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Does anyone have any info on how Breda produced the fluted chambers on the 30-06 Bren conversion ? Someone that has one of the recent imported parts sets let me chamber cast the barrel and it has heavy fluting.
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Aren't those a hammer forged barrel?Quote:
Originally Posted by cal50
Bet the spent brass looks ... interesting!
Russ
You've never seen anything coming out of an HK 33 or 91 or 93? Or a G3? They all have fluted chambers too, the MP5 should have too. They all allow positive extraction but are very hard on brass. They weren't meant to supply reloaders with brass.Quote:
Originally Posted by RASelkirk
Hoping to learn any history or manufacturing details on the gun.
I am sure Breda engineers did it for a reason......
But does anyone know how the fluted chamber was/is produced, i.e. with the internal flutes to the chamber? A "traditional method" of producing internal slots within a hole is to use a process known as "broaching" and in this application it is possible that all the flutes were "broached" at the same time or one flute at a time.
If you read the procedure for forming a hammer forged barrel, a rotating mandrel is withdrawn and rotated as the barrel is formed. The final part forms the chamber. Or words to that effect, once you read it you'll see the picture in your head... This will help... The More You Know: Cold Hammer Forging (CHF) -The Firearm BlogQuote:
Originally Posted by Flying10uk
I have broached a lot of things but doing a 30-06 chamber flutes would be a tough one. I don't see any room to press a long broaching to get the depth or room for chips.
Hammer forging is not likely since the mandrel has to rotate with the rifling to remove and no way with straight flutes in the chamber.
I think the stub I cast was dated 1959.
Quote:
Originally Posted by browningautorifle
No, I didn't even know this type of chamber existed. What would be the purpose? Obviously, the mfg'ing expense would be much higher so I must assume some type of benefit...
Russ
Flutes aid in extraction / brass does not stick to chamber.
HK's have a roller delayed system that is more like a transmission than a locked bolt system and need a fluted chamber for function.
POF I think has a patent on their E2 chamber and they notch the neck area in four places to enhance extraction and reliability.
This would be easier to apply to a Bren 06 barrel IMHO.
POF-USA: E² Extraction Technology Demo - YouTube
POF Behind The Brand - Groundbreaking E2 AR Technology - YouTube
These have been around as long as we have...Not new. They aid in extraction.Quote:
Originally Posted by RASelkirk
How do you think the flutes were produced then if they weren't broached or forged?Quote:
Originally Posted by cal50
If the stub that you cast is dated 1959 I guess that it would be in the era of "spark erosion technology" but I don't know how good the process would be in this application, i.e. a gun chamber.
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That is why I wondered if they broached the flutes individually but as you suggest it is deep.Quote:
Originally Posted by cal50
Usually in firearms with violent extraction cycle, to prevent cases sticking in the chamber or rim torn off.Quote:
Originally Posted by browningautorifle
Yes. Interestingly...there was a discussion over in the M14 forum about them being the very thing that tears off a base. I don't agree though. Like you say, to prevent sticking.Quote:
Originally Posted by Daan Kemp
Quote:
Originally Posted by Flying10uk
The sharp edges appear to be cut , like broaching but the end angles into the chamber would be almost impossibly cut at the sharp angle.
If I had a spare barrel to keep I would prefer to section it and have a closer look.
It might be an insert not visible externally.
Some M60 barrels used a hardened insert for wear.
Maybe its something similar , I have no idea.
M60 Stellite Liner: A Closer Look - YouTube
When I saw that fluted chamber I couldn't help thinking of all the unburned propelland and carbon that would end up in there. Just remember all that diamond hard crusted-on carbon fouling that you used to spend hours cleaning off of the gas parts while sat on the ranges. That same crap will be encrusting the fluted chamber. Just my view of course because it's got to go somewhere and gas ALWAYS takes the line of least resistance
Our early GPMG's had stellite lined barrels for the first 6" or so. The problem was that the stellite was good, but it just eat the barrel FORWARD of the stellite liner!
The Soviet SVT 40 used a fluted chamber (do not believe full length but still fluted) not all used the fluted chamber but a large number did use it.