Part 6: The Best Survival Carbine (AR Style Rifle)

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By Joel Jefferson •  6 min read

Part Six: (Commercially available Gas Piston Systems) There are fewer choices for Gas Piston Systems compared to DI/DGI but if you are looking for a Gas Piston Driven AR-15 Survival Carbine, these 8 manufacturers will get you started. 

This article is Part 6 in a series of posts.
Read Part 1: (A Little Background)
Read Part 2: (History)
Read Part 3: (Direct Gas Impingement (DI/DGI) vs. Gas Piston Operated)
Read Part 4: (Build Options)
Read Part 5: (Commercially Available DI/DGI Direct Gas Impingement Systems)

Gas Piston Systems


Has established a great reputation as of late for their gas piston rifles, both for Lwrc-Survival-Carbine-Riflereliability and customer service. The DEA has also recently approved their rifle system for purchase by their agents. They have a number of interesting and innovative products on their website.

“LWRC International, LLC provides reliable, accurate, and durable tools for the Warfighter, law enforcement officer and civilian shooter. Through innovative design, disciplined engineering, and the use of state-of-the-art manufacturing processes and materials technologies, our products are tailored to fulfill the mission of the end user.” –


Offers a unique system featuring the ability to do a quick barrel change to a differentLewis Machine and Tool Survival Rifle caliber round or to switch between a DI/DGI system to a gas piston system.

“In response to the growing demand for quick-change barrel systems, Karl Lewis, President of LMT, designed the Monolithic Rail Platform. The MRP™ upper receiver is a one-piece lightweight upper receiver with an integral forend. Mil-Std 1913 rails run from front to the forend on each of the four sides. The MRP™ receiver comes in two different lengths, one traditional rifle and the other for Close Quarter Battle (CQB).  With four rails, the MRP™ system offers plenty of places for accessories such as optics and lights. “ –


Patriot Ordnance Factory, this company has been building piston AR rifles for awhile and has received very positive reviews by their clients.  They are exclusively used by the Phoenix Police Department’s Special Assignments Unit.

“One of the major differences between the (POF) and any other is the patented gas system that eliminates the inherent problems associated with Stoner’s original design. The original AR direct impingement gas system not only blows large amounts of fouling and particulate matter back into the receiver, but also causes excessive heat to be transferred to the receiver area in rapid semi-automatic or full-automatic fire.”  Bottom line, when you talk with people who know rifles, they know POF.


Primary Weapons Systems started by making top of the line flash suppressing compensators. They recently started making gas piston driven AR rifles using a unique design based on the mechanics and design of the AK-47.

This is different than the other gas piston rifles on the market in that it is a single piece long stroke piston that absorbs the gas to cycle the bolt (which it is attached to), this reduces the recoil, eliminates many parts that typically break and wear out in other systems (i.e. springs and spring cups), and effectively eliminates many of the problems associated with carrier tilt. They also offer a 7.62×39 mm AR (Mk107 Diablo) which works on a standard MilSpec AR lower. I personally will be looking forward to an opportunity to check out their system more closely in the future.

“The PWS proprietary operating system utilizes an operating rod that is attached to the carrier and a floating head piston that is attached to the operating rod. Our product improvements have addressed reliability and performance issues as well as reduced carrier tilt, cam pin wear and carrier bounce. The MK1 series is built to be a true combat carbine. With no unnecessary gas adjustments and only one moving assembly, this is the most rugged, simple and versatile piston operating system available.” –

Heckler & Koch

You can’t really have a list of survival rifles without mentioning HK.  HK Survival CarbineWith a slogan like “In a World of Compromise, Some Don’t” you get the feeling that these Germans know how to make rifles and guess what…..they do.

Buying an HK is sort of like buying a BMW, they are not cheap but at the end of the day you know that someone did not cut corners on your survival rifle. The words “Quality” and “Reliability” are not just punchlines in a sales pitch for HK, they are backed up by the respect of gun enthusiast all over the world. I can testify that the HK416 is a very nice rifle that I have carried it in the field. The civilian version called the MR556A1 due out in 2011, looks to be cut from the same cloth.

Fabrique National

Better known as FN. “Early 2004, United States Special Operations Survival-Rifle-Survival-CarbineCommand (USSOCOM) issued a solicitation for a family of Special Forces Combat Assault Rifles, the so-called SCAR, designed around two different calibers but featuring high commonality of parts and identical ergonomics.”

Although the FN SCAR does not qualify as a AR-15 due to its non AR-15 mil-spec lower, it is a piston driven AR style survival rifle that might fall into the category of you either love it or hate it. One thing is for sure, FN is a quality manufacturer.


For the more cost conscious customer, Ruger has entered the piston driven black rifle market with the SR-556. This rifle comes with some after market components such as Troy Battle Sights and Magpul Magazines.

“The chrome-lined gas block and chrome-plated piston and regulator work together to provide a smooth power delivery stroke to the bolt carrier. The by-products of the gas system are vented out the bottom of the gas block, away from the bolt carrier, keeping the action clean and free from contaminants. The end result is significantly improved performance over gas driven rifles.” –


Makes a high quality build using the tops parts available on the market.  Uses the PWS rifle system as their standard for the upper receiver (see #3 above). For more information on this system check out the following video where the system is broken down and analyzed by a customer, click here: –

Conversion Kits

If you are sitting at home wishing you had a piston driven AR-15 to replace your old DI/DGI AR-15, you do have some choices short of buying a new AR-15 survival rifle.  There are several companies who make conversion kits including Adams Arms, Osprey Defense, Addax Tactical, and Bushmaster.  To see a list and review of more of these kits click here.

Continue Reading Part 7: Ammo

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Joel Jefferson

Joel is one of the original founders of After college, he joined the USMC where he served as an (0302) Marine Infantry Officer. Joel is an avid outdoorsman and spends much of his free time in the mountains. Joel’s hobby is researching survival gear & weapons as well as prepping. Read his full interview here.