The .45-70 Government cartridge, a venerable round with a rich history, boasts impressive stopping power and enduring popularity among both collectors and shooters. Understanding its dimensions is crucial for safe handling, proper reloading, and selecting appropriate firearms. This guide provides a comprehensive overview of the .45-70's key measurements and specifications.
Key Dimensions of the .45-70 Cartridge
The .45-70's dimensions aren't standardized across all manufacturers and ammunition types, leading to some slight variations. However, the following represent typical measurements:
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Case Length: Approximately 2.105 inches (53.5 mm). This is a critical dimension, as it determines compatibility with different firearms. Slight variations exist depending on the manufacturer and type of ammunition (e.g., loaded vs. empty case).
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Bullet Diameter: .458 inches (11.63 mm). This is the diameter of the projectile. It's important to note that the bore diameter of .45-70 rifles is slightly larger to accommodate the bullet's expansion upon firing.
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Rim Diameter: Approximately .510 inches (12.95 mm). This is the diameter of the cartridge's rim, crucial for proper feeding and extraction in lever-action and other types of rifles.
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Overall Length: This varies depending on the bullet length, but generally falls between 2.5 inches (63.5 mm) and 3.2 inches (81.3 mm) depending on the bullet type and manufacturer.
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Case Head Diameter: This is the diameter of the base of the cartridge. While not always precisely specified in commercial literature, it is important for firearm compatibility. It usually measures approximately 0.510 inch (13 mm).
Understanding Variations in .45-70 Dimensions
The seemingly simple dimensions above conceal nuances that experienced shooters and reloaders appreciate. These subtle variations stem from several factors:
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Manufacturer Differences: Different ammunition manufacturers may have slight tolerances in their production processes, resulting in minor variations in case length, head diameter, and other dimensions.
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Bullet Type: The use of different bullet weights and profiles (round nose, flat nose, pointed) significantly impacts the cartridge's overall length. Heavier bullets naturally increase the overall length.
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Case Condition: Fired cases may exhibit slight dimensional changes compared to new cases due to expansion and contraction during firing.
Importance of Accurate Measurements
Precise knowledge of .45-70 cartridge dimensions is critical for several reasons:
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Firearm Compatibility: Using ammunition with incorrect dimensions in a given firearm can lead to malfunctions, jams, and potential damage to the weapon. Always consult your firearm's manual for specifications on compatible ammunition.
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Safe Reloading: Accurate measurements are paramount for safe and effective reloading. Incorrectly sized cases or bullets can result in dangerous pressure increases, potentially causing catastrophic failure.
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Accuracy: Even slight variations in dimensions can affect bullet seating depth and overall accuracy.
Conclusion
The .45-70 cartridge, while powerful and historic, demands respect and careful attention to detail. Understanding its dimensions and the subtle variations that exist is crucial for safe handling, proper reloading, and ensuring optimal performance in your firearm. Always prioritize safety and consult your firearm's manual before handling or loading ammunition.
