly superior piston system? The articulating-link aspect should give the APC a reliability, durability and weapon-longevity advantage over the HK 416, if it’s as good as the Colt Defense team claims it to be.

I put a bunch of magazines through the Colt APC select-fire piston-driven carbine at one of Colt’s firing ranges, and the gun ran without a hitch. No stoppages or malfunctions. However, I haven’t run the APC under adverse conditions and high round count (thousands of rounds). Frankly, I’d like to see a head-to-head test between the Colt APC and HK416 in a test of this kind, and I’d really like to see 10.3", 11.5" an 12.5"-barreled APC SBRs outfitted with the FERFRANS Rate Reduction System (RRS) for CQB/CQC, vehicle deployment, and medium-range-engagement applications.  The RRS artificially lowers an AR-15 carbine or SBR’s cyclic rate/ROF under the 700 RPM threshold with, according to FERFRANS Specialties, no reliability deficit. The RRS accomplishes this by operating separately from (i.e. completely outside of) the weapon’s gas system. 

Author’s Note: Colt should definitely offer the APC to the civilian tactical shooting market, and I hope they do it soon.  Frankly, it would be nice if Colt started offering long guns to the civilian tactical shooting market again, period.  I’d also like to see the APC offered with the SCW’s side-folding/telescoping stock/Bolt Carrier Buffer System combo as an option.

Photo Credit: Colt Defense LLC

Company Contact Info:

Colt Defense LLC
547 New Park Ave
West Hartford, CT, 06110
800-241-2485 Toll Free
860-232-4489 Office
860-244-1442 Fax Website

Related Articles:

Colt Sub-Compact Weapon (SCW): Folding-Stock Tactical 5.56 SBR (Photos!)

Sources Sought: ‘Improved Carbine and Subcompact Individual Weapon System’

FERFRANS Gas Piston/Op-Rod SOAR Tactical AR-15 SBRs for Special Operations

FERFRANS Ultra-Concealable Piston-Driven 6-inch AR Subcarbine/SBR (Video!)

FERFRANS Combat Rifles and GRSC Combat Rifle Scope (CRS) at the Range

Acronyms and Abbreviations used in this article:

CQBR – Close Quarters Battle Receiver
CQB – Close Quarters Battle

CQC – Close Quarters Combat

SBR – Short Barreled Rifle

ROF – Rate of Fire
Op-Rod – Operating Rod

Full-Auto – Fully-Automatic
BUIS – Back-Up Iron Sight

Colt Advanced Piston Carbine (APC): Meet Colt’s New Piston-Driven HK416 Killer 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.

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