Mk 262 Cloning - pt 3 - Sierra vs Nosler with CFE223

Published on September 4, 2017
Duration: 26:43

This guide details the process of cloning Mk 262 Mod 1 ammunition using Hodgdon CFE223 powder, comparing Sierra 77gr MatchKing and Nosler 77gr Custom Competition bullets. It covers brass preparation, bullet seating with precise measurements, and range testing procedures. The instruction comes from an established subject matter expert in precision reloading, emphasizing methodical load development and data collection.

Quick Summary

Cloning Mk 262 Mod 1 ammunition involves using 77gr bullets (Sierra MatchKing or Nosler Custom Competition), Hodgdon CFE223 powder, CCI No. 41 primers, and Lake City brass. Expert reloading techniques, including precise seating depth measurement to the ogive and incremental powder charge work-up, are crucial for achieving sub-MOA accuracy and desired velocities.

Chapters

  1. 00:00Introduction to Mk 262 Cloning Part 3
  2. 01:00Sierra vs. Nosler Bullet Comparison
  3. 03:12Load Data and Components
  4. 04:23Brass Preparation and Resizing
  5. 07:11Seating and Crimping Process
  6. 13:22Range Testing: 23.8gr to 24.4gr
  7. 18:50Range Testing: 24.7gr to 25.0gr
  8. 22:27Post-Range Analysis and Conclusion

Frequently Asked Questions

What components are needed for cloning Mk 262 Mod 1 ammunition with CFE223 powder?

For cloning Mk 262 Mod 1, you'll need 77gr bullets (Sierra MatchKing or Nosler Custom Competition), Hodgdon CFE223 powder, CCI No. 41 primers, and Lake City brass. Proper reloading tools like a turret press, sizing die, comparator, and ammo checker are also essential.

How does CFE223 perform when reloading 77gr bullets for 5.56x45mm NATO?

Hodgdon CFE223 powder, when used with 77gr bullets like Sierra MatchKing or Nosler Custom Competition, can produce excellent accuracy. Loads tested ranged from 23.8gr to 25.0gr, achieving velocities around 2650-2690 fps with sub-MOA groups, though slightly below the target velocity for factory Mk 262.

What is the significance of measuring bullet seating depth to the ogive?

Measuring to the ogive using a bullet comparator is critical for consistent seating depth, especially with different bullet profiles. This ensures uniform chamber pressures and improved accuracy, as it accounts for variations in bullet shape that OAL alone might miss.

What were the key findings when comparing Sierra MatchKing and Nosler Custom Competition 77gr bullets?

While both bullets are suitable for Mk 262 cloning, the Sierra MatchKing 77gr HPBT demonstrated exceptional accuracy potential, producing a 0.226" group. Differences were noted in cannelure design and depth between the two bullet types.

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