Georgia-based Liberty Suppressors spent years doing research on what it takes to produce the best-possible integrally suppressed AR-15 upper receiver for the popular 5.56 NATO cartridge. Using primarily off-the-shelf parts to avoid getting bogged down in the limitations of proprietary components, the company finally released a tuned upper receiver in 2019: the Zulu Integral 5.56 NATO Upper Receiver.
In the initial development stages of the Liberty Suppressors Zulu upper receiver, company engineers focused on a set of key criteria that had to be examined for optimized performance. These key elements involved, of course, sound mitigation, management of back pressure, bolt-carrier velocity, noise from the ejection port, baffle erosion and overall accuracy. Ultimately, the company aimed to provide a balance between all these elements for a well-built, solidly performing component designed for use on any standard AR-15.
The final design of the Liberty Suppressors Zulu started with a basic railed upper receiver made by Aero Precision. Mated to the receiver is an Odin Works custom-made barrel combined with Liberty's own integral suppressor system and heat shield. Inside the receiver, consumers will find a tuned St. Croix Tactical bolt-carrier group, and the entire barrel-and-suppressor assembly is surrounded by an Aero Precision handguard. The stainless-steel barrel, rifled with a 1:8-inch twist rate, is built with a .223 Wylde chamber, which allows users to take advantage of precision-made .223 Rem. match ammo while also shooting hotter 5.56 NATO.
The integrally suppressed portion of the gun is built with a Grade 5 titanium baffle system, complete with a blast baffle made from Inconel 718 for added durability. The overall length of the barrel is 10.5 inches, and the suppressed portion of the assembly is pinned and welded to bring the entire barrel-and-suppressor component to a non-NFA length of 16.6 inches. This ensures that consumers only need one tax stamp to purchase the receiver. The entire upper-receiver assembly weighs 3 pounds, 11 ounces, and the suggested retail price on the unit is $1,550. All NFA rules apply.