Fixed up Bren Mk I

[Peter Laidler]

Mention of DP Brens reminds me that the biggest killer of Mk1 Brens was the inability to get CHS due to worn breech block stops and barrel bearings. And for Mk2's, that and loose gas cylinders caused by worn press-in gas cylinder area. I seem to recall that there were plans afoot during Base workshop repairs, to fit threaded Mk1 and 3 type gas cylinders while converting them to Mk2/1 folding cocking handle spec. I used to see plenty of DP Mk1's but only a few Mk2's. There were some Mk3 DP's but these and the Mk1's and 2's were all later under the new catch-all umbrella of DP Machine gun L54 A1

The real irony of the L54 guns was that as they were not classed as firearms and virtually irreversible, plenty were sold on as inert by plenty of dealers in the early to mid 70's. A large dealer in Plymouth was a big buyer and dealer who disposed of them to whoever wanted one for his Ferret reccy vehicle

I think I have said elsewhere that in the main, the Mk2 Brens were the mainstay of the UK and Canadian forces in Europe while the Mk3's were the backbone of the Infantry in the Far East.

Worn breech block stops was also a problem for the L4 guns too but because of the geometry it was possible to stone the beating surface back to achieve CHS

[MGMike]

Peter, I am sorry but I am not following the terminology. What surfaces are you referencing when you write "breech block stops" and "barrel bearings"? And was the inability to achieve CHS within tolerance a matter of too little or too much?

M

[Peter Laidler]

Hi MG Mike,

In our terminology, as used in the Armourers workshops, the breech block stope were the beating surfaces on the left and right hand side of the bolt way that stopped the forward movement of the breech block on a what we call a 'dry gun' That is with no ammo. The breech block hits these stops and gradually wears/beats them down. On a live firing gun, the cartridge in the chamber indicates that that's as far as the breech block will go.

The barrel bearing is the ring in the body that the barrel seats firmly against when the barrel nut is tightened down. There was a repair at Base Workshops to bore this area out and fit a new barrel bearing. Worn barrel bearing was one that wouldn't allow a barrel to be fitted tightly even with the No6 (?) barrel nut. The .303 BRen had barrel nut spacers to correct it but, alas, not the L4 guns.

Quite why, nobody really knew!!!!!!! The barrel nut spacers certainly would fix the problem.

As a general rule, taught to us, the spacers could only be used on one of the barrels of the pair. If both barrels needed spacers when the No6 barrel nut was fitted, the gun was ZF. Fitting barrels and breech blocks and CHS was a bit of a nightmare to be honest, especially for those Armourers brought up on the Bren that suddenly found that the same criteria couldn't be used on the newer L4 guns......... that were really just old re-worked Brens!

The same sort of criteria applied to our later L3 Brownings........ which were really our old M1919's internally re-designed by Biffo-the-bear one evening after a drunken party in the woods.................

[browningautorifle]

our old M1919's internally re-designed by Biffo-the-bear one evening after a drunken party in the woods.................

That is correct...

[MGMike]

Peter: Thank you for the detailed explanation. But it raises a further question: Why would beaten-down breech block stops in the receiover render the gun functionally unserviceable? When a barrel is installed and a cartridge chambered, the extra space for forward bolt travel would seem immaterial. The bolt is going to halt against the cartridge rim leaving zero headspace or, failing that, against the rear face of the barrel, in which case the stops play no role in the resulting headspace. What am I missing?

M