Bren MK1m

[Flying10uk]

Plenty of people appear to quote "Bren MK1m" online but I haven't seen anyone actually confirm what the "m" actually stands for. Therefore, I'm curious to know what the "m" after the "1" in Bren MK1m means, please? I assume that it stands for "modified" but I haven't seen this confirmed anywhere. I realise that the MK1m came after the Mk1 and modifications to the Bren.

Many thanks

[Peter Laidler]

I think that the m designation was an indicator to Armourers and Quartermasters that the gun was of Canada origin and might come with certain parts or more likely, a combination of parts with which they are not familiar. It was made known in the equipment regulations that regardless of this, that where a PART might not be interchangeable, ALL the main sub assemblies are fully interchangeable. A couple of parts that I do recall were barrel nuts/latches and spring and bipods

[Lee Enfield]

Here is the explanation from the Canadian EME Precis on the Bren dated 11 Oct 1944.

[green]

Thought the m was for BREN MkI made w/o scope bracket.

[Flying10uk]

Thanks for the replies chaps.

[Peter Laidler]

The enlarged gas port in the barrel was developed long before the Mk1m gun. This didn't change the actual GUN designation. It did change the BARREL designation from Mk1 to Mk1*. But I could be wrong.....

The enlarged gas port was the beginning of a long sorry saga that plagued the Bren reputation for reliability. Designers did not take on board at the time, the bigger picture and that with all/most things mechanical, a change here......., for the better (?) inevitably had an effect further along the chain. In this case, several DIRE effects further along the line.

A classic example was changing the design of the flash eliminator from a straight venturi as designed at Brunn, to a 'choked' or stepped venturi............. and then back to how it was designed!

[MGMike]

A classic example was changing the design of the flash eliminator from a straight venturi as designed at Brunn, to a 'choked' or stepped venturi............. and then back to how it was designed!

Peter, what was the cause & effect here?

M

[Peter Laidler]

Very briefly, the gas would gather in the 'choked' part of the original stepped flash eliminator, to such an extent that it would very quickly close up. This affected the accuracy of the gun because the escaping gas travels faster than the bullet - and upset its flight. That's the reason why the flash eliminator scraper was incorpoorated into the original Bren multi/combination tool. By the time the crunchies got around to cleaning the flash eliminator, the residue was a diamond hard mass!!!!!

The later flash eliminators solved the problems. That is until the Mk4 short barrel came on stream (for the Mk3 gun...). It had a big flash and you'll notice that eliminator had a long choke point. But this didn't seem to be affected by carbon build-up.

[MGMike]

Thank you, Peter. You've given me a new chore. Now I need to spend some time closely examining the insides of flash hiders! I have a barrel with the early stepped flash hider, but I never gave much thought before to build-up or to scraping it.

M

[Surpmil]

Here is the explanation from the Canadian EME Precis on the Bren dated 11 Oct 1944.

Attachment 131185

So although not explicitly stated, the "M" presumably refers to "Modified", as per the modifications that text refers to?

Is the text correct in implying that the Czech-built guns also had the dovetail for the Sight. Fixed Line & No.32?