Bren L4 / .308 build

So it begins with a Sarco torched L4 parts set.
These were cut hard and will take some TLC to get it working again.

The bolt , carrier and gas cylinder & bipod are the only non-molested parts.


https://i.imgur.com/c4m9oHU.jpg

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https://i.imgur.com/sBNr3jO.jpg

https://i.imgur.com/nFxpxKa.jpg

---------- Post added at 06:19 PM ---------- Previous post was at 06:18 PM ----------

I have one of the barrels Sarco sold with the parts set that needs fitted and chambered.

https://i.imgur.com/trLXSP5.jpg

---------- Post added at 06:20 PM ---------- Previous post was at 06:19 PM ----------

I have no lock nut area on the front.....
Going to use a piece from another build to replace.


The barrel socket and related holes are my 1st step.
Going to weld up solid and re-machine details.

I laser scanned a MKIII section for dimensions.
Much easier with real dimensions.

https://i.imgur.com/MBqoVYG.jpg

https://i.imgur.com/g0GzAuO.jpg

https://i.imgur.com/Ya9a2mk.jpg

https://i.imgur.com/U26As0Y.jpg

https://i.imgur.com/s7rYdts.jpg

---------- Post added at 06:22 PM ---------- Previous post was at 06:20 PM ----------

Relaxing day to do some welding...

https://i.imgur.com/wtUf2LN.jpg

https://i.imgur.com/oe8xQPl.jpg



About time to start cutting the weld I added to the missing sections. Copper slug in barrel socket did its job and had good fill out. My receiver has a socket insert where the barrel is inserted. They torched about 1/3 of it away so I welded it up on the face to hold it then build up the other missing areas. I have a cheap IR thermometer and weld until the temps hit 450'ish then give it a break then weld some more.

Left part of the original dust cover detent hole visible and the new one I drill should line up and clean it up.

https://i.imgur.com/vYK2WLt.jpg

https://i.imgur.com/nFxpxKa.jpg

https://i.imgur.com/Ze4If3M.jpg

https://i.imgur.com/S91ByUB.jpg

https://i.imgur.com/qu4W3SU.jpg

https://i.imgur.com/QmnLoJl.jpg

https://i.imgur.com/QssScMl.jpg

---------- Post added at 06:23 PM ---------- Previous post was at 06:22 PM ----------

Starting to machine welded areas. So far looking good with no voids , nice welds that are machining clean with carbide tooling.


One set up to match the angle on the mag well , inside area that was torched and the slots for the dust cover.
Next set up will be machining the barrel socket face and receiver sides.


https://i.imgur.com/ACAmYsJ.jpg

https://i.imgur.com/Q7hHuBG.jpg

https://i.imgur.com/4N7bEly.jpg



Worked on leaves for a few hours today , A flame thrower would be more fun getting them while on the tree.........


After welding the torched barrel socket I needed to massage it a little to get it to accept a Bren barrel. Socket internal diameter in .903"

The copper slug I put in the cut section did its job and I had a very slight amount of material to remove. Rather than buying a flex hone I made a simple lapping tool from round stock.

I used some valve lapping compound turned by hand with a socket to lap it out.

I will hand stone the face and other welded areas , blend them & blast it and more forward to doing the barrel nut section when I can get a block of free time. Work sucks at the end of the year for me but at least the yard work is ending.

Fixing the barrel socket is a fair amount of work and what keeps a lot of cut up Bren's from ever firing again.
The rest of my build should be pretty conventional.




https://i.imgur.com/o8AQVH3.jpg

https://i.imgur.com/AHS4CTv.jpg


Next up was drilling the detent holes for the dust cover and barrel nut. Dust cover hole is parallel with the front barrel socket face. Barrel nut detent in on an angle. Everything machined nice without any surprises.

https://i.imgur.com/Udcrpbw.jpg

https://i.imgur.com/QolmylT.jpg

https://i.imgur.com/nNHc8PJ.jpg



Moving on to the next section : Trashed barrel but area.

Torch guy wiped out the front barrel nut section as in its gone. I have a section from another parts set to use as a donor.
I will turn a copper slug the length of the barrel nut + an undecided amount to account for weld shrink.

Need to trim some pieces and fixture it up.


Blasted in the white~

https://i.imgur.com/gDNCSQP.jpg


Thank you torch guy~

https://i.imgur.com/pEloQ3U.jpg

---------- Post added at 06:24 PM ---------- Previous post was at 06:23 PM ----------

Barrel socket was about 3 sticks of filler rod and good practice for laying beads.

Next up -

https://i.imgur.com/zhcss9Z.jpg
https://i.imgur.com/nqSZXWo.jpg
https://i.imgur.com/oM4gpm0.jpg


Cleaned up the rest of my L4 , stripped all the parts and degreased everything including the wood. Discovered my bolt , slide , lower frame and what's left of my receiver all have the same serial numbers which was a big surprise. My other Brens are typically mixmasters. Internal parts are in really nice shape and not fired much from the appearance of parts, bolt face and gas piston. Wood has a good amount or wear around the sling attachment point. It was put away dirty and have some surface staining and has likely been that way for decades.


https://i.imgur.com/36JpjkE.jpg

https://i.imgur.com/zEz30Zf.jpg


Tacked the barrel nut section together in six places , removed the oversize ( +.012" length ) copper spacer and clamp assy. I fabricated and will weld it up. Hopefully my fixture helps keep the barrel nut surfaces parallel.

Guessing the shrink factor is always fun.


https://i.imgur.com/p33A8l7.jpg

Humble beginnings are the single blow of a hammer... Nice work so far on one of my favorites, a 7.62 Bren. They shot SO nice! Looking forward.

I admire this degree of skill and diligence.

The most incredible workmanship.

It warms the cockles of my heart to see such determined workmanship. A true Craftsman if ever I saw one.

Looks like a Daimler or Inglis A3 or an A5 Enfield 65 converted gun. Nice to see the front of the magazine housing. This was the absolute stumbling blocks during the conversion of the initial guns. Breaking through INTO the hole for the barrel nut plunger spring. NOT clear in the original drawings and only solved after cutting a body completely down the centre. Problem solved. To retain the plunger spring just drill DOWN at the rear of the rear end of the spring and insert a pin. Spring held, magazine lug housing recessed fully and problem solved.

If I recall correctly, the only NEW parts required during the conversion were the barrel of course, breech blocks - a direct copy from the old Inglis 7.92mm breech blocks, the flash eliminator and the backsight. Even this was the original with the surface ground off and re-engraved. Much like the magazine cover. Just the original, shortened and shaped at the ends to suit. Even the gas blocks were re-used - as were the foresight blocks. Simply unbrazed and pressed off.

If this were my project, I'd leave it as an MG20GA, A5, single barrel version. But if you were going with two barrels, I'd start with a .303 Mk2 barrel, long enough with lots of meat on it. Bore it out oversize and put in a 7.62mm liner.

A pleasure to ss work like this

The one I am working on and others like it was cut hard and never intended to fire again. I think they hit 99% of their target and not many are restored to firing condition.

Its a hobby for me and don't keep track of the hours but do what it takes to make it right.

I am now making tooling to cut the barrel nut face.
Welding shrink makes inserting the barrel nut impossible.
I could take it off the front of the nut but I want the barrel socket face and front barrel nut bearing area parallel.

Tooling will pilot off the barrel socket then ride on it cutting the front barrel nut area driven by a socket extension from the rear.

Its the final thing to do on this section then I can weld on the front gas cylinder section.

I would take the material from the FRONT of the barrel nut because the tightness of the barrel AND eventual CHS comes from the front face of the barrel nut bearing on its forward mating surface. The barrel nuts are VERY hard throughout. The buttress (?) thread of the barrel nut pulls the barrel back, tight, against the face pf the body.

We had facilities to bore out and re- bush worn barrel bearing faces where we couldn't get a barrel tight. Mind you, some Armourers with hand like shoulders of beef would tighten the barrels up like their lives depended on it. Not me........ Just a small hand pressure leverage on the nut and it'd click into place

Any eventual CHS problem will/can be adjusted with locking shoulders

OUTSTANDING WORK. One of the best rebuilds of one of the worst cut receiver types I have seen.
LOVE your welding work and use of backer jigs of your own making.

Later 42rocker

Looking at the pics I assume that the receiver was cut with a plasma cutter when it was made into a parts kit. Is that, generally how most parts kits are cut, with a plasma cutter, or are some cut with an oxyacetylene cutting torch? Whoever did the cutting of this receiver certainly appears to "have given it some" with the cutting, looking at the pictures posted here.

Quote:

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Originally Posted by Flying10uk

a plasma cutter, or are some cut with an oxyacetylene cutting torch

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I've seen some dewats for trophy type plaques that were done with plasma torch so it was just a line on the back to end it. This one looks like the gas axe meant to destroy it.

Quote:

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Originally Posted by Flying10uk

Looking at the pics I assume that the receiver was cut with a plasma cutter when it was made into a parts kit. Is that, generally how most parts kits are cut, with a plasma cutter, or are some cut with an oxyacetylene cutting torch? Whoever did the cutting of this receiver certainly appears to "have given it some" with the cutting, looking at the pictures posted here.

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Our BATFE requires all imported MG receivers cut with a oxy torch with a minimum of material removed in certain areas, at certain angles.
Some importers got creative with saw or plasma cutting then feathering the edge with a torch to make it appear like an oxy torch cut but that runs the risk of them being rejected.

Mine was for sure by the torch.

Its an L4A3.

I am happy to be off this week and cant remember the last Christmas week I had off from work in decades.

Welded the barrel nut section together and the weld shrink was about .012" more than I guesstimated. I was more concerned with keeping the barrel nut surfaces parallel for even contact with the nut. I decided to make a basic tool to cut the front barrel nut surface clean then fit the nut OAL for a nice fit.

The tool I made pilots off the barrel socket driven from a 1/4" socket extension from the rear. The cutting face is .010" larger than the barrel nut diameter. I used the adhesive backed "slip tape" people put on walkways , because I had a roll and everything was closed yesterday. It actually worked out pretty well.
After welding everything stayed pretty straight so I used a Sharpie and colored up the front barrel nut contact area and buzzed it with my Ryobi drill.

After it cleaned up I measured it then put the barrel nut in a 3-jaw chuck with and faced off the front of the nut a couple thousands , test fit then back and forth until it just started to slide in. I switched to valve lapping compound and worked it until the nut throws smoothly and goes in and out correctly.

Its a simple task but I try to get every section right before moving on, its time well spent and avoided compound problems.



Tool~

It slides in from the front , put large diameter in first , slide pilot thru into barrel socket then push in 3/16" dowel pin that drives it.
I stuck a piece of the non-slip tape on the face of it and trimmed it with a razor knife.

https://i.imgur.com/9DlCnxI.jpg

https://i.imgur.com/v4mFDv1.jpg

https://i.imgur.com/O9fjZKU.jpg

https://i.imgur.com/DrhZYBn.jpg

Nice and clean~

https://i.imgur.com/0pAznMh.jpg


Perfect fit~

https://i.imgur.com/xwmmLJx.jpg


Now that the barrel nut area is finished I can measure the front section , cut and get ready to weld.

https://i.imgur.com/lbGDL2r.jpg



Bren Gun repair tool to Machine Barrel Nut Face Parallel after Welding - YouTube

Nice work...

Again, I say VERY NICE WORK!!

Later 42rocker

Sarco....... and I spent a half day getting it fitted and its been interesting.

On mine the extractor relief clearance is clocked about 10 degrees off center when I got it to lock up.



I ended up lapping the hell out of the barrel threads ( the lead or extractor relieve is off ) to get it centered and locked up.

To do so I will require a .022" shim on the barrel face to lock up correctly with contact.



As a sanity check I have a bucked of several factory 303 barrels and all of them install and lock up correctly so its the Sarco barrel.



After getting it fitted I welded the front gas cylinder section on , without surprises.


Strangely , these all fit correctly~



https://i.imgur.com/glui95N.jpg


Extractor relief centered , need shim for the gap~



https://i.imgur.com/EhH6HDh.jpg





Locked up~



https://i.imgur.com/Cy87Wy4.jpg





Front section is reunited ~



https://i.imgur.com/oVAavys.jpg

Sweet! Were you in my bucket of barrels? LOL

Glad to hear everything is working, or locking for you.

Enjoy the Build

Later 42rocker

Pinned the gas block and pressed a dowel pin in place and milled the front of the barrel for the front sight assy.



Need to pin it and drill the gas hole in the barrel.



https://i.imgur.com/JGnzeOt.jpg



https://i.imgur.com/O75OrBw.jpg

Gas piston moving good? Seeing your work, I'll bet it does, just had to ask, lol.

You are doing a great job after starting out with a mgs type of demill.

Can't wait to see more.

Later 42rocker

Quote:

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Originally Posted by 42rocker

Gas piston moving good? Seeing your work, I'll bet it does, just had to ask, lol.

You are doing a great job after starting out with a mgs type of demill.

Can't wait to see more.

Later 42rocker

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Like a hot dog down a hallway.........Everything is lining up really well.

Bummed that I have to go back to work tomorrow.

Drilled the barrel gas port and drilled retaining pin hole for front sight assy. in barrel without issue or surprise.
Spent a good hour with hand files and grinder cleaning up the torch cut middle section. Most of the slag is gone but the torch melted metal into the grooves and other areas that makes it a PITA to clean up / out.

After clean up I see my cocking slot closed up in width after being torched. I will straighten it before setting headspace and welding sections together.
I have some big gaps to fill in. They are thin sections and fill in quickly with little filler rod.

The one surprise is a repair or revision section on the front cocking handle stop / retainer. This L4A3 came with a folding cocking handle Vs the unique MKII.
No idea if its a revision to use the standard cocking handle or a repair. Either way its been brazed / soldered in place and if you were unaware and tried welded on it solder or braze really makes a nice show when you light up on it with a welder.


Need to add bolt denial pins in both sides of the barrel socket section before welding the mag section to it to keep BATFE happy.


The factory revision / repair is very well done.

Braze visible on top~

https://i.imgur.com/0oHoeM5.jpg


Bottom dovetail visible~

https://i.imgur.com/KcjUTqH.jpg


End with braze line visible~

https://i.imgur.com/Zic9AQa.jpg


Too bad torch guy cant cut a straight line~

https://i.imgur.com/npM3IU3.jpg


Rear of slot closed up and separated with a parallel & shim.
This will be straightened out before welding sections together.

https://i.imgur.com/dKQxdBk.jpg

Now that's a gap to fill.

Looks like you are enjoying the build. Doing an outstanding job of it also.

Later 42rocker

Before joining the mag section together ( and set the headspace ) denial pins are required to keep an unmodified bolt from dropping in.

Bolt denial pin locations:

1.250" from the receiver barrel socket face
1.660" from the base of the receiver rail up.

I turned two denial pins from a grade 8 bolt .250" diameter x .230" OAL.
Tapped in flush with receiver wall/s then welded in place.

Tested with bolt in carrier for function then weld in place.


https://i.imgur.com/3bXz0dp.jpg



https://i.imgur.com/D3EMdA9.jpg

https://i.imgur.com/Dqw4TPP.jpg

https://i.imgur.com/gJrf5M2.jpg

https://i.imgur.com/hItVapz.jpg


Milled off the full auto sear catch from the carrier and piston post~


https://i.imgur.com/pGbbuGh.jpg


Rear section must have been torched by the same guy that cant cut a straight line on the other end of my L4.
Spacer in charging handle slot sets the correct space in the cocking slot. When mine was cut it spung in about .050". If its not set straight you will have issues with the striker , carrier assy and cocking handle fit. All have to travel freely and should slide back and forth by tilting.

https://i.imgur.com/ETCjUJh.jpg

https://i.imgur.com/oaNVECJ.jpg

https://i.imgur.com/ubZY6IE.jpg


I have a fixture that pins off the rear sight holes and take down hole to set the correct length.

https://i.imgur.com/sL3qmwF.jpg


Tacked and now ready to finish weld rear section together.
Might do some more welding tomorrow.

https://i.imgur.com/9acumDC.jpg


Mag adapter fits and so does an L1A1 mag~

https://i.imgur.com/8ajYz2v.jpg

Managed to get some build time on the L4.
Welding & porosity , a fun fight.

The rear section was cut thru the rear retaining pin hole ( that's not horrible to fix ) but ran into a few other issues that was a fight to get taken care of.
Torch guy wiped out the internal stepped area that has multiple intersecting cuts and filling them in typically is not a hassle. The rear edge of my receiver was cut thin like a sliver with the piece being pretty thin. When you weld things you get shrink. When you have a thin section welded to a larger section it pulls the smaller piece more than the larger piece.

in my case the thin rear section pulled in like a dish where the back edge of the receiver looked like a smiley face.
This area needs to be welded up and re-cut. No biggie.

The nagging issue I had was weld porosity welding up the sides. This usually comes from dirty metal , bad filler rod , gas issues , etc.
My barrel socket was torched hard and I ground the slag clean and welded it without issue. This back section was more melted by the torch than a cut and I think some crap was melted into the base metal. When you weld or have a puddle and run into dirt you get porosity and the dirt or slag makes a bigger crater or porosity in the weld. Sometimes you can add a dab of stainless steel filler rod and get it to flow out but this is going to be parked so it needs to be filled with similar carbon steel filler rod ( ER70 ).

I welded until I hit a spot that would not puddle with porosity then grind it out like a dentist does to fill a cavity then repeat. I did this WAY more times than I wanted to but its the only way to do it right. In hindsight if I was doing it again I would have ground away more metal in the melted area.

I have enough filler added to clean up and hit again if required.
Charging handle dropped in so my shim / spacer did its job.

Before making it pretty~

https://i.imgur.com/VgJUnYJ.jpg

https://i.imgur.com/f4eq3tw.jpg


Torch missed all the stepped area~

https://i.imgur.com/9MVppwq.jpg


Torch ate the other side~

https://i.imgur.com/CvTx1Md.jpg


Filling the gap pulled over the thin edge like a smiley face ~

https://i.imgur.com/oaNVECJ.jpg


Had to fill in the cut gap and edge and re-cut receiver face~

https://i.imgur.com/nYd4ovS.jpg

Nothing like having a complete machine shop to do the best work...very nice. Wish we could still do those here. Last one I did was an M2 .50 that had been a belly gun pack survivor.

You are doing an outstanding job!
Nice backer plates.

Wish you were in my area.

Later 42rocker

Working in circles between bathroom repair , work and Bren stuff.

Cleaned up welds and dimensionally everything is correct. Cocking handle fits and slides back and forth under its own weight. Rear take down pin hole welded up and re-machined so the pin fits like it should. Rear section slides on the frame and the bolt and carrier slide easily. I am ready to weld the front and aft section together. I will be using a dimension from the barrel socket face to the mag latch pin hole. This is a set dimension and I will be adding my guess for shrink amount to it. My barrel is "short" chambered with about .100" sticking out. You can see the same amount between the bolt face and the bolt stops in the receiver. You need to hit your headspace in this area because if you need more that the case stick out you will be hitting the bolt stops and cant go deeper. Using the Bren receiver dimension is safe because the magazine should fit and have room to ream the 7.62 chamber deeper to correct HS.


LOTS of unsupported case and way off the bolt stops~

https://i.imgur.com/mCjtVv4.jpg



Better~

https://i.imgur.com/CvTx1Md.jpg

https://i.imgur.com/J15W9py.jpg


https://i.imgur.com/f4eq3tw.jpg

https://i.imgur.com/ZjSHu5o.jpg


https://i.imgur.com/nYd4ovS.jpg

https://i.imgur.com/hnCu7wR.jpg

https://i.imgur.com/MBH4X6V.jpg


Now to find time to stick them together~

https://i.imgur.com/WG3Kx8Z.jpg

Lookin' mighty fine.

Coming along nicely. Work to be proud of.

Closing the gap.



Torch guy must hate bren guns but I think I am gaining on the damage done. I want to even the gap side to side for even finish welding. I will double check my spacing (I added .020" for shrink) then bridge the gap in alternate spacing LH bottom then RH, top of LH & RH then middle. After the receiver is tacked together in multiple places I can finish the welds.



The RH side by the mag well was bent / kicked out from the torch cutting or handling. I have it clamped with machinist clamps until it's attached to the receiver.



This section is welding WAY better than the rear section. No porosity or strange surprises.

I did grind the gap back more on both sides to guarantee clean metal. Grinding more material away is opposite what you want to do but you need clean metal or you will have more work to do.



https://i.imgur.com/FGtctor.jpg



https://i.imgur.com/NMe3bdD.jpg



https://i.imgur.com/lmNfFkU.jpg



https://i.imgur.com/uqRz718.jpg

Outstanding work and you are sharing so much great info as you are doing it. OUTSTANDING!

Later 42rocker

Some Bren guns were cut up with a passion of them never firing a shot ever again. It takes time to reverse the process. Not a lot of L4's around in firing condition full or semi. I did manage to get enough L4 mags to fill a mag case.

https://i.imgur.com/7gM5IEi.jpg

Nice, I had two for a while for my C1 rifle...they worked perfectly.

Quote:

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Originally Posted by cal50

to fill a mag case.

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Do you have a L4 mag case?

Quote:

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Originally Posted by Flying10uk

Do you have a L4 mag case?

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Just a beat up 303 mag case I will have to fix and modify.
I bid on one listed in the UK but got sniped at the end of the auction since I could not watch it.

Nothing more irritating than going to use your shop equipment and something does not work.

Went to use my tig welder ( I have a water cooled torch ) and noticed coolant on the floor....... return coolant hose blew and leaking.
Could not find a stand alone replacement hose so I removed the part from the welder and tapped it to a standard 1/8 NPT pipe thread and made a line.
Ended up flushing the old coolant , cleaning the pump filter and adding new coolant.

Blue hose is the original / leaker.

https://i.imgur.com/92bvxiy.jpg


Back in action.

https://i.imgur.com/HR0qZve.jpg



Its nice having the receiver back into one piece.
Checking the target print dimension after welding I am .010" short which should not be an issue. I added around .020" which got me close but had I added .030 " I would have been right on the money. If the magazine fits and my bolt stops do not hit the frame I should be able to set the headspace.

I underestimated how much filler metal was required in the larger sections by the frame rails and got a little more weld shrink.
Need to look at it with fresh eyes this week and fill anything I missed , then give it an over ride @400 F and remove it from the fixture.


https://i.imgur.com/DNXk2Fp.jpg

https://i.imgur.com/w5lTEc9.jpg

The addition of the cocking handle stop block on the Mk2 guns was a standard Base workshop and FTR work-over. There were two methods to retain it. The dovetail with braze or two horizontal pins through the block and into the body and braze.

The two pin method was the better option as I recall.

You are doing a fantastic job too.

The L4 gun mag boxes were initially simply converted Bren mag boxes with a wood batten 1"(?) thick and the width of the raised part that runs along the top of the box. It was screwed in from outside the box, through the recess and into the wood batten. Painted to suit and a strip of horsehair felt glued to it.

Later boxes were new-made. Similar. but approx 1" shallower to accommodate the L4 type magazines

Quote:

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Originally Posted by Peter Laidler

The addition of the cocking handle stop block on the Mk2 guns was a standard Base workshop and FTR work-over. There were two methods to retain it. The dovetail with braze of two horizontal pins through the block and into the body and braze.

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Whomever that did the cocking handle re-work did an excellent job.

I enjoy seeing craftmanship and things done correctly.

What you think of the Mk2 cocking handle stop modification is JUST what I thin k of your workmanship Cal50! It's a true pleasure to see your kind of workmanship. And on a trusty L4 gun, it makes my day.

There has always been a bit of friendly dispute about the A3 gun and the A5 gun. Indeed, even the EMER's, the parts lista and the Navy BR's (their Book of Reference) seem to differ. This is what I say.

The A3 gun followed the A2 gun - with two early barrels that were soon shot-out. The A4 gun did away with both the early barrels in place of ONE chrome lined barrel that was very successful. It necessarily follows that the A3 gun should follow that natural progression.

Otherwise you''d have the absurd siruation of the A3 gun being an improvement on the A2 gun............ but the A5 gun being a downgrade of the A4 gun. And since Enfielkd had ceased the manufacture of the early two barrel barrels, where were they going to get these barrels for the newly introduced A5 gun?

I don't understand it either. A2 and 3 guns, 2 barrels. Upgraded A4 and 5 guns, 1 barrel

Just picked this up locally for a good price, your build is a solid inspiration. Now to either find a builder or make a new great friend :)

https://i.imgur.com/sEtR9W7.jpeg

Quote:

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Originally Posted by newcastleadam

Just picked this up locally for a good price

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At least you know there's a source of info for your build.

Quote:

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Originally Posted by browningautorifle

At least you know there's a source of info for your build.

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Very true!

Exterior weld cleanup.

Using aluminum oxide abrasive 2" disc's and my air die grinder on exterior welds. It can knock it down quickly but if you are not careful it can cause you extra work. I will get it cosmetically OK but will not really finish it until I have successful test fire and function.



Now I move to the inside of the receiver to recut all the slots that are welded shut.

I plan to parkerize & paint the receiver.



https://i.imgur.com/mb9CDh2.jpg



https://i.imgur.com/6HG2pGH.jpg

Internal weld cleanup.

Machining out the lower frame and bolt carrier guide rails.
Keycutter did it's task and lower frame slides on and the bolt carrier has full travel without any tight spots.

https://i.imgur.com/sa5cftP.jpg

https://i.imgur.com/p2mi4DV.jpg


Cleaning up the dust cover slot and area to accept the L4 magazine catch. Lots of little things to clean up after a successful test fire and function.

https://i.imgur.com/arfJIbE.jpg

https://i.imgur.com/2IM35LD.jpg

I hope that he won't mine me saying but Brian at BDL has the UK spec parkerising process off to a fine art and as I understand it, also has the UK spec sunkorite spirit based heat resisting paint. An L4 gun deserves it.....

A friend of mine reminded me a couple of weeks ago that in UK Naval service, what killed the L4A3 and 5 guns eventually was the press-in gas cylinder. Mind you, those navy recruit types were probably flogging the same old guns to death day after day, week in and week out!

I say again

OUTSTANDING WORK!!!

The large number of Brens I've seen have huge gaps in some of the inside welded areas. You do good work, Very Nice!!

Later 42rocker

Just out of interest, what sort of speed did you run that keyway cutter at, post 43? It is good that you can machine the welds in the keyways with a "high speed steel" cutter rather than a carbide cutter.

Quote:

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Originally Posted by 42rocker

I say again

OUTSTANDING WORK!!!

The large number of Brens I've seen have huge gaps in some of the inside welded areas. You do good work, Very Nice!!

Later 42rocker

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Of all the welds repairing the Bren the cut in the mag well is the most important IMHO. It's this section that holds the locking shoulder to set headspace and holds the pressure on firing. You want full thickness welds.

Most of the other weld are far less critical.

---------- Post added at 11:04 AM ---------- Previous post was at 11:01 AM ----------

Quote:

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Originally Posted by Flying10uk

Just out of interest, what sort of speed did you run that keyway cutter at, post 43? It is good that you can machine the welds in the keyways with a "high speed steel" cutter rather than a carbide cutter.

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800 RPM with good cutting oil.

ER70 filler rod is similar to the base metal and will machine nice if you do not overheat the weld.

Cutting back mag well weld material and L4 magazine adapter now fits again. Tested a few L1A1 20's and all 12 of my L4 mags and they all fit VERY nice.
I think I am close to being too tight / too much weld shrink but mags literally fit perfect. Easy in , out and no wobble.

Inserting bolt its short of fully locking. I am tighter than the nominal print dimension and it moved the locking shoulder closer to the frame bolt stops.
I am going to do a cast of the locking shoulder space with it removed and measure it to the L4 locking shoulder overall length.

I need it to lock and have some space between the frame stops and bolt. After I get this dimension set I can headspace the barrel.


When it fits it makes me smile~

https://i.imgur.com/UCC1KfN.jpg



When the magazine fits and locks in I really smile~

https://i.imgur.com/oPgO4nS.jpg