Semi-auto Bren new built receivers?

[Peter Laidler]

Just as a little aside to this thread where someone suggested that firing from an open bolt keeps the barrel and receiver cooler. Well............ It
n THEORY and in the most very marginal test lab practice this may well be true. But in real practice, the open bolt v closed bolt operation with respect to barrel cooling has no effect at all. The tubular barrel, while being open at each end during lulls in firing has no real effect on cooling the barrel. Of course it has some effect...., it must but only measurable using instruments

This scenario has been used as a student discusssion and classroom practice for years and years and while it's good academic stuff, there is no mileage in complicating a weapon mechanism to incorporate it - as was shown time and time again with the UK SA80 machine gun and rifle variants. To prevent cook offs, then yes. But even then, the time between cook offs diminishes as the barrel cools and even the cook offs don't re-heat the barrel sufficient............. anyway....., you get my drift!

[Vincent]

The exception being when the gun is mounted in the wing of an aircraft, like the Spitfire. It has hot air ducts to the gun bays in the wings to keep its open bolt Brownings warm.

[Peter Laidler]

And in the front turrets of a Lancaster, where the same guns are subject to freezing temps due to altitude and a ram-air effect.......................?

[Vincent]

Good question.

I think the main crew compartment of the Lancaster, including the front turret is heated.

The tail turret is not heated. (Its gunner had to wear an electrically heated flight-suit.) So, presumably the freezing problem was only with unheated forward facing guns.

I am saving this one for a retirement project.

Attachment 47869

[Peter Laidler]

Just a thought Vince, but when you retire there won't be enough .303" ammo available, .303" brownings don't like rubbish ammo (mind you, nor do our .300"'s either!) and your wallet will have a heart attack when you see the speed that the belts are being dragged through! I thought that the best bit is to see the links being spewed out!

[Brit plumber]

Good question.

I think the main crew compartment of the Lancaster, including the front turret is heated.

The tail turret is not heated. (Its gunner had to wear an electrically heated flight-suit.) So, presumably the freezing problem was only with unheated forward facing guns.

I am saving this one for a retirement project.

Attachment 47869

That's a handy photo for me Vince. That's the only other early MkII I've seen other than my own, the others I've seen are MkII* or early guns mod'ed to MkII*. Your photo shows the flush rivets that now I'm sure were only found on the MkII and not the dome heads of the MkII*. This is my long term project

[Vincent]

This is my long term project

How's the barrel jacket going? Let me know if you need any more dimensions.

I could use some photos of the inside of the receiver if you get a chance.

[Vincent]

Just a thought Vince, but when you retire there won't be enough .303" ammo available, .303" brownings don't like rubbish ammo (mind you, nor do our .300"'s either!) and your wallet will have a heart attack when you see the speed that the belts are being dragged through! I thought that the best bit is to see the links being spewed out!

I ran into a good deal of ammo a few years ago. Most is on Vickers cloth belts though. My biggest problem is finding links. They are hard to find over here.

[ActionYobbo]

I ran into a good deal of ammo a few years ago. Most is on Vickers cloth belts though. My biggest problem is finding links. They are hard to find over here.

cant help you with the links but I could use a few cloth belts

[Brit plumber]

I'd forgotten all about that, I'll be back home next week for xmas so its a good time to take some photo's. The barrel jacket is one of those jobs I'll get to when time permits. I work away from home so when I do manage to get back for a week the OIC House usually has a list of S*** jobs for me to do. That or I need to spend what the wife would call 'Quality time' with her, I'd call it time not spent in my garage!