Lyman H&i Sizing Die .312

• .312 sizing diameter: Brings cast bullets to a consistent .312 final size, which helps support uniform bore fit and more repeatable accuracy.
• Body sizing operation: Sizes the bullet body cleanly and consistently, making it easier to prepare cast bullets for lubrication and loading.
• Hardened steel construction: The steel die body stands up to repeated use and helps maintain dimensional consistency over long loading sessions.
• Tapered mouth design: Guides bullets into the die more smoothly, helping alignment and reducing the chance of distortion during sizing.
• Made in USA: Domestic manufacture and standard Lyman pattern fit make it a practical choice for established cast-bullet loading setups.

About the H&I Sizing Die Series

Lyman H&I Sizing Dies are part of the company’s long-established cast-bullet reloading range. These dies are intended for reloaders who cast their own bullets and need a simple, repeatable way to bring bullet diameter into the correct range before loading. In Lyman’s lineup, the H&I series works with the brand’s bullet sizing and lubricating equipment, giving handloaders a dedicated die for each target diameter rather than a one-size-fits-all approach.

The series is built around practical bullet preparation. Caliber-specific internal dimensions help the reloader match bullet size to the cartridge and barrel, while Lyman’s tapered mouth and hardened interior are designed to keep bullets aligned as they enter the die. That matters when working with cast bullets, where preserving a true cylindrical shape supports even lubrication, reliable chambering and consistent downrange results. For shooters focused on cast-bullet handgun or rifle loads, the H&I series remains a straightforward tool for controlling one of the key variables in bullet performance: final diameter.

About the Lyman H&i Sizing Die .312

The Lyman H&i Sizing Die .312 is a single body sizing die made for cast-bullet reloaders who need a precise .312 finished diameter. In practical terms, that makes it well suited to applications where bullet fit is critical to accuracy, clean bore performance and dependable loading. A properly sized cast bullet can help reduce variation from round to round, and it also supports more even lubrication before the bullet is seated.

This die uses a standard steel construction and follows Lyman’s established H&I pattern, giving it the durability needed for repeated use on the bench. The tapered entry helps start the bullet into the die with better alignment, which is important when sizing softer cast projectiles that can be damaged by poor entry or uneven pressure. Lyman also uses a hardened interior so the die maintains its working dimensions over time, helping the reloader produce bullets with a more consistent cylindrical form.

Because it is a single die, this model is a practical choice for reloaders who already know the exact diameter they want for a given cast-bullet load. Its standard 7/8"-14 thread compatibility also makes it easy to integrate into common reloading setups. For cast-bullet work, that combination of repeatable sizing, durable construction and straightforward compatibility is what makes this die useful on the loading bench.

About Lyman

The Lyman Gun Sight Company began in 1878 in Middlefield, Connecticut, and the brand remains closely tied to the shooting and reloading market. Lyman Products is headquartered in Middletown, Connecticut, and its core business centers on equipment and accessories for shooters and handloaders. The company’s range includes reloading dies, presses, bullet-casting equipment and gun sights, which gives it a long-standing presence in both ammunition preparation and sighting systems.

A key part of Lyman’s identity is continuity across product categories. Lyman acquired the Ideal reloading-tool business in 1925, strengthening its position in reloading equipment, and its sight products still reflect the principles behind William Lyman’s original sight design. That combination of historical gun-sight expertise and established reloading-tool production is especially relevant in products such as bullet sizing dies, where practical workshop design and repeatable results matter more than unnecessary complexity.

Main Features

• Manufacturer: Lyman
• Made in: USA
• Die operation: Body sizing
• Pack size: Single
• Die type: Standard
• Bushing: No
• Case type: Universal
• Sizing die material: Steel
• Material: Steel
• Adjustment: Standard
• Press compatibility: Standard 7/8"-14 thread
• Bullet diameter: 7.92 mm
• Bullet diameter: 312.00 inch

Warranty

2 years. This Lyman sizing die is covered by a 2-year warranty period.