Multiple Weapons for Armoured Vehicles

[rickshaw]

(Right this is the discussion sparked by CBE's Centurion Street Fighter - Chris)

Very interesting.  A short barrelled 20 Pdr would be a bit of a beast, I think.  If the charge in the shell wasn't reduced you'd get a hell of a muzzle blast from the unburnt powder. The muzzle-brake will reduce the recoil but not the blast.  Not the best idea in an urban environment where you'd have to have close support from your own troops.   I like the Ferret turret.  They did something similar with the ARVs in Vietnam, giving the commander a box-like shield for his MG.  The "anti-climbing" wire is an interesting addition.  I'd think I'd have preferred some fencing, rather than a single strand.  The rear "grenade launchers" seem to cover only the right rear quarter.  What about the other side?

While the AVRE was specifically an Army vehicle, there would be no reason why the RM Commandos couldn't have adopted it.  It would have been like their adoption of the Centaur Close Support which was originally an Army tank with its 95mm Howitzer.  The 165mm gun would have made better sense in a vehicle who's role was going to be close support during an assault landing.  The 165mm HESH was a fearsome round, packing by all reports a hell of a punch.   Its major problem was low muzzle velocity which didn't endear it to long range AT gunnery.  

[Weaver]

I was going to suggest boring out the short 20pdr by 4mm to take 25pdr field gun ammo, but actually the latter's case is so much narrower that by the time you'd finished modding the gun, it would probably have been easier to start with a clean sheet of paper. Mind you, that in itself isn't a bad idea, i.e. an all-new turret-mounted gun that fired 25pdr ammo. You could probably fit that into a Saladin, never mind a Centurion. It would be a bit like the UK equivalent of the short French 90mm weapon.

[kerick]

hi kerick

you mean like this

I mean exactly like that! Awesome!

[rickshaw]

I was going to suggest boring out the short 20pdr by 4mm to take 25pdr field gun ammo, but actually the latter's case is so much narrower that by the time you'd finished modding the gun, it would probably have been easier to start with a clean sheet of paper. Mind you, that in itself isn't a bad idea, i.e. an all-new turret-mounted gun that fired 25pdr ammo. You could probably fit that into a Saladin, never mind a Centurion. It would be a bit like the UK equivalent of the short French 90mm weapon.

Except the 25 Pdr fires a separated case round and those are never popular inside turrets.  A new weapon would be best, one with a cased round, making loading simpler.  25 Pdr would make an interesting choice.  Of course, they could have resurrected the abortion of a gun, the Ordnance QF 95-mm infantry howitzer, which used IIRC a 25 Pdr breech, mated to a new 95mm barrel.  As Ian Hogg remarked, while it was very unsuccessful, they made thousands of them if the pictorial evidence is to be believed of them arraigned in gun parks.

[crudebuteffective]

Very interesting.  A short barrelled 20 Pdr would be a bit of a beast, I think.  If the charge in the shell wasn't reduced you'd get a hell of a muzzle blast from the unburnt powder. The muzzle-brake will reduce the recoil but not the blast.  Not the best idea in an urban environment where you'd have to have close support from your own troops.  ....................  The rear "grenade launchers" seem to cover only the right rear quarter.  What about the other side?

While the AVRE was specifically an Army vehicle, there would be no reason why the RM Commandos couldn't have adopted it.  It would have been like their adoption of the Centaur Close Support which was originally an Army tank with its 95mm Howitzer.  The 165mm gun would have made better sense in a vehicle who's role was going to be close support during an assault landing.  The 165mm HESH was a fearsome round, packing by all reports a hell of a punch.   Its major problem was low muzzle velocity which didn't endear it to long range AT gunnery. 

The muzzle brake did give me some second thoughts due to the blast (great minds think alike hey)

on the rear left is  the comms telephone conecting the supporting troops with the tank crew ( real world fitted to all british tanks since 49) along side is a single searchlight for use by supporting troops To sweep windows etc hence no the grenade launchers on that side

THE centurion AVRE 165 didnt appear till 65 so didnt fit well with my marine timeline and i thought the 60lb shell fired by that might be a bit "over the top" (plus i have already made one)

[Weaver]

I was going to suggest boring out the short 20pdr by 4mm to take 25pdr field gun ammo, but actually the latter's case is so much narrower that by the time you'd finished modding the gun, it would probably have been easier to start with a clean sheet of paper. Mind you, that in itself isn't a bad idea, i.e. an all-new turret-mounted gun that fired 25pdr ammo. You could probably fit that into a Saladin, never mind a Centurion. It would be a bit like the UK equivalent of the short French 90mm weapon.

Except the 25 Pdr fires a separated case round and those are never popular inside turrets.  A new weapon would be best, one with a cased round, making loading simpler.  25 Pdr would make an interesting choice.  Of course, they could have resurrected the abortion of a gun, the Ordnance QF 95-mm infantry howitzer, which used IIRC a 25 Pdr breech, mated to a new 95mm barrel.  As Ian Hogg remarked, while it was very unsuccessful, they made thousands of them if the pictorial evidence is to be believed of them arraigned in gun parks.

The L11 and L30 120mm guns in British tanks use separate-loading ammo: if it's practical for a round that big, surely it'd be a doddle for a 25pdr? For a fire-support weapon, separate loading gives the possibility of reduced charges for short-range, high-angle fire, which would be very useful if the gun could be given more elevation than a typical tank gun. That shouldn't be difficult, given the smaller size and recoil force of the 25 pdr.

[crudebuteffective]

from a british govt point of view the main thing to think about with simply cutting down a 20pdr  would be................. CHEAP!

[rickshaw]

I was going to suggest boring out the short 20pdr by 4mm to take 25pdr field gun ammo, but actually the latter's case is so much narrower that by the time you'd finished modding the gun, it would probably have been easier to start with a clean sheet of paper. Mind you, that in itself isn't a bad idea, i.e. an all-new turret-mounted gun that fired 25pdr ammo. You could probably fit that into a Saladin, never mind a Centurion. It would be a bit like the UK equivalent of the short French 90mm weapon.

Except the 25 Pdr fires a separated case round and those are never popular inside turrets.  A new weapon would be best, one with a cased round, making loading simpler.  25 Pdr would make an interesting choice.  Of course, they could have resurrected the abortion of a gun, the Ordnance QF 95-mm infantry howitzer, which used IIRC a 25 Pdr breech, mated to a new 95mm barrel.  As Ian Hogg remarked, while it was very unsuccessful, they made thousands of them if the pictorial evidence is to be believed of them arraigned in gun parks.

The L11 and L30 120mm guns in British tanks use separate-loading ammo: if it's practical for a round that big, surely it'd be a doddle for a 25pdr? For a fire-support weapon, separate loading gives the possibility of reduced charges for short-range, high-angle fire, which would be very useful if the gun could be given more elevation than a typical tank gun. That shouldn't be difficult, given the smaller size and recoil force of the 25 pdr.

The L11 and L30 use bagged charges.  They weren't popular when they were introduced.   Remember, I'm not talking about practicality but rather popularity.  Long use has proved them to be practical (although the Americans and Germans for a long time didn't like them and preferred to work out the problems with combustible cases).  The main object to separate loading of cases or bagged charges is that they take longer than a fixed case round to load.  There is also the danger of powder being spilt inside the turret, from holed bags.   As it is, the only safe way to store the charge bags in the Chieftain and later Challenger was to use a water jacketed magazine which automatically floods the charges (hence rendering them useless) if the turret is penetrated.

As you point out, separated cases does give the advantage of variable velocity and hence range. So do bagged charges.  In a direct fire weapon such as a close-support howitzer in a tank, you don't really need variable charges but you do need to be able to reload as fast as an AT or tank gun using a cased round.

[Old Wombat]

I have a personal affection for the old 25-pounder - not from experience, just from what I've heard about its popularity & effectiveness.

So, given that there were still seperate-cased rounds being made for it (or had just, or were just about to stop being made) in this era, why not have a tank mounted demolition variant using a purpose-built cased round developed from the original?

Not saying it would be a doddle but I can't believe that it would have been that hard.



Guy

[Weaver]

I was going to suggest boring out the short 20pdr by 4mm to take 25pdr field gun ammo, but actually the latter's case is so much narrower that by the time you'd finished modding the gun, it would probably have been easier to start with a clean sheet of paper. Mind you, that in itself isn't a bad idea, i.e. an all-new turret-mounted gun that fired 25pdr ammo. You could probably fit that into a Saladin, never mind a Centurion. It would be a bit like the UK equivalent of the short French 90mm weapon.

Except the 25 Pdr fires a separated case round and those are never popular inside turrets.  A new weapon would be best, one with a cased round, making loading simpler.  25 Pdr would make an interesting choice.  Of course, they could have resurrected the abortion of a gun, the Ordnance QF 95-mm infantry howitzer, which used IIRC a 25 Pdr breech, mated to a new 95mm barrel.  As Ian Hogg remarked, while it was very unsuccessful, they made thousands of them if the pictorial evidence is to be believed of them arraigned in gun parks.

The L11 and L30 120mm guns in British tanks use separate-loading ammo: if it's practical for a round that big, surely it'd be a doddle for a 25pdr? For a fire-support weapon, separate loading gives the possibility of reduced charges for short-range, high-angle fire, which would be very useful if the gun could be given more elevation than a typical tank gun. That shouldn't be difficult, given the smaller size and recoil force of the 25 pdr.

The L11 and L30 use bagged charges.  They weren't popular when they were introduced.   Remember, I'm not talking about practicality but rather popularity.  Long use has proved them to be practical (although the Americans and Germans for a long time didn't like them and preferred to work out the problems with combustible cases).  The main object to separate loading of cases or bagged charges is that they take longer than a fixed case round to load.  There is also the danger of powder being spilt inside the turret, from holed bags.   As it is, the only safe way to store the charge bags in the Chieftain and later Challenger was to use a water jacketed magazine which automatically floods the charges (hence rendering them useless) if the turret is penetrated.

As you point out, separated cases does give the advantage of variable velocity and hence range. So do bagged charges.  In a direct fire weapon such as a close-support howitzer in a tank, you don't really need variable charges but you do need to be able to reload as fast as an AT or tank gun using a cased round.

Some of the rounds for the L30 use rigid combustible cases (still separate) IIRC. The separate cases for the 25pdr were brass, so surely that would be safer than bags since all you'd have to do is protect the open ends, which could be done by a well-designed ammo rack, rather than the whole thing?

You don't need variable charges in a direct-fire CS howitzer per se, but the latter is a rather niche weapon that tends to be used only be specialist units that are either available or not. Making it more versatile, by allowing it to function as conventional short-range artillery as well as a CS weapon makes it viable to deploy it with every tank unit, thus increasing the probability that some of them are in the right place at the right time.

If you've giving this street-fighting Centurion a smaller main gun with a higher elevation range, why not put a 20mm cannon next to it? That's another highly accurate weapon with limited side-effects which is useful in street-fighting: taking out the sniper on the top floor without killing the innocents cowering on the floor below, that sort of thing...

[Old Wombat]

25 pounder + 20 mm ..... Mmmmm, yummy!

[rickshaw]

The L11 and L30 use bagged charges.  They weren't popular when they were introduced.   Remember, I'm not talking about practicality but rather popularity.  Long use has proved them to be practical (although the Americans and Germans for a long time didn't like them and preferred to work out the problems with combustible cases).  The main object to separate loading of cases or bagged charges is that they take longer than a fixed case round to load.  There is also the danger of powder being spilt inside the turret, from holed bags.   As it is, the only safe way to store the charge bags in the Chieftain and later Challenger was to use a water jacketed magazine which automatically floods the charges (hence rendering them useless) if the turret is penetrated.

As you point out, separated cases does give the advantage of variable velocity and hence range. So do bagged charges.  In a direct fire weapon such as a close-support howitzer in a tank, you don't really need variable charges but you do need to be able to reload as fast as an AT or tank gun using a cased round.

Some of the rounds for the L30 use rigid combustible cases (still separate) IIRC. The separate cases for the 25pdr were brass, so surely that would be safer than bags since all you'd have to do is protect the open ends, which could be done by a well-designed ammo rack, rather than the whole thing?

That is a possibility, however you still need to remove the stopper in the end of the case before loading, which of course slows the loading sequence.  The use of a metal case is obvously better than bagged charges or even cardboard combustable cases from an incendiary viewpoint inside an armoured vehicle, being less prone to ignition from hot fragments if a penetration occurs (even so, water jacketed magazines were introduced by the Allies after 1943 in their vehicles make sure such ignition problems were reduced even further).

You don't need variable charges in a direct-fire CS howitzer per se, but the latter is a rather niche weapon that tends to be used only be specialist units that are either available or not. Making it more versatile, by allowing it to function as conventional short-range artillery as well as a CS weapon makes it viable to deploy it with every tank unit, thus increasing the probability that some of them are in the right place at the right time.

Most tanks, particularly Allied tanks after about 1944 were equipped to undertake indirect fire and act as extra artillery during heavy pre-attack "pepper-pot" bombardments.  The variable range of a howitzer isn't really all that useful, unless the mount can allow elevations to 45 degrees or higher.  Once you're that high, the variable charges really come into their own, allowing trajectories which come close than a direct weapon firing a reduced charge.   CS Tanks were distributed in the British Army (which were their real proponents) to every armoured unit, usually held in the Squadron HQ.  They were initially mainly intended to fire Smoke and as the war progressed, HE.  However, variable charges mean you have small bags of powder floating around in the turret, as charges are discarded.   Much easier and safer to have a fixed round, really.

If you've giving this street-fighting Centurion a smaller main gun with a higher elevation range, why not put a 20mm cannon next to it? That's another highly accurate weapon with limited side-effects which is useful in street-fighting: taking out the sniper on the top floor without killing the innocents cowering on the floor below, that sort of thing...

In most urban settings, 20mm can be as bad as large calibre HE round.  Afterall, the main function of a 20mm cannon is to use a HE round itself and a lot of splinters.   Personally, if I was designing a vehicle in the late 1950s-early 1960s, expressly for urban warfare I'd have one with a fixed casement, with a large calibre HE thrower in the centre, front (105mm or larger) with a high elevation and limited traverse.  On the two rear corners I'd have sub-turrets, both with a .50cal or one with a .50cal and the other with a .30cal.  Both are more than adequate to penetrate most walls, particularly at close range.   The main advantage of the .30cal would be for suppressive fire.  I'd have an electrified fence on the vehicle sides and rear.  A dozer blade on the front.  APers mine dischargers on all four corners, as the Germans did on the Eastern Front with S-mines.   A 2in bomb thrower in the cabin roof.  It's main protection though would have to be some hardy and well trained infantry, who made sure that no baddies got too close.

[Weaver]

I'm cutting out the quotes-in-quotes if you don't mind, since they're getting a bit cumbersome.

That is a possibility, however you still need to remove the stopper in the end of the case before loading, which of course slows the loading sequence. 

That was what I meant by a well-designed ammo rack. Either:

a) the closure of the case is combustible and the rack provides a solid cover or shield for it when it's stowed,

b) the case has a solid stopper which engages with the rack when you stow it, so that when you pull it out, the stopper stays in the rack.

You don't need variable charges in a direct-fire CS howitzer per se, but the latter is a rather niche weapon that tends to be used only be specialist units that are either available or not. Making it more versatile, by allowing it to function as conventional short-range artillery as well as a CS weapon makes it viable to deploy it with every tank unit, thus increasing the probability that some of them are in the right place at the right time.

If you've giving this street-fighting Centurion a smaller main gun with a higher elevation range, why not put a 20mm cannon next to it? That's another highly accurate weapon with limited side-effects which is useful in street-fighting: taking out the sniper on the top floor without killing the innocents cowering on the floor below, that sort of thing...

In most urban settings, 20mm can be as bad as large calibre HE round.  Afterall, the main function of a 20mm cannon is to use a HE round itself and a lot of splinters.   [/quote]

But you don't have to use HE: dual-feed cannon are common, so you could have solid APBC in one side and HE in the other. The 20mm barrel should be as long as possible, cross-braced to the main gun barrel in the same manner as the BMP-3's 30mm, and the weapon should have a single-shot capability. The idea is that it can switch between being a giant sniper rifle, A giant HMG or a small-calibre grenade launcher as you wish.

The Russians seem to think that 30mm cannons are the thing for urban warfare as their BMP-T demonstrates.

[rickshaw]

That is a possibility, however you still need to remove the stopper in the end of the case before loading, which of course slows the loading sequence.

That was what I meant by a well-designed ammo rack. Either:

a) the closure of the case is combustible and the rack provides a solid cover or shield for it when it's stowed,

b) the case has a solid stopper which engages with the rack when you stow it, so that when you pull it out, the stopper stays in the rack.

Commendable ideas.  You might be surprised to learn that well into the 1960s, tanks were still being designed with dry ammunition racks (AMX-30, Leopard I, T-55/T-62, M-48 are examples I'm aware of), despite the experiences of WWII still being relatively fresh.

The problem with (b) is that you're still left with bags falling out.  The powder bags aren't secured in the shell case, they're lose, which allows their rapid removal.  OK, that could be overcome by using cloth tapes or something similar but you're still left with a means of disposal for the spare powder bags.  With high ROF, they accumulate quickly, presenting a real danger in a tank turret.   You could, I suppose have a disposal chute which you could toss the bags in and have them drop out the bottom of the vehicle but then the battlefield would be littered with the things...

But you don't have to use HE: dual-feed cannon are common, so you could have solid APBC in one side and HE in the other. The 20mm barrel should be as long as possible, cross-braced to the main gun barrel in the same manner as the BMP-3's 30mm, and the weapon should have a single-shot capability. The idea is that it can switch between being a giant sniper rifle, A giant HMG or a small-calibre grenade launcher as you wish.

Remember we're talking about the late 1950s, early 1960s.  AIUI, dual feed auto-cannons didn't come into much use until a decade later.  I was limiting my thoughts to the period in question.  Sure, if you want to extend it further, then a dual feed weapon could do it but 20mm is, IMHO, a bit of an overkill.  A HMG is more than adequate.  It will penetrate most domestic and commercial walls and is just as deadly as a 20mm.  The only advantage the 20mm has that it can deliver a small HE round and relies primarily on splinters for effect whereas the .50cal uses a solid round.

Co-axially mating two weapons eases the gunner's job, it must be admitted but it invariably means a mount that doesn't let either weapon perform to it's strengths.  In my design, you have a demolition weapon which can be used to destroy buildings/obstacles and automatic weapons which can be used for suppressive fire and which can cover a larger arc than a single turret can.

The design I proposed used weapons already either in service in the British Army in late 1950 or readily available to it.

The Russians seem to think that 30mm cannons are the thing for urban warfare as their BMP-T demonstrates.

Well, let me just point out, the Russian Army has never really given much consideration to "hearts and minds" when fighting in any environment, so of course they'd be happy to use something as large as a 30mm cannon in urban fighting.

[crudebuteffective]

The conversations and ideas seems to have taken this thread full circle

Centurion prototype/mk 1 with 20mm polsten fitted because it was thought wasteful of ammo to use the 17pdr against soft targets