Hornady Sub-X .3115 255gr Subsonic Bullets - 100 Count

Subsonic rifle rounds demand bullets built for reliable expansion at low velocities, and the Hornady Sub-X .3115 255gr subsonic bullets are purpose-engineered for exactly that job. These 100-count rounds use a lead core with a gilding metal jacket, incorporating Hornady's patented Flex Tip technology to initiate controlled expansion reliably at speeds as low as 900 fps—ideal for suppressed rifles and subsonic handloads where maintaining velocity below the sound barrier is the whole point. Whether you're reloading for a bolt-action or semiautomatic platform, Sub-X bullets are built to function across a range of firearms and feeding systems.

The design centers on low-velocity reliability without sacrificing terminal performance. Long grooves running the jacket's length work with the flat profile and Flex Tip insert in the hollowpoint cavity to promote expansion at the velocity where most shooters run subsonic loads. Cannelures crimped into the jacket provide a positive grip for case crimping, a critical feature when loading for semiautomatics where bullet pull under cycling can be an issue. This attention to semiautomatic function makes Sub-X a practical choice for suppressed AR builds and other gas-system rifles.

Hornady designed Sub-X to meet FBI protocol standards for terminal ballistic testing, so you're not dealing with a gimmick—these are serious bullets engineered for consistent, controlled performance downrange. For reloaders building subsonic loads who want expansion they can count on, Sub-X removes the guesswork.

Key Features

• Patented Flex Tip insert promotes reliable expansion at velocities as low as 900 fps
• Lead core with gilding metal jacket and long grooves optimized for subsonic performance
• Cannelured design provides positive case crimp for semiautomatic reliability
• Flat bullet profile feeds reliably in a variety of firearms and feeding systems
• Meets FBI protocol terminal ballistic test requirements
• 100 bullets per box

Specifications

Caliber	.3115
Weight	255 grains
Quantity	100 count
Core Material	Lead
Jacket Material	Gilding metal
Recommended Minimum Velocity	900 fps

Frequently Asked Questions

Will Sub-X bullets work in my semiautomatic rifle?

Yes. Sub-X bullets are designed to feed and function reliably in a variety of firearms, including semiautomatic and gas-system guns. The flat profile and cannelured jacket support positive case crimping, making them well-suited for semiautomatics where feeding consistency matters.

At what velocity do Sub-X bullets expand?

Hornady's patented Flex Tip technology is designed to initiate controlled expansion at velocities as low as 900 fps, which is the core purpose of these subsonic bullets. This makes them ideal for suppressed rifle builds and subsonic handloads where maintaining subsonic speeds is a priority.

What comes in each box?

Each box contains 100 Sub-X bullets.

Are these bullets suitable for hunting?

Sub-X bullets are designed to meet FBI protocol for terminal ballistic testing and deliver controlled expansion at subsonic velocities. However, use and suitability for hunting depend on your specific application, local regulations, and rifle platform. Consult your jurisdiction's hunting regulations and load data before use.