AR-15 / M16 Rifle History, Part IV ~ Over half century of service!

Published on December 12, 2017
Duration: 43:17

This guide details the proper installation and configuration of a marksman shooting sling for an AR-15 rifle. It covers dismantling the sling, correctly threading components, and attaching it to the rifle. The video also explains how to adjust the sling for various shooting positions, including prone, sitting, and kneeling, and how to transition between a shooting sling and a carry sling. The instructor emphasizes the importance of correct sling setup for stability and performance in the field.

Quick Summary

The M16A1 featured key improvements like a chrome-lined bore and a modified buffer tube to accommodate faster-burning ball powder, enhancing reliability. Its twist rate changed from 14-inch to 12-inch to improve bullet stability in dense air and vegetation by increasing RPM. Extremely fast twist barrels can deform lightweight bullets, impacting accuracy.

Chapters

  1. 00:05Introduction to M16/AR-15 History
  2. 00:41M16A1 Improvements: Chrome Bore & Buffer
  3. 01:30Addressing Early M16 Reliability Issues
  4. 04:01Rifling Twist Rate: 14-inch vs 12-inch
  5. 05:22Military Bullet Ballistics & Tissue Damage
  6. 09:35Bullet Stability in Dense Air
  7. 11:46Fast Twist Barrels & Bullet Deformation
  8. 13:091971 Sierra Testing: 1-in-12 Twist Barrels
  9. 15:46Fast Twist Barrel Limitations
  10. 18:00Bullet Jacket Integrity & Fast Twists
  11. 20:20M16A1 Performance & Longevity
  12. 20:54Velocity vs. Barrel Length
  13. 22:50M4/A4 Variations: Flattop & Forward Assist
  14. 23:49M4A4 Stock & Buffer Tube Improvements
  15. 25:21Flattop Configuration & Optic Mounting
  16. 27:01Installing a Marksman Shooting Sling
  17. 33:33Sling Installed & Carry Sling Mode
  18. 34:41Adjusting the Sling for Shooting Positions
  19. 36:31Sling Use in Different Shooting Positions
  20. 39:14Transitioning Back to Carry Sling
  21. 39:26Conclusion & Final Thoughts

Frequently Asked Questions

What were the main improvements in the M16A1 compared to earlier versions?

The M16A1 introduced a chrome-lined bore for increased durability and a modified buffer tube to better handle the faster-burning ball powder used at the time. These changes improved the rifle's cycling rate and reduced residue buildup, enhancing reliability.

Why did the M16's twist rate change from 14-inch to 12-inch?

The change to a 12-inch twist rate in the M16A1 was implemented to improve bullet stability, particularly in challenging conditions like dense air or when passing through vegetation. This faster twist rate increases the bullet's rotational speed (RPM), helping it maintain a stable flight path.

Can fast twist barrels on AR-15s cause bullet issues?

Yes, extremely fast twist barrels, such as 1-in-7 inch, can cause problems with lightweight bullets that have thin jackets. The high rotational stress can deform or even cause the bullet to burst in flight, leading to significant accuracy degradation.

How do you properly install and adjust a shooting sling on an AR-15?

Installation involves correctly threading the sling's components through the rifle's loops and buckle. For shooting, the loop should be positioned high on the bicep for stability, providing support for various shooting positions like prone or kneeling. Proper adjustment is key for consistent support.

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