REVIEW: Superlative Arms Short Stroke Retrofit AR15 Piston System

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There’s been much said about AR15 gas system problems. Here’s another solution that really offers something different! READ MORE

superlative arms piston system

Major Pandemic

Over the last decade, piston driven AR systems have gained a lot of attention due to their ability to deliver cooler running reliability similar to the exceedingly reliable piston based AK platform. One of the many advantages of the AK platform has been its piston based operation which isolates operation gas pressures at the front to the gun away from the shooter and bolt and trigger group. This piston based system delivers a cooler and clearer running AK gun which arguably delivers more reliability. Some very bright folks figured out several ways to transfer that piston system over the the AR15 platform thus combining the accuracy of the AR15 platform with the reliability of the AK.

HISTORY
There have been a number of companies offering short and long stroke piston system. Long Stroke systems have the op rod attached to the bolt carrier such as AKs and Tavors. Op rods are not attached to the bolt carrier on short stroke systems. The main compromise between the two is that the Long Stroke system designs are typically heavier but inherently offer an integrated gas design that bleeds off excessive gases. The new Superlative Arms patented system extends this bleed off capability to a low profile Short Stroke system all while still providing gas pressure adjustment.

Let me first point out that Superlative Arms is the co-patent holder of the design offered by Syrac Ordnance and was also its manufacturing partner of the Syrac adjustable gas block and Piston system product line. Superlative could have been offering its own line of adjustable gas blocks and piston systems identical to Syrac’s however they developed their own unique patented gas bleed off design. Superlative’s bleed-off system is offered in both a direct impingement adjustable gas block and also in the co-patented short stroke low profile gas system. Though there are many similarities, Superlative Arms is on the market with their own systems.

superlative arms piston system
The super low profile block fits under virtually any handguard rail.

DESIGN
The Superlative Arms or piston system uses their patented bleed-off. Instead of limiting the gas pressure, this system functions more like a pressure regulator which limits the gas delivered to the gas tube or op rod piston and the rest of the excess gas is vented out the front of the gas block. Typical adjustable gas block systems have had some problems due to gas port and adjustment screw erosion from the captive excessive gas temperatures and pressures at the gas port. Many of us have seen this problem manifest themselves in wandering gas settings or even adjustment screw blowouts.

By porting and venting off that excessive high heat pressure the instant the pressure hits the gas block, the Superlative Arms system greatly reduces erosion and pressure based failure problems right at the gas block all while running cooler and cleaner for both their DI and piston systems. This bleed-off design in turn reduced the beating delivered to the adjustment mechanism and op rod.

Some previous short stroke piston systems have experienced problems with gas block durability and retempering of the op rod springs. In order to assure completely problem-free operation Superlative goes the extra mile and makes the piston block from melonited 416 stainless steel and uses a heat treated Inconel steel spring which is impervious to the pressures and heat generated by an AR15 even running in full auto. Superlative has accomplished this design feat all within a very small compact low profile design that is barely larger than most low profile gas block designs.

superlative arms
Unlike other adjustable systems which block gas, Superlative Arms bleeds it off. This results in a longer-lasting, less problematic solution. Unlike other adjustable systems which block gas, Superlative Arms bleeds it off. This results in a longer-lasting, less problematic solution.

INSTALLATION
Superlative Arms Direct Impingement (DI) adjustable bleed-off gas block is a simple swap for people who want to retain a DI based system. Pull off the old gas block, move the gas tube to the new Superlative gas block, reinstall, tune to assure reliable last round lock back and you done. Like all retrofit gas piston systems, the Superlative arms kit install is a bit more involved.

The Superlative Arms retrofit gas piston system includes everything a user would need for conversion of a existing AR15 including the gas block, op rod, op rod spring, and carrier. Any AR15 bolt can be used with their carrier. All the Superlative kits are all essentially the same with the exception of the pistol, carbine, mid, and rifle op rod lengths — just order the appropriate gas rod length specific kit..

First time installation requires some patience and about thirty minutes. Unlike a DI gas block install, the left/right and fore/aft alignment of the gas block is critical to reliable operation. With a stiff fixed op rod responsible for converting the blast inside the gas block to a shove on the carrier, it has to be free from any binding and also precisely the right length from the face of the carrier to the gas block.

superlative arms
An “AK-style” gas piston promises cooler and cleaner operation, and this did indeed deliver both!

The basic process is to install the gas block loosely on the barrel and insert the stripped op rod (minus the spring) into the gas block and tighten down the gas block piston plug. Then the task is to assure the op rod spins freely without binding with the carrier (minus bolt) fully seated in the upper receiver. If you have a fully seated carrier and freely spinning op rod then you can tighten down the gas block. If the carrier does not fully seat or the op rod does not spin freely, the gas block needs to be turned or moved out as appropriate. Of note the gas block should not be slammed right against the shoulder on the barrel — mine both required positioning the gas block off the shoulder of the barrel about 1/32-in.

Once those initial adjustments are made, the op rod is removed and then re-installed with the spring and the plug fully seated then backed out on-half turn. Similarly the carrier is removed and reinstalled complete with a bolt, cam pin, firing pin, and retaining pin. A final installation check is made to assure the carrier fully seats and positive hammer drop is achieved. All that is required now is to adjust the gas pressure in a process similar to any adjustable gas block.

This is a rise and repeat process of assuring the gas block sees just a bit more pressure than is required to offer a last round hold back of the carrier — generally one half turn pressure increase tuning over the lowest setting that will hold the bolt back.

superlative arms di
A more simple solution is one of Superlative Arms Direct Impingement type gas bleed off blocks. Outstanding quality!

FIT, FINISH, FEEL, FEATURES, & FUNCTIONS
If you are familiar with Syrac’s top notch gas block quality then you are already familiar with Superlative’s Manufacturing quality since they have been the manufacturer up to this point. The fit and finish is outstanding and the Ion Bond finish on the carrier and melonite on the block finishes are excellent.

Functionally the system offers a lot of advantages including being able to tune the pressure to just enough to drive the bolt carrier. The result is that there is less recoil, cooler running system, less carbon build up, and greatly reduced gas blowback on SBRs and AR15 pistols.

superlative arms
My two test guns: a Yankee Hill Machine rifle which was a test of the systems low pressure operation. Zero problems. The second build was a conversion of an Aero Precision and Phase 5 Tactical AR15 pistol build. AR15 pistols gas pressure are notoriously high. This was a test of how the Superlative Piston system would handle high pressure systems and it worked flawlessly!

FINAL THOUGHTS
Only a 1000 or so rounds in, I am impressed. Both offer something that is different than anything on the market, and a design which potentially offer greatly expanded durability over traditional AR15 piston systems. I have said many times that an adjustable gas system is the best upgrade any AR owner can make — note due to the low pressure issues I do not recommend any adjustable gas system for 300 Blackout or 7.62×39 AR15 builds.

Find all the parts you need to build your AR at Midsouth Shooters Supply! Click Here to Shop Now!

See more HERE and view all the SPECS

MSRP: $289

Major Pandemic

[Major Pandemic is an editor at large who loves everything about shooting, hunting, the outdoors, and all those lifesaving little survival related products. His goal is simple, tell a good story in the form of a truthful review all while having fun. He contributes content to a wide variety of print and digital magazines and newsletters for companies and manufacturers throughout the industry with content exposure to over 2M readers monthly. Click HERE to learn more.]

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