300 Blackout - Loading for my SBR

Published on September 9, 2022
Duration: 25:34

This video details the process of reloading 300 Blackout ammunition for a Short Barreled Rifle (SBR). The instructor demonstrates brass preparation, powder charging with specific loads for both subsonic (Accurate No. 9 with 190gr Sub-X) and supersonic (Winchester 296 with 110gr V-Max) rounds, and bullet seating to precise overall lengths. It also covers initial range testing, chronographing velocities, and adjusting the SBR's gas system for reliable cycling, particularly with subsonic ammunition.

Quick Summary

Reloading 300 Blackout for an SBR involves selecting appropriate powders like Accurate No. 9 for subsonics and Winchester 296 for supers. Precise bullet seating to lengths like 2.070" for 190gr Sub-X and 2.050" for 110gr V-Max is crucial. Adjusting the gas block is vital for reliable cycling, particularly with subsonic ammunition.

Chapters

  1. 00:00Introduction: SBR Project Revival
  2. 00:16300 Blackout SBR Upper Assembly
  3. 00:46History with 300 Blackout Short Barrels
  4. 01:20Modest Goals: Sights and Functionality
  5. 01:35Bullet Selection: Subsonic vs. Supersonic
  6. 01:41Supersonic Load: 110gr V-Max with W296
  7. 01:56Subsonic Load: 190gr Hornady Sub-X
  8. 02:08Powder Choice: Accurate No. 9 for Subs
  9. 02:20Primer Selection: Federal AR Small Rifle Match
  10. 02:47Brass Selection: Gemtech Brass
  11. 03:28Brass Preparation: Lubrication and Drying
  12. 03:48Sizing Brass on Lyman Turret Press
  13. 04:28Bolt Fit Check
  14. 05:04Lee App Press Alternative
  15. 05:26Brass Trimming Issue
  16. 05:54Case Mouth Cleaning
  17. 06:10Priming with RCBS Universal Hand Priming Tool
  18. 06:31Brass Condition Issues
  19. 07:01Charge Weight Selection for Accurate No. 9
  20. 07:30Seating Die Setup for Subsonic Rounds
  21. 08:49Achieving Target OAL: 2.069"
  22. 09:09Range Test Setup: LabRadar
  23. 09:18Testing 8.8 Grain Subsonic Load
  24. 09:36Testing 8.6 Grain Subsonic Load
  25. 10:09Testing 8.0 Grain Subsonic Load
  26. 10:15Decision to Load More at 8.4 Grains
  27. 10:35Setting Up Powder Measure for 8.4 Grains
  28. 11:09Initial Charge Weight Reading (10.4 Grains)
  29. 11:37Dialing in 8.3 Grains for Subsonic
  30. 11:59Throwing Five Charges at 8.3 Grains
  31. 12:10Adjusting Gas Block
  32. 12:29Testing Five Subsonic Rounds
  33. 12:48Subsonic Velocity Results Analysis
  34. 13:04Decision to Load Remaining Bullets
  35. 13:22Loading 55 Subsonic Rounds
  36. 14:19Switching to Winchester 296 for Supers
  37. 14:27Supersonic Load: Less Drama
  38. 14:48Seating Die Setup for Flat Base Bullets
  39. 15:53Adjusting Seating Die for Flat Base Bullets
  40. 16:34Challenges with 300 Blackout Bullet Variety
  41. 16:45Achieving Target OAL: 2.050" for Supers
  42. 17:15Importance of Case Mouth Chamfer
  43. 17:46Slow and Steady Reloading Process
  44. 18:25Range Testing: Initial Zero at 20 Yards
  45. 18:38Moving Target to 50 Yards
  46. 18:44Testing Subsonic Rounds at 50 Yards
  47. 19:18Front Sight Adjustment for Subsonics
  48. 19:40Fine-Tuning Front Sight Post
  49. 19:57Subsonic Velocity Confirmation
  50. 20:13Testing Supersonic Rounds
  51. 20:20LabRadar in Rifle Mode
  52. 20:39Malfunction with Supersonic Rounds
  53. 20:47Adjusting Gas Block Down for Supers
  54. 21:13Further Gas Block Adjustment Down
  55. 21:23Supersonic Velocity Results
  56. 21:40Another Failure with Supers
  57. 21:45More Gas Block Adjustment Down
  58. 22:08Testing with Maximum Gas
  59. 22:28Gas Block Turned All the Way Down
  60. 22:39Switching to Steel Target
  61. 22:51Failure to Eject Spent Brass
  62. 22:56Gas Block Adjustment: 3 Clicks Out
  63. 23:07Bolt Lock-Back Achieved with Supers
  64. 23:10Switching Back to Subsonics
  65. 23:17Subsonic Failure to Eject
  66. 23:21Incremental Gas Adjustment for Subs
  67. 23:45Bolt Lock-Back Achieved with Subs
  68. 23:51Setting Minimum Gas for Subsonics
  69. 24:05Testing Three Subsonic Rounds
  70. 24:29Testing Five Supersonic Rounds
  71. 24:44Jamming Issue with Supers
  72. 24:50Buffer Consideration (H1)
  73. 25:03Accuracy Confirmation
  74. 25:07Conclusion: SBR is Functional
  75. 25:26Thanks and Sign-off

Frequently Asked Questions

What are the recommended powders for subsonic and supersonic 300 Blackout loads in an SBR?

For subsonic 300 Blackout loads, Accurate No. 9 is recommended for its faster burn rate in short barrels. For supersonic loads, Winchester 296 is a reliable choice that performs well across different barrel lengths.

What overall cartridge lengths are recommended for 190gr Sub-X and 110gr V-Max bullets in 300 Blackout?

For 190 grain Hornady Sub-X bullets in 300 Blackout, an overall length of 2.070 inches is recommended. For 110 grain V-Max bullets, the recommended overall length is 2.050 inches.

How do you adjust the gas system on a 300 Blackout SBR for subsonic ammunition?

Adjusting the gas block on a 300 Blackout SBR for subsonics involves incrementally increasing the gas until the bolt reliably locks back after each shot. This often requires more gas than anticipated for reliable cycling.

What are the challenges of reloading and shooting 300 Blackout in a Short Barreled Rifle (SBR)?

SBRs present challenges with gas system tuning, especially for subsonic loads, and are generally harder to shoot accurately than longer barreled rifles. Reloading requires precise OAL and careful powder selection for optimal performance and reliability.

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