True Precision Stainless Steel 3.9" Threaded Barrel for Sig P320 Compact 9mm Luger (1/2"-28)

The True Precision Stainless Steel 3.9" Threaded Barrel for Sig P320 Compact is a precision-engineered drop-in replacement built for shooters who want better accuracy and the flexibility of a threaded muzzle. Machined from 416R stainless steel and made entirely in the USA, this 9mm barrel fits the P320 Compact, M18, and most X-Carry models, making it a smart upgrade for P320 owners looking to run suppressors or compensators without swapping hardware.

What sets this barrel apart is True Precision's proprietary broach cut rifling design—a 6-groove, 1/10 right-hand twist engineered to shoot all ammo types safely, including cast lead rounds. The SAAMI-spec chamber and 11-degree competition-style target crown deliver the accuracy potential you're paying for, while improved radii and chamfers mean better fit than stock without fussy fitting. Installation is straightforward; the drop-in design keeps gunsmithing out of the equation for most users, though minor fitting may be needed on some X-Carry variants. The included Viton high-heat integral O-ring lock thread protector keeps your threads protected when running naked, and the barrel retains the loaded chamber indicator cut found on M18 models, preserving interchangeability across P320 variants.

At 4.64" from breechface to muzzle (not counting the protector), this is a genuine compact-length barrel—short enough for everyday carry, long enough to deliver the velocity and dwell time the 9mm cartridge needs. Made to tighter tolerances than factory, it's the kind of upgrade that improves both reliability and shot-to-shot consistency. Whether you're building a suppressor-ready carry gun or a match-grade range pistol, this barrel punches above its weight.

Key Features

• Drop-in design fits P320 Compact, M18, and most X-Carry models
• Threaded 1/2"-28 with included high-heat Viton O-ring lock protector
• Proprietary 6-groove broach cut rifling (1/10 RH twist) for accuracy and reliability with all ammo types, including cast lead
• SAAMI-spec chamber with 11-degree competition target crown
• 100% USA-designed and manufactured from certified 416R stainless steel
• Improved fit over OEM with enhanced radii and chamfers
• Retains loaded chamber indicator cut for M18 interchangeability

Specifications

Frequently Asked Questions

Will this barrel fit my Sig P320 variant?

This barrel is designed as a drop-in for the P320 Compact and M18. Most X-Carry models will accept it, though minor fitting may be required on some X-Carry guns. It will not fit the X-Compact.

Can I shoot lead or cast ammunition through this barrel?

Yes. The proprietary 6-groove broach cut rifling is specifically designed to safely shoot all ammo types, including cast lead rounds.

What's included in the package?

The barrel ships with a Viton high-heat integral O-ring lock thread protector to secure your threads when not running a suppressor or muzzle device.

How much gunsmithing is needed for installation?

The barrel is a drop-in design and should install without tools or fitting for most P320 Compact and M18 users. Minor fitting may be necessary on some X-Carry models, though this is uncommon.