Green Mace as an anti-tank weapon?

So, during the late 1950s, the UK experimented with a heavy AA gun codenamed "Green Mace".
It was a very capable weapon, and was only really canceled due to the introduction of early SAMs.
During testing, Green Mace apparently demonstrated a fire rate of 96 rounds per minute, which is mind blowingly high for a 102mm heavy AA gun. The gun itself had a range of about 4-5 miles, and fired folding fin discarding sabot ammunition. It should however, be noted that the weapon required a 15 minute reloading time, alongside 2 trailers for ammo and power.
Now, 3 what-if questions:

1. Could Green Mace have been used as a heavy anti-tank gun? How feasible would this even be?

2. Could Green Mace have been mounted on a tank (centurion on conquerer hull)? Presumably, if the something like the FV4005 exists, then something like this could too. The only real problem I can see with this is its constant need for power and ammunition.

3. If approved and put into service, how could this effect Soviet armored/military doctrine? Would we see more Soviet heavy tanks or a earlier helicopter gunship, or something entirely different?

I can't see a weapon like this having a change in the strategic balance of power, but considering it fires 102mm discarding sabot ammo at 96 RPM, it seems like a pretty good system on paper.

220px-Green_Mace_-_overall.JPG

Green Mace^

(stats and picture from Wikipedia)
 
The Conqueror was already developed as the 'answer' to Soviet heavy tanks like the T-10 and IS-3 and its 120mm gun would have been just fine. But to mount a weapon like this and its ammo hoppers, you'd need something like the FV-4005 series and a turret like theirs to fit it

WSY0WfM.jpg


http://www.tanks-encyclopedia.com/coldwar/UK/fv4005-stage-i-ii

Which is just a tad impractical to say the least. And indeed there was a plan to put the Green-Mace gun in this thing with this kind of turret set up. But really its not going to be too needed, the East and West were both thinking in terms of nuclear weapons being lobbed around like pound cakes in any future conflict so anything like this would have been of little use in a nuclear exchange.
 
It was a good AA gun for it's day but, divorced from it's director, it is a one trick pony. A good tank ROF is useful but there is a practical maximum which is the rate of target acquisition. If it takes 3 seconds to acquire the next target then all you need is to have a round ready to go once every 3 seconds and a 3 second acquisition is more of an aspiration than a reality. With twin 28 round drums you have a useful tank battle capacity and the tank engine can power the beast, as long as you don't want to drive around at the same time. Then there is the issue of type of round as you can change once the drum is loaded. HESH all round? Possibly in a casemate mounting? A sort of full auto Tortoise. Especially in the 120mm version.
 
The Conqueror was already developed as the 'answer' to Soviet heavy tanks like the T-10 and IS-3 and its 120mm gun would have been just fine. But to mount a weapon like this and its ammo hoppers, you'd need something like the FV-4005 series and a turret like theirs to fit it

WSY0WfM.jpg


http://www.tanks-encyclopedia.com/coldwar/UK/fv4005-stage-i-ii

Which is just a tad impractical to say the least. And indeed there was a plan to put the Green-Mace gun in this thing with this kind of turret set up. But really its not going to be too needed, the East and West were both thinking in terms of nuclear weapons being lobbed around like pound cakes in any future conflict so anything like this would have been of little use in a nuclear exchange.
Thats true. I also didn't really take nuclear weapons into account, so oh well.
 
Could be a decent naval gun though. Since being ship mounted solves all of its issues. The shell itself isn't really suited to shore bombardment but if it were developed to use new shell types it may survive quite a while in navy servce. Probably even get some exports too.
 
Could be a decent naval gun though. Since being ship mounted solves all of its issues. The shell itself isn't really suited to shore bombardment but if it were developed to use new shell types it may survive quite a while in navy servce. Probably even get some exports too.

from Tony Williams, gun guru

Battle Flight contains a description of the various AA gun projects of the 1950s, including automated versions of the existing 3.7 inch guns, a 4.26/3.2 inch (108/81 mm) squeezebore gun (a barrel for which still survives), the exotic Green Lizard (a gun-launched guided missile carrying submunitions), and the Green Mace. The Green Mace project consisted of three different guns: prototype 4 inch and 5 inch rifled guns (102 mm and 127 mm), and the planned service 5.68 inch (144 mm) smoothbore gun. The projectile was to consist of a long, sub-calibre, fin-stabilised discarding-sabot HE shell, with a muzzle velocity of 6,000 fps (1,829 m/s). The 4 inch and 5 inch guns were built and tested in 1954 and 1955, achieving short-burst rates of fire of 96 rpm and 75 rpm respectively. Ammunition was fed from two rotary magazines, one on each side of the gun, which elevated with it (similar systems were used in the American Skysweeper 75 mm AA gun and in the French AMX-13 light tank). Each magazine contained 14 rounds, so would need frequent replenishing in action. The barrels were water-cooled. The gun systems, mounted on wheeled trailers, were massive; the 4 inch version weighed 28 tons while the ultimate 5.68 inch was expected to weigh 62.5 tons - but it was never built, the project being cancelled in favour of guided missiles in 1954, though test firing of the prototypes continued for several years.

I have examined a sectioned 5 inch Green Mace round at Shrivenham; the case measures 127 x 690R x 172 rim and although the headstamp is faint it clearly includes "5 INCH".

Meanwhile, Vickers had been developing an automatic 4 inch naval gun. This gun was based on an experimental land service "X1 Medium AA Gun" which was test-fired in 1956. This was not the same gun as the Green Mace, since it used a different loading system - through the gun trunnions and fed by a couple of fixed hoppers on either side of the gun holding 28 rounds each. The rate of fire was 40-50 rpm. The naval gun was designated Mark Q, the single-barrel mounting the Mark N(R) or Vickers Universal Mount. The gun was rejected by the Royal Navy, in part because of the lack of a water-cooled barrel, but it was sold to Chile to arm the two Almirante class destroyers.

The Mark Q gun was originally designed around the 102 x 730R x 150 ammunition used in the L45-calibre MK 19 (the Royal Navy's standard 4 inch gun at the end of World War 2), but before entering service was modified to take an L62-calibre barrel with a higher performance. One source states that the ammunition for the L62 measured 102 x 670R, which fits in nicely with the British round shown below, which measures 102 x 670R x 173. It also explains why this round has the following projectile markings: 102 MM QF HE 4" - putting the metric measurement first suggests a foreign customer. It therefore seems highly probable that this 4" round was used in the Vickers Mark Q gun in the Chilean destroyers.



Barrel life?

Water cooling on Green Mace, not on the Vickers
 
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