Machine Guns and Cannons (Ground, Vehicle, and Aircraft Mounted Weapons)

[rickshaw]

The Germans preferred to decrease calibre along the whole barrel length.  Technically better but far more difficult to produce.  The British instead opted for the "Little John" attachment, which screwed on the muzzle of the 2 Pdr.  It saw service late in the war on Armoured Cars.  However, while its increased armour penetration was appreciated, the fact that HE couldn't be fired with it on meant that one car in each troop had it removed.  It wasn't until after the war that a HECR (HE Composite Rigid) round was developed for it (and it only had the equivalent effect to a 20mm HE round).  As the British had decided to go down the path of APDS anyway, the matter was considered moot, particularly after the decision to arm the Saladin with the 76mm low pressure gun, rather than Pipsqueak, the last of the Gerlich squeeze bore guns (and end of the line for the excellent 2 Pdr).

[dy031101]

Thank you for the answers.  

Okay, let's leave the Matilda completely aside now (and once again assuming the 85mm to be nowhere in sight for the sake of the argument).

If I'm reading Wikipedia entry correctly, APCR is available to the F-34...... would an APDS projectile have furthered the AT performance a bit more?

[rickshaw]

Thank you for the answers.  

Okay, let's leave the Matilda completely aside now.

If I'm reading Wikipedia entry correctly, APCR is available to the F-34...... would an APDS projectile have furthered the AT performance a bit more?

Yes but accuracy would have decreased.   One of the problems that was found and not cured in APDS until well into the 1950s was that it suffered from significant dispersion over range.  This was caused by the sabots failing to separate cleanly, producing yaw.

I'd just increase the barrel length and chamber size and stick with standard AP/APC/APCBC.  It worked quite well for the Germans with their 75mm KwK series of guns.  You could add APCR/APDS later.

[dy031101]

The British attempted to up-arm the Matilda but found they needed a new turret and that needed in turn a larger turret ring to absorb the recoil, with the result they ended up having to put a riser on the hull top to allow the ring to over-arch the tracks.

I take this:

http://mailer.fsu.edu/~akirk/tanks/GreatBritain/GB-Matilda2-6pdr.jpg

to be the result you're talking about w.r.t. the Matilda?

The turret looks a lot like that of the Cromwell...... is this indeed where the timeframe of the experiment was at?  Did it allow for more crew space as well, or is crew space still predominantly determined by the opening on the hull?

(Disclaimer: yes, I suspect without any concrete knowledge that newer designs were already rolling out of factories, therefore reducing the necessity of this experiment, by the time it actually took place.  I just found it interesting.  )

[rickshaw]

Yes, thats the prototype that I was thinking of.  Apparently built in 1942, the turret actually predates the Cromwell and is actually a little bit smaller than the Cromwell's.    I suspect the Cromwell was in the planning stage and they simply modelled it on that design.  The Tilly while a very good 1939 design was by then simply at the end of its life because it wasn't large enough to be upgunned.   It was though, exactly the right balance of firepower, protection and weight for the SW Pacific.  The Australian Army kept them in operation until the mid-1950s, despite having first M3 Grant/Lees, then  Churchills and even Centurions by then.

[dy031101]

Yes, thats the prototype that I was thinking of.  Apparently built in 1942, the turret actually predates the Cromwell and is actually a little bit smaller than the Cromwell's.    I suspect the Cromwell was in the planning stage and they simply modelled it on that design.  The Tilly while a very good 1939 design was by then simply at the end of its life because it wasn't large enough to be upgunned.

Googling relevant terms yielded the notions that the turret actually came from the A24 Cavalier cruiser tank, that new production Matildas were intended only for armies of Australia and USSR by the time this idea was tried, and that the British insisted the production of the 6-pounder wouldn't be made at the expense of the 2-pounder.

In any event, production of the 6-pounder didn't begin until November 1941, and it was only in spring 1942 when the new gun reached frontline units, so it's probably safe to assume that the tank guns that were built would all go to the Valentine and the cruisers.

[dy031101]

In the past, most tank gun rounds have carried substantially less HE than a comparable calibre artillery weapon because of the increased stresses involved with firing them at a higher muzzle velocity.

Curiosity- compare the HE round from the WWII US 75mm howitzer (as in the one used by, for example, M8 HMC) with that from the French DEFA F1 or Cockerill Mk.3; which one is more powerful?

[rickshaw]

That would be a bit comparing apples and oranges.   A howitzer, by tradition has a lower MV than a gun, relying upon elevation to get increased range  (by definition, guns cannot elevate above 45 degrees whereas howitzers can).   So, generally a howitzer fires its round at a lower velocity than does a gun of the same calibre.   The French CN 75-50 75 mm gun (I assume that is the "DEFA F1") had a MV of 925 m/s.  The 75mm Howitzer M8 had a MV of 381 m/s.  You could have looked it up on Google, you realise?

[dy031101]

The French CN 75-50 75 mm gun (I assume that is the "DEFA F1") had a MV of 925 m/s.

No, I mean what these stuff is for.

It's the main armament of the AML-90 armoured car and, IIRC, Norway's upgunned M24 tanks, so I thought this low-pressure gun should be a pretty widespread stuff, but the gun performance seem rather obscure to me.

Cockerill Mk.3 fires a HE-T round at 700m/s.  I don't know how much explosive the shell has or how destructive the combination would be compared to the that of the 75mm howitzer.

[DarrenP]

BREN/L4 series

When my unit converted from L4 to LSW I was decidedly underwhelmed by the new weapon and saw The L4 out shoot the LSW more than once. I do wonder if the L4's could have been converted again to 5.56mm and would the Brens action have been light enough to function. The magazine feed issue may have caused problems.

[rickshaw]

The Bren was most accurate in its .303in version.  I've seen diggers get consistent 3 inch groups at 200 metres with those.  In the L4, the accuracy decreased, down to about a 5 inch group at that range.  The .303in version consistently "threw" its rounds high and to the right and a well versed soldier could take advantage of that.  When they changed the barrels to 7.62x51mm the consistency was lost, perhaps deliberately (one of the major criticisms levelled at the Bren was that it was simply too accurate to make a good infantry MG).

Converting it to 5.56x45mm could have been done but you'd have ended up with an over-heavy weapon.  It would have been steady as a rock but as I've alluded to, that isn't necessarily something you need or want in a section machine gun.  Then there was the magazine feed.  Excellent for ammunition conservation but really bad when you wanted a high volume of continuous fire.  It was one of the features which gained favour for the weapon when it was first adopted - the British Army disliked being profligate with ammunition when engaged on "Imperial Policing" duties, often far from home.

The FN-Minimi OTOH is the weapon the British Army should have adopted instead of the LSW.   I know they now use it, after the initial lessons of Afghanistan had been absorbed.  There is unfortunately nothing which replaces firepower when its needed.

[Maverick]

I think the L86 was an offshoot of that trend to develop a 'heavy barrel' version of the standard assault rifle as an LMG.  I, for one, am glad the ARA didn't go down a similar route with the Steyr HBAR and instead chose our Minimi variant. 

Coupled to the use of the L4 in many units, it would, no doubt, have seemed to be a good weapon to issue to replace the L4.  The reality is, however, that the British Army isn't engaged in Imperial Policing duties anymore, instead fighting a protracted counter-insurgency campaign where, as Brian has alluded to, firepower is rather more important.

I have seen the Minimi on issue to British forces (notably the Parachute Regt and RM Cdo in addition to the SAS), so it would suggest that in some shape it is available for issue.

Regards,

Mav

[rickshaw]

AIUI, the minimi is now on general issue but I'm quite willing to be corrected.

The Bren, in all its forms is a superb full power calibre LMG.  Problem is, it was designed when the philosophy was that you required an LMG that while providing greater firepower than a normal rifle, allowed controlled fire which conserved ammunition.  Imperial Policing columns were often at the end of very tenuous supply lines and so conservation of resources was important, both from a military and an economic point of view.   The bean counters wanted Empire on the cheap (nothing really has changed, has it?).

While the supply system has markedly improved for the British Army, they still can't afford to be as profligate as the US Army is with logistics.   Hence the preferences for the LSW which is BTW a popular and quite good weapon according to accounts, being used more as a marksman's weapon than an LMG (the long barrel and bipod make it very accurate at extended range apparently).

[Maverick]

Whether the British Army's logistics system is good or otherwise isn't really the point, in my opinion. 

A small unit (ie: section size), somewhere within places not to be named & nasty to boot might very well appreciate the suppressive capabilities of the Minimi (or any other proper LMG) for that matter. 

It's all well and good having a weapon capable of a marksman type role (the US & Israelis have both fielded revamped weapons of that nature) but to expect a rifle capacity magazine-fed weapon to supress is quite naive in my opinion. 

After all, the rest of the section has the same calibre (and magazine capacity), so all you really have is a heavier assault rifle.  The optics are the same and beyond a bipod & longer barrel the differences between the L85 & 86 are neglible.

Something like the Minimi on the other hand, allows effective suppressive fire to be directed at an area, rather than a few squirts from a warmed over rifle.  That's basic small unit tactics regardless of whether they're British or Australians. 

The section is there to support the LMG and it's an accepted part of those tactics that the 'firepower' of the section will be the LMG, not a few rifles.

Regards,

Mav

[Weaver]

While the supply system has markedly improved for the British Army, they still can't afford to be as profligate as the US Army is with logistics.   Hence the preferences for the LSW which is BTW a popular and quite good weapon according to accounts, being used more as a marksman's weapon than an LMG (the long barrel and bipod make it very accurate at extended range apparently).

This might be out of date info now, but my understanding was that one of the two LSWs in a section was being replaced by a Minimi Para (short barrelled, folding stock version) for volume firepower, while the other LSW was kept for it's accuracy. However they've now bought a proper 7.62mm "Sharpshooter"  (as opposed to "sniper") rifle, the L129A1, so perhaps that has replaced the other LSW now, at least in units in Afghanistan?

I've always like the Singaporean Ultimax 100: 100 round drum or M-16 mag seems a good compromise between the various limitations of boxes and belts.