Rifling on the *outside* of the barrel? The SR-11 with firearms and weapons expert Jonathan Ferguson

Published on June 14, 2023
Duration: 20:56

The SR-11, designed by Russell Shepherd Robinson in 1944, was an innovative Australian machine pistol or PDW concept focused on 'constant recoil' to reduce muzzle rise. It featured a unique auto-ejecting magazine for rapid reloads and a telescoping buttstock usable as a cleaning rod. Despite its advanced design, including external barrel rifling to counteract torque, accuracy issues due to heavy slide action and the end of WWII led to its rejection in favor of the Sterling submachine gun.

Quick Summary

The SR-11 machine pistol featured a unique 'constant recoil' design and external barrel rifling. Its helical fluting engaged the slide to rotate the barrel, counteracting bullet torque. It also had an auto-ejecting magazine for rapid reloads, though this was non-functional on the prototype.

Chapters

  1. 00:00Introduction to the SR-11
  2. 01:43Designer and Constant Recoil Concept
  3. 03:53Unique Buttstock and Cleaning Rod
  4. 05:45Auto-Ejecting Magazine Feature
  5. 09:35External Barrel Rifling Explained
  6. 13:21Performance and Accuracy Issues
  7. 18:03Historical Context and Rejection

Frequently Asked Questions

What was the primary design goal of the SR-11 machine pistol?

The SR-11 was designed around the concept of 'constant recoil.' The goal was to keep its working parts in motion to prevent them from slamming into the back of the receiver, thereby reducing muzzle rise during automatic fire.

What made the SR-11's barrel design unusual?

The SR-11 featured helical fluting on the outside of the barrel. These external grooves were designed to engage with the slide during firing, rotating the barrel to counteract the torque generated by the bullet's spin.

Did the SR-11's auto-ejecting magazine work effectively?

The SR-11 was designed to automatically eject its magazine after the last shot, enabling extremely rapid reloads. However, this feature was non-functional on the museum's worn prototype, limiting its practical demonstration.

Why was the SR-11 ultimately rejected for adoption?

Despite its innovations, the SR-11 faced accuracy issues due to muzzle dip from its heavy slide action. Furthermore, by the time the design was optimized in 1948, the war had ended, and Britain opted for the Patchett (Sterling) submachine gun.

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