Primary Weapons Systems UXR Barrel Conversion Kit, .300 AAC Blackout, 14.5-Inch

The Primary Weapons Systems UXR Barrel Conversion Kit swaps an existing UXR upper to .300 AAC Blackout with a 14.5-inch barrel.

Key Specifications

• Chambered in .300 AAC Blackout.
• Measures 14.5 inches in barrel length.
• Rifled with a 1-6 twist rate.
• Sold under Primary Weapons Systems’ UXR modular platform.
• Sold as a conversion kit — barrel and related components to change an existing UXR upper’s caliber, not a complete upper or receiver.
• Ships without a serialized lower receiver, since it is a barrel-focused component kit rather than a complete firearm.
• Classified as a firearm part/accessory, not a regulated firearm itself — no FFL transfer required to purchase.

Frequently Asked Questions

Does a barrel under 16 inches make this a regulated short-barreled rifle? By itself this is a firearm part/accessory, not a complete firearm, and it ships without NFA paperwork. However, federal law treats a rifle with a barrel under 16 inches and a shoulder stock as a regulated short-barreled rifle (SBR) that requires ATF Form 1/Form 4 registration and a tax stamp before assembly. Building on a pistol-configured lower with an arm brace, or otherwise keeping the host firearm outside the rifle/SBR definition, are common ways builders stay compliant — confirm your specific configuration with the ATF or a knowledgeable gunsmith before assembling this barrel onto a host firearm.

What does this conversion kit include? It’s sold as a barrel-based conversion kit for switching an existing PWS UXR upper to .300 AAC Blackout, rather than a complete upper or receiver.

What twist rate does this barrel use? It’s rifled with a 1-6 twist, suited to a range of .300 AAC Blackout bullet weights including heavier subsonic loads.

Buy the Primary Weapons Systems UXR Barrel Conversion Kit, .300 AAC Blackout, 14.5-Inch

Order the Primary Weapons Systems UXR Barrel Conversion Kit, .300 AAC Blackout, 14.5-Inch today for fast, insured shipping from a Lubbock, TX gun shop. Browse more Primary Weapons Systems parts in our gun parts category.