Q&A: All About Submachine Guns (May 2025)

Published on May 17, 2025
Duration: 67:55

This Q&A session with Ian McCollum of Forgotten Weapons delves into various aspects of submachine guns (SMGs). Key topics include the lack of cultural influence on firearm design, the historical development and contenders for the first SMG, typical military loadouts, the enduring relevance of the MP5, and the obsolescence debate against short-barreled carbines. The discussion also covers cartridge effectiveness, the challenges of rimmed cartridges in SMGs, magazine reliability, the distinction between SMGs and Pistol Caliber Carbines (PCCs), and the design choices behind open vs. closed bolt systems.

Quick Summary

Submachine guns (SMGs) are typically full-auto capable firearms chambered in pistol cartridges, designed for close-quarters combat. Pistol Caliber Carbines (PCCs) are semi-automatic versions, often with longer barrels, popular for civilian shooting sports and avoiding SBR regulations.

Chapters

  1. 00:00Introduction & Cultural Stereotypes in Gun Design
  2. 00:40The Sten Gun: Design Driven by Necessity
  3. 02:40American Submachine Gun Evolution: Thompson to M3
  4. 03:47French Submachine Gun Development: MAS 38 to MAT 49
  5. 04:24The First Submachine Gun: Villar Perosa vs. MP18
  6. 06:12Typical Military Submachine Gun Loadouts
  7. 08:09Why the MP5 Remains Relevant Today
  8. 11:10SMGs vs. Short-Barreled Carbines: Obsolescence Debate
  9. 14:44MP5 in 10mm: Bridging the Gap?
  10. 15:18Does Cartridge Caliber Matter in Submachine Guns?
  11. 20:18Why No .357 or .44 Magnum Submachine Guns?
  12. 22:35What Makes a Reliable Submachine Gun Magazine?
  13. 27:01Are Submachine Guns Still Issued in the US Military?
  14. 28:05Sten Gun Runaway Firing and Makeshift Grenade Use
  15. 30:19Why Britain Lacked Pre-WWII Submachine Guns
  16. 32:23PCCs vs. SMGs: Key Differences
  17. 34:45Straight vs. Curved Submachine Gun Magazines
  18. 36:18Locking Actions vs. Direct Blowback in SMGs
  19. 38:15Why Less Open-Bolt SMG Development Today
  20. 40:13UD42 Magazines: Permanently Coupled Design
  21. 42:48Where to Learn to Shoot a Submachine Gun
  22. 44:00National Level Submachine Gun Matches
  23. 45:03Why SMG Triggers Are Often Poor
  24. 46:19SMG Development if Battle Rifles Remained Standard
  25. 47:11Non-9mm/.45/.7.62x25 Submachine Guns
  26. 48:52Favorite .22LR and Submachine Guns
  27. 49:51Quality Construction vs. Stamped SMGs
  28. 51:14Is the PDW Concept Dead?
  29. 54:06The Remington-Thompson Cartridge
  30. 55:32Best Submachine Gun for Medieval Times
  31. 56:59Why America Used .45 ACP SMGs in WWII
  32. 59:01Why Few Submachine Guns Had Bayonets
  33. 61:01Viability of Magnetic Delayed Blowback
  34. 64:48Burst Fire vs. Full Auto on Machine Pistols
  35. 67:18Conclusion & Patreon Support

Frequently Asked Questions

What is the main difference between a submachine gun (SMG) and a Pistol Caliber Carbine (PCC)?

The primary distinction is select-fire capability. Submachine guns are designed for full-automatic fire, while Pistol Caliber Carbines are typically semi-automatic firearms chambered in pistol cartridges. PCCs also tend to have longer barrels (16 inches) for civilian legality.

Why is the MP5 still a relevant submachine gun despite its age?

The MP5 remains relevant due to its overall reliability, controllable handling, and established reputation. While it has some design drawbacks like a less-than-ideal trigger and reloading procedure, its proven track record and widespread adoption by military and police forces contribute to its continued use.

Does cartridge caliber significantly impact the effectiveness of submachine guns?

In military and police contexts, the caliber of a submachine gun cartridge generally has minimal impact on overall effectiveness. The primary goal is to hit the target, and for most common SMG calibers, achieving that goal is sufficient for mission success, rather than relying on extreme terminal ballistics.

Why are there fewer open-bolt submachine gun designs being developed today?

Modern SMG development favors closed-bolt designs due to better single-shot accuracy, a crisper trigger pull, and marketability in the US civilian market, which largely restricts open-bolt firearms. Open-bolt designs are simpler but can be harder to aim precisely for deliberate single shots.

What makes a submachine gun magazine reliable?

Reliable SMG magazines minimize friction. Features like rollers on the follower, ribs on the magazine body to reduce contact surface area, and robust construction with tight tolerances contribute to consistent feeding and fewer malfunctions.

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