Gunvira tries the BRN-9, a 5.5-inch self-contained direct blowback upper receiver in 9mm, manufactured by Matador Arms specifically for Brownells. Designed as a compact and lightweight "backpack gun," the unit features a simple, modular design with integrated M-LOK slots and a built-in absorber. Because the recoil system is entirely self-contained within the upper, it does not require a traditional buffer tube, allowing users to run the firearm with a folding stock or a Picatinny rear attachment for maximum portability.

According to her, one of the primary advantages of the BRN-9 is its extreme versatility across different AR-style lower receivers. She demonstrates that it can function with various configurations, including lowers designed for Glock, Scorpion, or Colt magazines. This adaptability is further highlighted through the use of Mean Arms mag adapters, which allow the upper to run 9mm ammunition through standard AR-15 PMAGs. Gunvira notes that while last-round bolt hold open can vary depending on the specific lower used, the system remains reliable across different ammunition types, including both steel and brass casings.

She says that this also positions the BRN-9 as a practical alternative to imported platforms like the Stribog, noting that the American-made upper is more compatible with standard AR accessories right out of the box. She specifically emphasizes its utility for night vision training, showcasing its performance during low-light shooting sessions with a suppressor.