Very Rare and Mostly Pointless: the Bren Fixed Line Sight

Published on February 25, 2021
Duration: 7:09

This entry details the Plessey Fixed Line Sight Mark I, a rare accessory for early Bren guns, as explained by firearms expert Ian McCollum. It covers the sight's functionality for returning to a specific point of aim when using a tripod, its comparison to the Vickers Dial Sight, and its historical context, including why it was largely deemed unnecessary and subsequently removed from production after the retreat from Dunkirk. The rarity of surviving examples is also highlighted.

Quick Summary

The Plessey Fixed Line Sight Mark I was a rare accessory for early Bren guns, designed to help gunners return to a specific point of aim when using a tripod. It featured an occluded eye optic with a triangular pointer and mounted via a dovetail bracket. Despite potentially thousands made, few survive due to production simplification after Dunkirk and its limited combat necessity compared to tools like the Vickers Dial Sight.

Chapters

  1. 00:00Introduction to the Bren Fixed Line Sight
  2. 00:46Mounting and Storage
  3. 01:31Comparison with Vickers Dial Sight
  4. 03:13Functionality and Tactical Use
  5. 05:43Historical Context and Rarity

Frequently Asked Questions

What was the purpose of the Plessey Fixed Line Sight Mark I for the Bren Gun?

The Plessey Fixed Line Sight Mark I was designed to help a Bren gunner re-establish a precise point of aim when using a tripod. It allowed the gunner to remove the weapon for mobile use and then remount it to the exact previous defensive position by aligning the sight with a fixed reference point.

Why is the Plessey Fixed Line Sight Mark I considered rare?

The sight proved largely unnecessary for the Bren's actual combat role. Following the retreat from Dunkirk, British production simplified, and the mounting bracket for this sight was removed entirely. Consequently, very few examples survive today, despite potentially thousands being manufactured.

How did the Plessey Fixed Line Sight Mark I compare to the Vickers Dial Sight?

Both were adopted around 1939. While they shared optical assemblies and mounting brackets, they served different purposes. The Vickers Dial Sight was a complex tool for coordinating indirect fire, whereas the Plessey Fixed Line Sight was a simpler aid for returning to a specific point of aim for direct fire.

What are the key features of the Plessey Fixed Line Sight Mark I?

It featured an occluded eye style optic with a triangular pointer, mounted via a dovetail bracket with a thumb screw. It was designed for the .303 British Bren Gun and came with a canvas carry pouch.

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