Q&A November 2025: The 6.8x51 is Still a Bad Idea

Published on November 22, 2025
Duration: 72:33

This Q&A session from Forgotten Weapons covers a wide range of firearms-related topics. Ian McCollum discusses the evolution of red dot sights, the importance of blood lead level testing for shooters, and the nuances of various historical and modern firearms, including the 5.56 NATO cartridge's twist rate evolution, the M14's manufacturing issues, and the challenges of polymer-cased ammunition. He also touches on niche subjects like underwater firearms, electromagnetic rifles, and the future of handgun design.

Quick Summary

The 30-round magazine capacity is a sweet spot balancing ammunition capacity with engineering challenges. Longer magazines increase spring force differentials, feed lip stress, and awkwardness in storage and prone shooting, making them less practical and more expensive to engineer reliably.

Chapters

  1. 00:00Introduction & Aimpoint Duty RDSMR
  2. 01:55Blood Lead Levels and Shooting Safety
  3. 04:13Kuro Distillery & Finnish Rye Whiskey
  4. 06:00Scuba Diving & Firearms Travel Plans
  5. 07:515.56 NATO Twist Rate & M855 Ammunition
  6. 10:30Sight Preference vs. Performance
  7. 11:45Calico Drum Magazine Reliability Issues
  8. 13:25Pistols of the Warlords & Ben Shu Feedback
  9. 15:06Finnish RK62 & Small Arms Development
  10. 18:19Favorite Tanks & Playgrounds
  11. 20:38Rock Island Arsenal 1903 & Cosmoline
  12. 22:32Firearms Reference Library Size
  13. 23:42M3 Snooper Carbine & Night Vision
  14. 26:54Polymer Cased Ammunition Challenges
  15. 30:05Post-War SMG Development & Intermediate Cartridges
  16. 31:27Electromagnetic Rifles & Railguns
  17. 34:05European Military Surplus Parts Kits
  18. 35:50Primer Actuated Designs & Future Mechanisms
  19. 37:52Good Enough vs. Really Good Rifles for Militaries
  20. 41:21M14 Hate & Reputation Analysis
  21. 45:0530-Round Magazine Standard & Reliability
  22. 49:27Remington Model 51/53 Hesitation Lock
  23. 51:496.8x51mm in GPMGs & DMRs
  24. 54:419mm Luger's Rise to Dominance
  25. 57:30Shotgun Use for Anti-Drone
  26. 58:25Suppressed Revolvers & Case-Sealed Actions
  27. 60:18Moons Out 2026: Night Shooting Skills
  28. 62:22Exotic Pistols vs. Mass Market Acceptance
  29. 66:22European Book Availability
  30. 67:46Maxim vs. Browning Machine Gun Influence

Frequently Asked Questions

What are the main challenges with polymer-cased ammunition?

Polymer-cased ammunition faces challenges with sealing the chamber, extraction reliability, and bonding to metallic case heads. While lighter, these issues often outweigh the weight savings for infantry rifle cartridges, making brass the preferred material for its proven performance.

Why is the 30-round magazine capacity a common standard?

The 30-round capacity represents a sweet spot where magazine reliability is achievable with standard coil springs. Longer magazines increase spring force differentials, feed lip stress, and awkwardness in storage and prone shooting, making them less practical and more expensive to engineer reliably.

What was the reason for the change in 5.56 NATO barrel twist rates?

The shift from slower (1:12) to faster (1:7) twist rates for 5.56 NATO barrels was primarily to stabilize the heavier, longer M855 (SS109) cartridge, which features a semi-armor-piercing projectile and a steel penetrator.

Is the 6.8x51mm cartridge a good idea for general-purpose machine guns?

While the 6.8x51mm cartridge offers benefits for short-barreled rifles, its high pressure is not necessary for machine guns with longer barrels. Traditional cartridge designs can achieve similar velocities without the complexity, accelerated barrel wear, and manufacturing challenges associated with the 6.8x51mm's hybrid case.

Why did the M14 rifle develop a negative reputation?

The M14's reputation suffered primarily from widespread manufacturing issues and inconsistent quality control, leading to reliability problems. Soldiers who received properly accepted firearms generally liked them, but the program itself was a logistical and production disaster.

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