Zimi Model

[Mossie]

The quad mount is still a very wide, unwieldy thing to mount on a vehicle though. Don't forget the 40mm Bofors is a clip-feed, so this thing needs a crew of a dozen, all with somewhere to stand and move, whatever bearing it's rotated to. The diameter of the fixed shield gives you some idea of just how big the platform would have to be if the whole thing was firing from the back of a truck. Since all the fire-control and ammo supply would be off-mount anyway, it's hard to see why you wouldn't just have two twins, on smaller and more manageable platforms, using the same set of support vehicles.

Width wise, it could be solved by having it stowed sideways on the move. The Vomag has sides that fold down to give a wider platform when operating, that could be the case too.

[Weaver]

The quad mount is still a very wide, unwieldy thing to mount on a vehicle though. Don't forget the 40mm Bofors is a clip-feed, so this thing needs a crew of a dozen, all with somewhere to stand and move, whatever bearing it's rotated to. The diameter of the fixed shield gives you some idea of just how big the platform would have to be if the whole thing was firing from the back of a truck. Since all the fire-control and ammo supply would be off-mount anyway, it's hard to see why you wouldn't just have two twins, on smaller and more manageable platforms, using the same set of support vehicles.

Width wise, it could be solved by having it stowed sideways on the move. The Vomag has sides that fold down to give a wider platform when operating, that could be the case too.

But then the barrels would be sticking out sideways...

[Mossie]

Have them at full elevation. Wiki would have me believe it's 90⁰, not sure about that. Might be possible to engineer in a stowed position.

[Wardukw]

On the practical side of things this idea is stupid ,,it's heavy and not something for tight spaces and as Jon said ,,much better if it was on a trailer ,,,but lets go into mega nerdy brain thought territory 
Ok first off lets think of this in the modern time line ,,apocalyptic waste land sort of thing ,, Mad Max kinda deal but built by a well established city for convoy protection or whatever comes to mind which would need something with that much fire power ,,,yeah we could get into the very technical side such as where the ammo is coming from and so on and so forth but there's no real fun in that is there ? .
This is Wiffy World so lets keep it there ,,it also makes my life easier and me brain less cloudy 
Frist off .. the truck ,, Alvis unipower m series mh 6600 .. 24 ton payload and fecking huge .. it comes in different chassis lengths too ..so say these guys got a long wheel base version ,,Alvis did build a prototype 12x8 for the Indian government as a potential missile carrier  but it wasn't accepted,,a massive shame as it was very cool . ,,but i'll stick with the 8x8 as it's more common and there in the US and Canada  and they are used in Europe by some firms to tow 300ton loads ..those trucks can weight as much as 70+ tons or more   
The cooling problem  Jon mentioned ,,weill i have the perfect thing to solve that ,, Evans waterless coolant ,,handles temps over 180°C or 356°F with ease ,,say they found a way to make it from samples or containers they found ,,or they found a massive stock pile of it ,,who knows .. anyways the stuff would stop the heat dead and yep it would take some good engineering to get the system to work but any good mechanic who knows his salt would get it figured ..setting up an electric water pump isn't that hard at all ..i've done it my self on of my Capris .
Mossie said about transporting it sideways which makes sense for sure ,,one idea i've had is to split the whole deal up ..loose the layout you see in the pics and mount the guns on a brand new base .. a rectangular one to work better with the truck's  deck which would be custom built and could very easily hand over the back of the back wheels by a good couple of metres  ,,so by mounting one set of guns at the rear and one set closer to the front you could transport the guns by having em nearly interlock with each other as the guns themselves ain't all the long really or they could just by muzzle to muzzle if the space allows .
I  could go on and on but i'm sure you blokes get the idea here .

[Weaver]

In other words, split up the quad mount into two twins to fit better on one big truck rather that two regular trucks...    

[zenrat]

Presumably the British equivalent would be a QF 2 Pounder Mk.VIII Chicago Piano mounted on the back of a Scammell?

[Mossie]

Yes. Want one of those. 

[Wardukw]

Presumably the British equivalent would be a QF 2 Pounder Mk.VIII Chicago Piano mounted on the back of a Scammell?

You mean then 2pdr Pom Pom gun Fred ?
And if so ,,hell yes!! ..most definitely   

[Weaver]

Did a search for pics of Pom Pom guns on trucks. Didn't find any (of the WWII type), but did find these glorious 1960s toys, all of which are described as "Pom Poms" but all of which seem more modelled on the Bofors, although without any particular regard to scale...

[Charlie_c67]

Pom-Pom? Looks more like Kaboom-Kaboom! Would make an excellent OO/HO railway gun.

[Weaver]

Pom-Pom? Looks more like Kaboom-Kaboom! Would make an excellent OO/HO railway gun.

I mean, technically, they're a Kaboom-Kaboom, a Kaboom-Kaboom-Flash, and a Kaboom-Kaboom-Kaboom-Kaboom...

[Wardukw]

I did find a pic of a pom pom mounted on a rail carriage and another on a two wheeled cart with wagon wheels ,,, i'm not surprised that it's not vehicle mounted as these are pretty big and heavy weapons and that not including the mounts either ,,at 40mm even the ammo boxes are rather large ..i could see a single mount being mounted to a track ,,a twin would need a big-ish truck ,,say 6ton and up ,,but a quad mount ,,oh that would need a big truck for sure ,,12ton class ,,minimum .

[Mossie]

And the eight gun Chicago piano...

[Wardukw]

If ideas had to be made into reality then i wouldn't use the pom pom gun at all if 40mm was the guns that had to be used ,,i'd just go with Bofors guns .. would take up less space since the guns are fed from the top at the back of the gun ,,not the sides and it wouldn't surprise me if they also had a higher rate of fire annnnnnd ,,a much better selection of ammo for the guns too .

[Old Wombat]

QF 2-pounder Mark VIII
Calibre: 40 mm L/39
Shell Weight: 2 lb. (980 g) or 1.8 lb. (820 g) for High-Velocity (HV) round
Rate of Fire: 115 rpm fully automatic
Effective Range: 3,800 yards (3,475 m) or 5,000 yards (4,572 m) HV
Effective Ceiling (HV): 13,300 feet (3,960 m)
Muzzle Velocity: 2,040 ft/s (622 m/s) or 2400 ft/s (732 m/s) for HV

Octuple 2-pdr Pom-Pom (Chicago Piano);


Quad 2-pdr (40mm) Pom-Pom for direct comparrison to quad 40mm Bofors;


Bofors 40 mm L/60 gun
Caliber   40 mm (1.57 in)
Shell weight   0.9 kg (2 lb 0 oz)
Barrel length   2.25 m (7 ft 5 in)
Rate of fire   
    Low elevation angles:     140 rounds/min
    High elevation angles:    120 rounds/min
Maximum firing range   7,160 m (7,830 yd)
Muzzle velocity   2,800ft/s (850m/s)–2,900 ft/s (880m/s)

Quad 40mm Bofors;