Barra Airguns 400e Polymer Barrel Kit

Upgrade the internal barrel of your 400e Gen 2 Polymer rifle with this complete barrel kit, available in your choice of Standard or Precision barrel type. This kit is specifically designed for compatibility with the 400e Gen 2 Polymer, which uses a 357mm barrel length.

The 400e Polymer first launched in October 2024 as part of the Gen 2 release. If you purchased your 400e Polymer between October 2024 and June 2025, your rifle came stock with a Precision barrel. If you purchased it in July 2025 or later, your rifle came with a Standard barrel. This is important to know when selecting the right kit for your goals.

• The Standard Barrel Kit offers reliable performance and allows for greater flexibility with BB types. It's less sensitive to slight imperfections in BB shape or finish, making it a great option for casual target shooting and higher-volume use with a broader range of steel BBs.

• The Precision Barrel Kit is built to tighter tolerances and delivers improved accuracy and consistency. If you're looking to push the limits of the 400e’s capabilities in terms of precision, this is your kit. However, because of its tighter internal specs, we strongly recommend using only Barra .177 Caliber / 4.5mm Zinc-Plated Steel BBs. These BBs are precisely machined and polished to perform reliably in the Precision barrel and prevent feeding issues.

Each kit includes all the necessary components to fully replace the barrel and install it correctly within your 400e Gen 2 Polymer. Whether you're upgrading from Standard to Precision or simply switching to match your ammo and shooting style, this kit gives your rifle a new level of performance and customization.