7.62mm L4 series........

[Peter Laidler]

The bipod sleeve (the part the rotates on the gas cylinder) is wrong too. You could re-profile the mid section of the barrel to suit if you were so inclined. An L4 type flash eliminator should be easy to obtain and fit. Then you'll have an externally almost perfect L4

[scoobsean]

Is the bipod sleeve not the standard mark1 fitting? This is how I bought the bipod. I have a mark2 bipod too. Should it be a hibrid of the two?

[Peter Laidler]

Hopefully KevG will put up a photo! But basically, the L4 bipod sleeve has a steel shroud that extends rearwards over the gas cylinder vents. Simply to shield the brighter flash that comes from the 7.62mm blast venting from the gas cyl.

Off the subject - sort of for a minute....... This was a bit troublesome on the Navy L4A3 and 5 guns because the ferocious blast was directed rearwards onto the blast plate which was a separate part on the ex Mk2/A3 and 5 guns. The blast plate was meant to be fixed solidly to the gun body (through the medium a tapered cross-pin) but the blast could cause it to work loose. The inspection standard was relaxed by the NOD so that slight looseness was acceptable providing that......... And off it went on and on and on.

Now where is KevG with the photo.......?

[scoobsean]

Hopefully KevG will put up a photo! But basically, the L4 bipod sleeve has a steel shroud that extends rearwards over the gas cylinder vents. Simply to shield the brighter flash that comes from the 7.62mm blast venting from the gas cyl.

Off the subject - sort of for a minute....... This was a bit troublesome on the Navy L4A3 and 5 guns because the ferocious blast was directed rearwards onto the blast plate which was a separate part on the ex Mk2/A3 and 5 guns. The blast plate was meant to be fixed solidly to the gun body (through the medium a tapered cross-pin) but the blast could cause it to work loose. The inspection standard was relaxed by the NOD so that slight looseness was acceptable providing that......... And off it went on and on and on.

Now where is KevG with the photo.......?

I googled some photos and see what you refer to. Is the cone welded on or does it just slide on before you fit the bipod? Seems like an easy piece to loose if not fixed to the gas tube or bipod.

[Peter Laidler]

Sleeve machined round and tubular shroud brazed all round. The L4 type bipod sleeve was approved for fitting on all Bren guns after May 74 subject to a WSE notice being issued....... Don't worry about the technicalities!

[TactAdv]

.......stolen pictures, for discussion.

-TomH

[Peter Laidler]

That's the one. Thanks Tom. You can see that the factory conversion to L4 didn't waste anything! The actual sleeve was turned down to accept the shroud part. Even the old .303" barrels were stripped of the gas blocks and re-used on 7.62mm barrels. You can occasionally see the former makers mark or logo. The foresight blocks were also utilised on the new fluted flash eliminators. Backsight leaves were also ground down .014" and new 7.62mm markings were engraved (or were they rolled?)

Depending on the size of the buying nation chequebook, the Mk2 butt slides were slimmed down and contoured to Mk3 spec too.

There was a drawback to the shrouded L4 type bipod sleeve. It simply wasn't as robust or tough as the old sleeve (Pic 3, top left). The sling loop part was machined off during the conversion but it was THIS loop that prevented the gun tipping over onto its left side. On the L4, all that prevented the gun tipping was the flimsy shroud that interfered with the barrel. A few bashes against the barrel and the shroud would collapse......., followed by the gun!

Pic 1 shows what I mean about the bipod sleeve shroud. It directed the ferocious blast of spent gas onto the blast plate - that's the plate, just behind the shroud. The plate is sandwiched between the gas cylinder that's retained by the visible taper pin and the body. Originally the blast shield should be TIGHT but the relaxed NOD directive later stated that a slight amount of movement (which is never defined of course!) was permissible but the actual GAS cylinder must remain tight.

I was told by one of the RSAF 'Lockies' that the conversion also entailed the use of threaded Mk3 type gas cylinders. This is incorrect and not possible.

Interesting thread

[Joe H]

Guys,

I'm trying to get straight what goes with what. I have never handled a 7.92 or L4 Bren.

I know:

.303 British Barrel with .303 British breech block

SA .308 barrel with .303 British breech block (L-4 Extractor)

.303 British Barrel (re-bored & re-chambered to 7.92(8mm Mauser))with .303 British breech block (L-4 Extractor)

What I'm not sure of???

7.92 (8mm Mauser) Barrel with 7.92 Breech Block (not the same as the .303??)

7.62 Nato L4 Barrel with 7.62 Nato Breech Block (Same breech block as 7.92????)

I believe I read somewhere that the 7.92 breech bolts were used in the L-4 conversions. Also the 7.92 breech blocks / 7.92 barrels were made different from the .303 so that a .303 couldn't be inadvertently chambered in the 7.92.
Thanks for your comments,

Joe

[TactAdv]

Joe, Yes, you are correct in your combinations above.

The reason for having to match (original Inglis) 8mm barrel + bolt, and L4 barrel + bolt is that those particular bolts are physically dimensioned differently than a std .303 bolt, for just the reason you stated.

This is the epiphany that the guys at DENEL had.....if you simply made the barrel shank of a new-made .308 barrel LONGER (by the length of the cartridge feed horns on the bolt), you could then keep the std .303 bolt and not have to make new ones specific to the caliber change. Apparently, they regarded the off chance of someone trying to use the wrong ammo a worthwhile gamble in light of NOT having to make another new (and expensive) part at the time (of international embargo). With just the "longer" .308 barrel, they got the functionality desired.

Yes, you are also correct, original Inglis 8mm bolts were used at first (type proofing), and later new-made "L4" bolts are fully interchangeable to my knowledge. And too, both original Inglis 8mm extractors and all other "7.62mm" extractors, no matter where made, are functionally interchangeable to my knowledge.

Warren W. may have a salient commentary on the Inglis angle.......and Peter may have to add anything I missed....
-TomH

[Peter Laidler]

All I can add is that some of our 7.62mm L4 breech blocks were marked 7.92 as were some of the extractors. The Trial;s team Warrant Officer, WO1 Fogwell died a couple of years ago. I wish I'd spoken to him at greater length. He was scathing about the A1 gun magazines, the HOD and the lack of magazine lip support (the body inserts) but all that was soon corrected. He called the L4A4 '.....the Bren gun at its finest'