Loading 300 Blk - ep 19 - Crimp Tests with jacketed bullets

Published on April 16, 2016
Duration: 39:04

This video demonstrates how to set up and use the Lee Factory Crimp Die for 300 Blackout ammunition. The instructor details a method for establishing repeatable crimp settings by marking the die and press, allowing for light, medium, and heavy crimps. Testing reveals that while extreme crimps can distort bullets, a medium to heavy crimp is generally effective for preventing bullet setback without significantly degrading accuracy or brass longevity.

Quick Summary

For 300 Blackout reloads, a medium to heavy crimp is recommended to prevent bullet setback in semi-automatic actions. Testing with a Lee Factory Crimp Die showed that while heavy crimps are generally effective, excessive crimping can degrade accuracy, particularly with certain bullet types like the 147gr FMJ. A repeatable setting, achieved by marking the die and press, is key to consistent results.

Chapters

  1. 00:01Introduction to 300 Blackout Crimp Tests
  2. 00:12Ammo Preparation and Crimp Die Introduction
  3. 01:04Bullet Types and Load Data Overview
  4. 01:14125gr SST Load Details
  5. 01:31147gr FMJ Bullet Introduction and Cost
  6. 02:07Subsonic Goal with 147gr Bullets
  7. 02:48147gr Subsonic Load Data
  8. 03:00168gr A-Max Load Details
  9. 03:14220gr Hornady ELDX Load Details
  10. 03:32Challenges with Lee Factory Crimp Die Settings
  11. 04:00Setting Up the Crimp Die on the Press
  12. 04:45Finding Maximum Crimp Setting
  13. 06:10Finding Minimum Crimp Setting
  14. 06:47Establishing Crimp Adjustment Range
  15. 08:03Marking Crimp Settings for Repeatability
  16. 09:17Testing Crimp Settings with 147gr Bullets
  17. 10:14Observing Crimp Effects on Case Mouths
  18. 11:03Visual Inspection of Crimp Levels
  19. 12:37Evaluating Heavy Crimp Appearance
  20. 13:38Comparison with Factory Ammo Crimp
  21. 14:33Selecting Final Crimp Settings for Testing
  22. 15:01Applying Final Crimp Settings
  23. 15:14Crimping 125gr SSTs
  24. 15:33Crimping 147gr FMJs
  25. 15:47Crimping 168gr A-Max (No Cannelure)
  26. 16:40Adjusting Crimp Settings Between Stages
  27. 17:11Identifying Optimal Crimp Mark
  28. 17:48Desired Heavy Crimp Characteristics
  29. 18:20Testing Point of Impact Difference (147gr vs 220gr)
  30. 19:49Crimp Effects on 168gr A-Max and 220gr ELDX
  31. 21:23Preparing for Live Fire Testing
  32. 21:43Firearm Setup for Testing
  33. 21:54Testing 125gr SSTs (Light to Heavy Crimp)
  34. 23:57Testing 168gr A-Maxes (Light to Heavy Crimp)
  35. 27:23Testing 220gr ELDX Subsonics (Light to Heavy Crimp)
  36. 29:27Testing 147gr FMJ Subsonics (Light to Heavy Crimp)
  37. 31:42Collecting Targets and Initial Observations
  38. 31:59Analyzing 125gr SST Group Results
  39. 32:44Analyzing 168gr A-Max Group Results
  40. 34:07Analyzing 220gr ELDX Subsonic Group Results
  41. 35:04Analyzing 147gr FMJ Subsonic Group Results
  42. 36:40Reasons for Crimping Ammunition
  43. 37:33Optimal Medium Crimp Characteristics
  44. 38:26Conclusion and Final Thoughts

Frequently Asked Questions

How do you set up a Lee Factory Crimp Die for 300 Blackout?

To set up a Lee Factory Crimp Die, remove the lock ring, screw the die into the press until it touches the shell holder, then raise the ram and screw the die down until the collets begin to engage. Mark this maximum setting, then back the die out one full turn for the minimum. Mark intermediate points for repeatable light, medium, and heavy crimps.

What is the purpose of crimping 300 Blackout ammunition?

Crimping 300 Blackout ammunition, especially for AR-15 platforms, helps prevent bullet setback. Bullet setback occurs when recoil causes the bullet to be pushed deeper into the case, which can increase pressure and lead to inconsistent performance or safety issues.

Does crimping affect the accuracy of 300 Blackout reloads?

Crimping can affect accuracy. While a medium to heavy crimp is generally beneficial for preventing setback, excessively heavy crimps can distort bullets, as seen with the 147gr FMJ in this test, leading to significantly larger groups. Light crimps may also result in poor accuracy for some bullet types.

What is the recommended crimp level for 300 Blackout reloads?

Based on testing, a medium to heavy crimp is generally recommended for 300 Blackout. The instructor found a setting about an eighth of a turn back from maximum cam-over on the Lee Factory Crimp Die to be ideal, providing a distinct crimp without damaging the brass or bullet.

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