
Availability: In Stock
The RCBS Precision Micrometer for .338 Win Mag is a cartridge measurement tool built for reloaders who demand repeatable precision. Whether you're developing loads for long-range hunting, tactical shooting, or precision rifle competition, this micrometer lets you measure critical dimensions to 0.001-inch accuracy—the level of control that separates safe, consistent ammunition from guesswork. It takes just a few twists to dial in your measurements and verify your work.
Brass life and load safety both depend on knowing your actual dimensions, not assumptions. This micrometer measures from the datum point on the case shoulder to the base, giving you the same reference plane that SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) uses to define safe chamber and load specs. That means your readings translate directly to real-world rifle chamber conditions, eliminating the interpretation gaps that plague less rigorous measurement methods.
Chamber headspace and bullet seating depth are the two variables that most directly affect brass longevity and round-to-round consistency. By measuring both to 0.001-inch resolution, you can dial in your .338 Win Mag loads with confidence—verifying that your brass fits your chamber within safe limits and that your bullets seat at exactly the depth your rifle needs. That attention to detail is what separates a handful of reliable shots from ammunition that won't chamber or that risks pressure spikes.
If you're serious about reloading .338 Win Mag ammunition—whether for hunting magnum game at distance or pursuing precision rifle accuracy—this micrometer is the tool that closes the gap between intent and reality.
| Brand | RCBS |
| Product Type | Precision Micrometer |
| Caliber | .338 Win Mag |
| Measurement Resolution | 0.001 inch |
| Measurement Reference | Datum point on case shoulder to base |
The RCBS Precision Micrometer measures chamber headspace and bullet seating depth from the datum point on the case shoulder to the base. This gives you SAAMI-standard reference readings that match your rifle's chamber specs.
Precision ammunition starts with precision dimensions. Measuring to 0.001-inch tolerance lets you verify that your brass fits your chamber safely and that your bullets seat at the exact depth your rifle needs. That level of control supports both safety and brass longevity.
Yes, this micrometer is calibrated for .338 Win Mag cartridges. RCBS produces precision micrometers for other calibers as well.
Instead of assuming your dimensions are correct, this tool lets you measure them directly. Knowing your actual headspace and seating depth helps you develop loads that are safe, consistent, and that get the longest life out of your brass.

SKU: 167524850 • Width: 4.5in • Height: 1.9in • Depth: 5.95in • Weight: 0.7oz





Availability: In Stock
The RCBS Precision Micrometer for .338 Win Mag is a cartridge measurement tool built for reloaders who demand repeatable precision. Whether you're developing loads for long-range hunting, tactical shooting, or precision rifle competition, this micrometer lets you measure critical dimensions to 0.001-inch accuracy—the level of control that separates safe, consistent ammunition from guesswork. It takes just a few twists to dial in your measurements and verify your work.
Brass life and load safety both depend on knowing your actual dimensions, not assumptions. This micrometer measures from the datum point on the case shoulder to the base, giving you the same reference plane that SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) uses to define safe chamber and load specs. That means your readings translate directly to real-world rifle chamber conditions, eliminating the interpretation gaps that plague less rigorous measurement methods.
Chamber headspace and bullet seating depth are the two variables that most directly affect brass longevity and round-to-round consistency. By measuring both to 0.001-inch resolution, you can dial in your .338 Win Mag loads with confidence—verifying that your brass fits your chamber within safe limits and that your bullets seat at exactly the depth your rifle needs. That attention to detail is what separates a handful of reliable shots from ammunition that won't chamber or that risks pressure spikes.
If you're serious about reloading .338 Win Mag ammunition—whether for hunting magnum game at distance or pursuing precision rifle accuracy—this micrometer is the tool that closes the gap between intent and reality.
| Brand | RCBS |
| Product Type | Precision Micrometer |
| Caliber | .338 Win Mag |
| Measurement Resolution | 0.001 inch |
| Measurement Reference | Datum point on case shoulder to base |
The RCBS Precision Micrometer measures chamber headspace and bullet seating depth from the datum point on the case shoulder to the base. This gives you SAAMI-standard reference readings that match your rifle's chamber specs.
Precision ammunition starts with precision dimensions. Measuring to 0.001-inch tolerance lets you verify that your brass fits your chamber safely and that your bullets seat at the exact depth your rifle needs. That level of control supports both safety and brass longevity.
Yes, this micrometer is calibrated for .338 Win Mag cartridges. RCBS produces precision micrometers for other calibers as well.
Instead of assuming your dimensions are correct, this tool lets you measure them directly. Knowing your actual headspace and seating depth helps you develop loads that are safe, consistent, and that get the longest life out of your brass.
SKU: 167524850 • Width: 4.5in • Height: 1.9in • Depth: 5.95in • Weight: 0.7oz
