Butt Kickin' 5.56 Bullets - ep5 - 70gr Hornady GMX and CFE 223

Published on October 26, 2016
Duration: 19:41

This video details a reloading and ballistics test of 70-grain Hornady GMX bullets in 5.56x45mm NATO using CFE 223 powder. The instructor, Johnny, aims to achieve higher velocities than previously tested with Varget. While excellent velocities and consistent standard deviations were recorded, the accuracy (group sizes) was consistently poor across multiple charge weights, leading to further investigation into potential causes like brass quality.

Quick Summary

Reloading 70-grain Hornady GMX bullets with CFE 223 powder in 5.56x45mm NATO can achieve high velocities, with tested loads ranging from 2792 to 2903 ft/s. However, accuracy was poor, with groups exceeding 3 inches at 100 yards, leading to suspicion about brass quality.

Chapters

  1. 00:03Introduction: 70gr Hornady GMX & CFE 223
  2. 00:16Bullet Overview: 70gr Hornady GMX
  3. 00:50Powder Choice: CFE 223 vs Varget
  4. 01:29Reloading Data: Charge Weights
  5. 02:09Brass and Primers Used
  6. 03:24Charge Weighing and Initial Setup
  7. 04:32Case Capacity and Compression
  8. 06:34Range Time: CFE 223 Loads
  9. 06:55Accuracy Testing: 25.9 Grains
  10. 07:43Accuracy Testing: 26.2 Grains
  11. 09:30Best Group So Far & Disappointment
  12. 10:03Milk Jug Test Preparation
  13. 11:15Brass Inspection
  14. 11:39Accuracy Testing: 27.1 Grains
  15. 12:13Milk Jug Ballistics Test
  16. 13:32Bullet Fragment Recovery
  17. 14:10Recap: Disappointing Experience
  18. 14:38Group Size Analysis
  19. 14:52Velocity Data Analysis
  20. 15:19Viewer Feedback and Hypothesis
  21. 16:03Suspected Cause: PMC Brass Quality
  22. 16:30Future Testing: Brass Test
  23. 17:11Future Testing: Powder & Suppressor
  24. 18:39Upcoming Videos: Suppressor & MagnetoSpeed Test
  25. 19:34Conclusion and Next Steps

Frequently Asked Questions

What powder is recommended for high velocity with 70-grain Hornady GMX bullets?

CFE 223 powder is recommended for achieving high velocities with 70-grain Hornady GMX bullets in 5.56x45mm NATO. Data suggests it can push these bullets significantly faster than powders like Varget, with potential velocities exceeding 3500 ft/s.

What were the typical group sizes achieved with 70gr Hornady GMX and CFE 223 loads?

Despite achieving excellent velocities, the group sizes for the 70gr Hornady GMX loads with CFE 223 were consistently poor. Three out of five groups measured over 3 inches at 100 yards, with others around 2 inches, indicating significant accuracy issues.

What potential issues could cause poor accuracy with reloaded ammunition?

Poor accuracy in reloaded ammunition can stem from various factors. In this case, the instructor suspects the quality of PMC brass, specifically mentioning off-center flash holes, as a potential cause for the disappointing group sizes, despite good velocity.

What is the typical charge weight range for CFE 223 with 70gr Hornady GMX bullets?

The tested charge weight range for CFE 223 powder with 70-grain Hornady GMX bullets was from 23.6 grains up to a maximum of 27.1 grains, with loads developed in 0.3-grain increments for testing.

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