Lyman Pro Case Length Headspace Gauge 300 AAC Blackout

• Headspace and case-length check in one tool: The gauge verifies maximum and minimum cartridge headspace and also checks maximum case length, helping reloaders confirm resized .300 AAC Blackout brass before loading.
• Stainless steel construction: The corrosion-resistant stainless steel body stands up well to regular bench use and resists rust, so the gauge remains dependable over time.
• Non-roll body design: Flat sides keep the gauge from rolling across the bench, which makes setup work tidier and easier when adjusting sizing dies.
• Secure handling: The integrated O-rings provide a more positive, non-slip grip, making the gauge easier to pick up and handle with clean or lightly oily hands.
• Made for bottleneck rifle case setup: This model is intended for .300 AAC Blackout / 7.62x35mm brass, giving reloaders a simple way to confirm sizing results for safe, consistent ammunition assembly.

About the Pro Series

Lyman Pro reloading tools are built as upgraded bench tools for reloaders who want more than basic function from everyday measuring and case-prep equipment. Within the Lyman lineup, the Pro series sits above simpler utility tools by adding more refined machining, improved handling, and design details that make repetitive work easier at the loading bench. In the case of the Pro Headspace Gauges, that means a gauge made not only to check critical dimensions, but also to be easier to grip, harder to lose control of, and less likely to roll away while dies are being adjusted.

The series takes a practical approach to workshop ergonomics. Corrosion-resistant stainless steel supports long service life, while features such as flat exterior surfaces and grip-enhancing O-rings make the tools more convenient in day-to-day use. For reloaders working with bottleneck rifle cartridges, Pro gauges are intended to simplify die setup and dimensional checks without adding unnecessary complexity. The result is a line of measuring tools that focuses on repeatability, durability, and straightforward handling for serious handloading work.

About the Lyman Pro Case Length Headspace Gauge 300 AAC Blackout

The Lyman Pro Case Length Headspace Gauge 300 AAC Blackout is a caliber-specific reloading gauge made for checking resized .300 AAC Blackout / 7.62x35mm cases before they move on to priming, charging, and bullet seating. Its main job is practical: it helps confirm that brass falls within acceptable headspace limits and does not exceed maximum case length. That makes it especially useful when setting up or fine-tuning sizing dies, where small dimensional changes can affect chambering consistency and case life.

Unlike a basic gauge body, this Pro version adds handling features that matter on a busy loading bench. The stainless steel construction resists corrosion and wear, so it remains a dependable reference tool through repeated use. Flat sides keep it from rolling off the bench, which is a small but meaningful advantage during die adjustment sessions. The O-ring grip surfaces also make the gauge easier to handle securely, particularly when checking multiple cases in sequence.

For reloaders working specifically with .300 AAC Blackout, this gauge offers a straightforward way to monitor one of the most important stages of case preparation. By checking both maximum and minimum headspace as well as maximum case length, it supports more consistent ammunition assembly and helps identify brass that should be corrected or discarded before it reaches the rifle.

About Lyman

The Lyman Gun Sight Company began in 1878 in Middlefield, Connecticut, and the brand has long been associated with practical shooting and reloading equipment. Today, Lyman Products is headquartered in Middletown, Connecticut and focuses on tools and accessories for shooters and handloaders. Its range includes reloading dies, presses, bullet-casting equipment, and gun sights, reflecting a broad specialization in equipment used at the bench as well as on the firearm.

Lyman’s history in sight design remains part of its identity, and its tang and receiver sights still reflect principles from William Lyman’s original sight design. The company expanded its reloading presence when it acquired the Ideal reloading-tool business in 1925, helping establish the strong connection the brand now has with handloading tools. That long involvement in reloading equipment is directly relevant to products such as case gauges, where consistency, durability, and straightforward function matter most.

Main Features

• Manufacturer: Lyman
• Product type: Case length headspace gauge
• Compatible calibers: .300 BLK, 7.62x35mm, .300 AAC Blackout
• Material: Stainless Steel
• Color: Silver
• Application: Reloading

Warranty

2 years. Lyman states a 2-year warranty for this product, providing defined coverage for manufacturing defects under normal use.