Silencerco AC859 Threaded Barrel for Sig P226 - 1/2x28 Thread Pitch

The SilencerCo AC859 threaded barrel for Sig P226 is a drop-in replacement designed to convert your full-size P226 to suppressed fire. Chambered in 9x19mm and fitted with 1/2×28 muzzle threads, this barrel accepts most common suppressors built for the P226 platform. It's machined to factory specifications, so installation is straightforward—no gunsmithing required. If you're running a suppressor-ready setup or planning to go that route, this barrel simplifies the transition while maintaining the reliability and accuracy the P226 is known for.

Built from 416R stainless steel and finished in a non-reflective black nitride coating, the AC859 is made to withstand the demands of suppressed shooting. The 4.5-inch length matches the standard P226 full-size frame, and the 1-10 inch right-hand rifling twist is optimized for the 9mm cartridge across a broad range of loads and bullet weights.

Whether you're a suppressor enthusiast looking to tame muzzle report or you simply want the flexibility to run a can when the time comes, this barrel gives you that capability without replacing the entire pistol. It's a practical upgrade for shooters who already trust the P226 platform and want to keep shooting one.

Key Features

• Drop-in replacement barrel—no gunsmithing or special tools required for installation
• 1/2×28 muzzle threads compatible with most P226-rated suppressors
• 416R stainless steel with black nitride finish for durability and corrosion resistance
• 1-10 inch RH rifling optimized for 9x19mm ballistics
• Machined to factory P226 specifications for reliable function and accuracy
• Fits standard 4.5-inch Sig P226 full-size frame

Specifications

Caliber	9x19mm
Muzzle Thread Pitch	1/2×28
Barrel Length	4.5 inches
Rifling Twist	1-10 inch (right-hand)
Material	416R Stainless Steel
Finish	Black Nitride
Firearm Compatibility	Sig P226 (full-size, 9x19mm)

Frequently Asked Questions

Will this barrel fit my Sig P226?

Yes, this is a direct replacement for the P226 full-size frame chambered in 9x19mm with a standard 4.5-inch barrel. Installation is straightforward—it's machined to factory P226 specs and drops in without modification.

What suppressors work with the 1/2×28 threads?

The 1/2×28 thread pitch is one of the most common muzzle thread standards for 9mm suppressors. Most popular P226-rated sound suppressors will be compatible, but always verify with your specific suppressor manufacturer before purchase.

Do I need a gunsmith to install this barrel?

No. The AC859 is designed as a drop-in replacement. Standard P226 field-stripping and reassembly procedures apply—no special tools or gunsmithing expertise required.

What's the rifling twist, and why does it matter?

The AC859 features a 1-10 inch right-hand twist, which is standard for 9x19mm and provides stable ballistics across the full range of 9mm loads, from subsonic to full-power rounds.