STI Barrel, 5.5″ .45 Caliber with T1 Compensator

STI Barrel – 5.5″ .45 Caliber Short‑Chambered Barrel with T1 Compensator

STI builds some of the finest competition handguns in the world. Just as importantly, STI offers the same custom‑grade components so you can build or upgrade a pistol to match your exact needs. This 5.5″ short‑chambered .45 caliber STI barrel with T1 compensator is a perfect example of that commitment to quality.

First, STI machines this barrel from 416R rifle‑grade stainless steel billet forgings. This premium material delivers excellent strength, corrosion resistance, and long‑term dimensional stability. Because of this, the barrel maintains accuracy and consistency even under high round counts.

Next, STI gun drills the bore, then button rifles it for precision. After that, each barrel is air‑gauged to ensure exact internal dimensions. As a result, you get one of the most consistent and uniform bores available. The rifling features a 1:16 twist with six lands and grooves, which provides reliable accuracy with a wide range of .45 ACP and .45 Super loads.

To further enhance durability, STI vacuum heat treats and vacuum tempers the barrel to 40 Rockwell hardness. This process improves wear resistance while maintaining toughness. Then, STI machines the exterior to exacting tolerances for proper fit and alignment.

In addition, the barrel is short chambered. This allows a qualified gunsmith to finish the chamber precisely for your specific application. Because of this, the barrel works equally well for .45 ACP or as a high‑performance .45 Super compensator barrel when properly fitted.

The integrated T1 compensator helps reduce muzzle rise and improve control during rapid fire. As a result, shooters benefit from faster follow‑up shots and improved overall handling, especially in competition or high‑performance builds.

This barrel requires professional gunsmith fitting and is intended for experienced builders or custom pistol projects.

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Key Features

• Made from 416R rifle‑grade stainless steel

• Gun‑drilled, button‑rifled, and air‑gauged bore

• 1:16 twist, six lands and grooves

• Vacuum heat treated and tempered to 40 Rockwell

• Short‑chambered for custom chamber fitting

• Integrated T1 compensator

• Suitable for .45 ACP and .45 Super applications

• Designed for high‑accuracy and long service life

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Specifications

• Manufacturer: STI International

• Barrel Length: 5.5″

• Caliber: .45 ACP / .45 Super

• Material: Stainless Steel

• Finish: Stainless

• Firearm Type: Pistol

• Fits: 1911 / 2011 platforms

• Gunsmith Fitting Required: Yes