Hornady Sub-X Subsonic Expanding Bullets 338 cal .338" 307 gr SUB-X (338 ARC) 50/ct

Hornady Sub-X subsonic expanding bullets in 338 caliber are purpose-built for shooters who want effective terminal performance without the report. These 307-grain bullets are engineered specifically for subsonic applications—where velocity runs below the sound barrier—making them ideal for suppressed rifles, specialized hunting scenarios, or controlled-report shooting. Unlike standard hunting bullets that rely on velocity to expand, Sub-X ammunition uses Hornady's patented Flex Tip technology to initiate reliable expansion even at velocities as low as 900 fps, ensuring consistent performance downrange.

The construction centers on a lead core housed in a gilded metal jacket with long grooves that work in concert with the Flex Tip insert seated in the hollowpoint cavity. This design delivers deep penetration suitable for medium game in the 50–300 lb range. The cannelured jacket provides a positive case crimp, which is a critical feature for reliable feeding and function in semiautomatic firearms and gas system guns—a detail that matters if you're handloading for an AR or other modern platform. Whether you're developing loads for a suppressed 338 ARC or another 338-caliber rifle, these bullets meet FBI protocol standards for terminal ballistic performance, giving you confidence in their real-world capability.

Reloaders will appreciate the consistency and versatility of Sub-X ammunition. The 50-round count per box makes it easy to manage your handloading workflow, and the cannelure ensures case crimp reliability across different loading techniques. If you're building subsonic rifle loads and need bullets that expand predictably at low velocity, Sub-X delivers the ballistic behavior you're after without compromise.

Key Features

• Patented Flex Tip technology for reliable expansion below 900 fps
• Lead core with gilded metal jacket and grooved design for consistent penetration
• Cannelured jacket enables positive case crimp for semiautomatic reliability
• Meets FBI protocol for terminal ballistic performance
• Designed for medium game weighing 50–300 lbs
• Compatible with gas system firearms and a wide range of rifle platforms

Specifications

Frequently Asked Questions

Will Sub-X bullets expand reliably in my suppressed rifle?

Yes. Hornady designed Sub-X specifically for subsonic performance. The patented Flex Tip technology triggers expansion at velocities as low as 900 fps, which is typical for suppressed subsonic loads. They also meet FBI protocol standards for terminal ballistic testing, so you can trust their real-world performance.

Can I use these in a semiautomatic 338 ARC?

Yes. The cannelured jacket provides positive case crimp, making Sub-X suitable for reliable feeding and function in semiautomatic firearms and gas system guns, including modern AR platforms in 338 ARC.

What game are these bullets intended for?

Sub-X bullets are designed for medium game in the 50–300 lb range. The combination of deep penetration and reliable low-velocity expansion makes them effective for hunting applications within that class.

What comes in the box?

Each box contains 50 individual Sub-X bullets ready for handloading.