Bren L4 Build Oddity? (New to Bren builds)

Hello all,
I'm new here and I'm starting on a Bren L4 build and have some questions that I couldn't find answers to while reading and searching through the forum. So here goes nothing....

The kit: a Bren L4a4 that started its life as a MkIII with a 1945 date stamped on the side. It now sits in 4 torch cut pieces on my work bench. I actually ordered a MkIII parts kit and received this L4 by mistake from the company I ordered from. It actually turned out to be not such a bad thing as I mostly shoot 7.62 nato in my rifles, so one less caliber to shop for I guess.

The worst cut is in the barrel sleeve section of the receiver. It's not THAT bad and I've seen kits with much worse cuts in much worse places. It's mostly cosmetic and will be built back with weld (which I've already started. I'll get to that in a bit). There's about 80% of the original barrel shoulder/face left so I have an actual location to go off of.

My first question is more of a curiosity because I've never seen this type of thing come up in any Bren build that I've read or watched online. As I was welding the front of the mag well/barrel face/shoulder section, I noticed that there was some sort of separation in the barrel sleeve of the receiver. It looks as though there is some sort of "ring" sleeve on the front ≈1/4" of the barrel sleeve of the receiver. I never noticed this while preparing the kit for reweld. But when I was building up weld in this area, I noticed separation and movement of the "ring". Looking at Bren parts diagrams, exploded views, and blueprints, I can't find a name for this part or even proof of its existence anywhere. Being fairly familiar with most weapon systems, the only conclusion I could come up with is that, because this is a L4 and is modified from a previously mkIII Bren, it had a partial sleeve inserted into the bore to possibly fit a different barrel profile or tolerance for the 7.62 nato barrels? Can anybody confirm this? I haven't read anything about this anywhere.

I will attempt to post pictures of what I am talking about.

Here are some pics of the area. Please excuse the not-so-great welding and quick machining. Its a work in progress and it is far from done. I work on it when I get time.

https://www.milsurps.com/showthread....highlight=shim
I thought this would help you, but it doesn't:
The shims go onto the barrel, the collet looking thing is a tool to keep the shim square as it was installed onto the barrel.

My L4 as cut , you can see an edge of the "socket"

https://www.milsurps.com/images/impo.../vYK2WLt-1.jpg

https://www.milsurps.com/images/impo.../ubQ09gH-1.jpg

---------- Post added at 05:01 PM ---------- Previous post was at 04:56 PM ----------

Some dimensions that might come in handy.
I laser scanned a MKIIK for the hole locations.

https://www.milsurps.com/images/impo.../U26As0Y-1.jpg

https://www.milsurps.com/images/impo.../s7rYdts-1.jpg


https://www.milsurps.com/images/impo.../g0GzAuO-1.jpg

https://www.milsurps.com/images/impo.../Ya9a2mk-1.jpg

Wow, thank you for those! Those will absolutely come in handy!

The torch cuts on your receiver are pretty nasty. They got that torch nice and HOT when they sliced through that. The cutter must have been having a bad day at work.

When you say "socket" is that an official term? Or is this a term you came up with?

Do you have any idea why that would be inserted in there? Headspacing maybe? Or maybe it was heat treated harder due to the nature if it's location?

Also, I couldn't find a part name for this or that it even existed on any bren blueprints or parts diagrams. Is this strictly a L4 modification?

I'm wondering if I will have to have that area re-bored and have to turn out a new piece if I can't find one for sale online. That'd be a major operation to have that area re-bored due to the length of the receiver, the fixtures required, and the instability of what a lathe chuck would have to grab on to. I don't have to tooling to do that on a mill. I don't think I'd want to do it on a mill either.

cal50, thanks for the great reply! It's much appreciated.

That all looks SO hard to sort out. So much slag to grind and edges to rebuild...I had a .50HMG once to rebuild but it was nowhere near that destroyed. I understand the desire to bring it back though...

My shooting bud already put his L4 back together and his had the socket / insert. I also am not sure what the proper name is but its an insert / socket ,lol.
I have never seen an L4 that was not cut REALLY hard. I plan on machining a copper insert for the barrel socket area and welding everything else up solid then re-machining it to the correct specs.

I ground off all the slag and slid the pieces together and its in my pile of stuff to do.

https://www.milsurps.com/images/impo.../TVil8XZ-1.jpg

https://www.milsurps.com/images/impo.../YIaMyfB-1.jpg

https://www.milsurps.com/images/impo.../sBNr3jO-1.jpg

---------- Post added at 06:48 AM ---------- Previous post was at 06:46 AM ----------

Quote:

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Originally Posted by browningautorifle

That all looks SO hard to sort out. So much slag to grind and edges to rebuild...I had a .50HMG once to rebuild but it was nowhere near that destroyed. I understand the desire to bring it back though...

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Someone really enjoyed torching mine by the looks of it.
Its not a quick or easy fix but rescuing any old war horse is a good thing.

Quote:

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Originally Posted by cal50

I also am not sure what the proper name is

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Normally an item such as this is called a "bush", like a bearing or something to reduce a diameter or provide a harder surface. I can't think that it would be called anything else but there is probably another word to go with it describing what sort of "bush" it is, i.e. it's location in the receiver.

Here are some pics of my kit before I started filing and grinding and making it look nice prior to lining up and welding. The cuts on mine aren't bad at all compared to some I've seen.

And yes, I realize that those are MKII barrels and .303 mags in a L4. It's what I had on hand. When I ordered the kit, I thought I was getting a MK3 so I ordered 2 barrels and a mag to go with the kit that I thought I was getting.

That area in front of the mag will need an awful lot of work. There’s a lot of close tolerance parts to fit in there.