Bren Gun: Help Needed!

[Peter Laidler]

OOOOOOOOOOps......... No need to worry Meerkos........ I was looking at the wrong part geometrically and mentioned the wrong fault so to speak. I say don't worry, but that doesn't mean about the dire state of the machining and where it is machined. The section that plays a most important part I mentioned is still intact. It is the small ramp that you can see in photo 4 with two little lumps at either side at the right hand end.

As the piston extension slides to the rear, the first 3/4" or so this ramp tightens up the extractor stay which transforms the extractor from being slightly articulated into becoming rock solid with the breech block and therefore grip the rim very tightly. This is COMMENCE TO UNLOCK and is part of another feature. During the next stage, the breech block will START TO UNLOCK and drop down at the rear, rotating about the front breech block stops. This causes the tight extractor - which is locked solid to the breech block - to tweak on the fired case and break it free from the tapered lock. That is the end of mechanical safety and the breech is free to open fully rearwards

Very simplified - but there you go. Your extractor stay ramp is still intact

What the sectioned thread part does illustrate is the complicated Mk1 piston (simplified in the Mk2 version) of having longitudinal ribs between the piston rings half way down the stem that cover the gas vents in the body - for reasons best known to someone in the universe somewhere which means you have to have an indexed thread and therefore more complications........ Total waste of time and only done because the licensing agreement said so! Deleted at the first opportunity for the simpler and just as effective Mk2 piston