# A Better 6 pounder



## yulzari (Apr 22, 2012)

The 57mm 6 pounder anti tank gun/ tank gun was used widely by British, Commonwealth and US Forces in WW2.

Given the extraordinary lengths the British went to squeeze the 17 pounder into a tank turret could the 6 pounder have more performance squeezed out of it? 

A longer barrel to go with APDS like the Italian high velocity 60mm that went into the last operational Sherman gun tanks perhaps?


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## Shortround6 (Apr 22, 2012)

The British originally planed a 50 caliber barrel but a shortage of lathes with long enough beds force the production of the 43 caliber length barrels for a while. While a longer barrel would have squeezed out a bit more performance I believe the Italian/Israeli high velocity 60mm used an even bigger cartridge case to get it's performance. Possible in WW II but it also means fewer rounds per tank in the storage racks and a shorter barrel life.


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## tomo pauk (Apr 22, 2012)

The longer barrel can give only so much a performance growth. The Germans used different rounds for 'mid power' 7,5cm (L43/46/78; even the L46 using different round vs. other two?) vs. the 'hi-power' 7,5cm L70, the 8,8cm L56 and L71 were also firing different rounds, same for 5cm L42 and L60 - just to give some perspective.
Mounting the 6 pdr as-is into tanks in 1941-42 would give far more boost for UK Commonwealth tank forces, for AT work, let alone the 'soft' attack; not the topic here, though.


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## yulzari (Apr 23, 2012)

The advantage of retaining the 6 pounder is that it fitted the existing turrets and chassis. 

One can tweak the ammunition as well as the gun. With a longer barrel you will need to alter the burning charge and characteristics to maintain the projectile's acceleration down the extra barrel length. Not a great increase, but combined with APDS it makes it just that bit nearer 77mm penetration if not full 17 pounder penetration. A muzzle brake would mitigate greater forces on the existing mountings though the greater barrel weight would alter the balance of the gun.

So British and Commonwealth tanks can stay effective until the end of the war using 6 pounder tanks to support 75mm ROF tanks, much as 6 pounders were used in Italy and as Fireflies were to support Shermans in NW Europe. Saving all the effort into squeezing the 17 pounder into something. The 17 pounder needed to go into a 17 pounder tank and that was the Centurion, so skipping the Comet.


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## davebender (Apr 23, 2012)

Most army targets are soft targets. HE filler amount is mostly related to shell size. So I cannot see much point trying to give the 6 pounder cannon even more velocity. Britain would be further ahead using the 6 pounder as is and spending development money trying to build something similiar to the German 7.5cm Pak40.

The 17 pounder cannon is not the answer. It weighs twice as much as a Pak40 which made it a clumsy AT gun and it would not easily fit in a tank turret. Consequently the British army had to develop the 77mm HV cannon for their new Comet tank. Perhaps Britain could develop the 77mm HV cannon and skip the 17 pounder entirely.


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## Shortround6 (Apr 23, 2012)

The 17pdr had the performance of the 75mm/L70 in the Panther tank which put it in a rather different class than the Pak40. The Panther gun also weighed about twice as much as the 75mm/L43-46-48 series of guns. Perhaps the Germans should had skipped the 75mm/L70 ?


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## davebender (Apr 23, 2012)

Germany had priorities right. They developed the Pak40 first and it served as their main tank / AT / assault artillery cannon during 1942 to 1945. The Panther cannon was developed later and was never used as a towed AT gun.


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## Shortround6 (Apr 23, 2012)

First lets a fact or two straight. The 17pdr did not weigh twice what a Pak 40 did, it weighed about 50% more. It also weighed a whole lot less than than all the rest of the heavy AT guns the Germans dragged onto the battle field, like all those 88mm guns. Like the 75mm/L70 the 17pdr could out penetrate the 88mm/L56 at most normal combat ranges. 
The British 6pdr could have been looked at the Germans for a few hints also. When loaded with the same type of projectile as the PaK40 (APCBC) it wasn't that far behind in penetration.


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## yulzari (Apr 24, 2012)

My objective was to examine if British industry could have saved themselves the time and cost of trying to fit a 17 pounder into some modification of existing tanks by upgrading the 6 pounder as an anti tank weapon. As in Italy I would presume the majority of tanks would use the ROF 75mm as their principal job is to use HE to support infantry, retaining a proportion of (upgraded) 6 pounder tanks for protection.

Industry could then be devoting it's time and resources into a proper (ie Centurion) 17 pounder tank in full service for a year earlier and no need for the 77mm at all.


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## tomo pauk (Apr 24, 2012)

17 pdr was needed to reliably defeat the Panther and heavier stuff. British had one modification of the existing tank that cost them almost nothing, that being Sherman Firefly. It was feasible in 1943, too bad it was not present in far greater numbers from winter 1943/44, especially in Normandy. 
For something of lower power, the derivative of the 3in AAA cannon was a choice, materialized as the 77mm cannon. Unfortunately, it was too late, too few; one wonders if the Cromwell might have carried it?* With APDS, the 'animals' are within the scope.
Further down, the 75mm with APDS might be a nasty surprise for an unsuspecting Panther's or Tiger's crew. And one still gets good HE performance, with shell being of modest size (= more to be carried, vs. the bigger two). 
Sorry if it sounds like I'm raining into your parade, just think that Brits have had more tempting options, as far as tank armament is in question. The British tank development (for tanks used in ww2) received plenty of the bad rap. I can agree with much of it.

*will try to compare the layouts of Cromwell, T-34-76 T-34-85; the 77mm should need turret of the size in-between of the later two, or maybe as big as for T-34-76, if the muzzle brake is carried?


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## davebender (Apr 24, 2012)

> British had one modification of the existing tank that cost them almost nothing, that being Sherman Firefly.


Have you looked at the amount of craft work required to convert a Sherman tank into a Sherman Firefly? I am unable to find a historical price but I suspect the conversion cost as much as the original tank.


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## tomo pauk (Apr 24, 2012)

Yes, I did. 
Brits have deleted the hull gun, using the place now vacant (no hull gunner) for ammo stowage. The stowage box was relocated at the front of the hull, they welded the armored box for radio at the back of the turret, radio being accessed through the hole cut in the rear turret wall. The main modification was the new cannon, installation being simplified through usage of existing trunnions (of the 75mm cannon installation). 
Seems like a far simpler modification than Cromwell -> Challenger, of Churchill -> Black Prince. Hull remained the same (bar the 'patching' the hull, where the MG was), while the turret was a non-fancy modification of the one that was shipped from the USA.


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## Shortround6 (Apr 24, 2012)

Tanks and tank cannon ( and ammunition ) are a lot like aircraft. It take several years for a program to go from drawing board to service use. A good planner is never trying to match what his enemy just put into the field but what he thinks his enemy will put into the field in 2-3 years. The British spent several years behind the curve due to decisions made in 1937-40 and then stalled as they tried to make up for the losses in France. At some point they decided to get to the front of tank/anti-tank armament, instead of being in 3rd place, and stay there. Stopping the 17pdr to go ONLY with the 77mm would have dropped them back in the race. While APDS turned out to work very well, it was by no means a sure thing even in 1944 and the results of firing trials with bad batches of ammo and lack of accuracy with early ammo types only emphasize that relying on trick ammo instead of the developing bigger guns would have been foolish. 
Even the US with comparative lack of raw material supply problems was only getting enough APCR shot to it's tanks and tank destroyers with 3in/76mm in the fall/winter of 1944 to supply them with 2-5 rounds apiece at a time. This is a big hang up with the APCR 75mm for Shermans that is brought up so often. Every 75mm round with tungsten is one 76mm with tungsten NOT made. Which round is going to give the American tankers the best chance to take out a big German tank? 
A Low chance hit from the 75( even if better than the normal 75AP) or a higher chance hit from the 3in or 76mm guns?

Many of these tank, gun and ammo programs overlapped considerably in timing. 

Considering that the Germans fielded not only the 88mm DP guns, but dedicated 88 mm Anti-tank guns AND 128mm anti-tank and tank guns I don't see how the British can be faulted for fielding the 17pdr. 

The Germans may have done better to field the 75mm/L70 as an AT gun than trying to Feild those ultra heavy monsters.


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## tomo pauk (Apr 24, 2012)

I don't think that anyone is trying to blame the British for fielding the 17pdr. It took a while to come out with the suitable platform, though. A quote from T. Williams' site is quite telling (all quotes are from the expert):



> The Vickers 75mm HV was supposed to fit in the new Cromwell tank, but it was discovered rather late in the day that the Cromwell's turret was too small, causing a major crisis.



...the 75mm HV being a derivative of the AA 3in cannon, lined down to accept the US 75mm shells/projectiles. So Cromwell (as-is) is out of game :\
This is very interesting, about the cannon:


> The M61 [APCBC projectile]weighed 6.77 kg and was fired at 808 m/s from the Vickers HV for a muzzle energy of 2,200 kJ, compared with 620 m/s from the US tank guns (1,300 kJ). As a result, penetration went up from about 60mm to an estimated 87mm - not a huge amount more than the 6 pdr 7 cwt, but with a vastly more effective HE shell. The M48 [HE round] was downloaded to only 457 m/s since the thin-walled shell could not take the same high chamber pressures as the M61.
> (the 76mm M42 HE shell contained only 390g TNT compared with 667g for the 75mm M48)


...meaning the HE round was notably better for the 75mm HV. It was also better than of the 17pdr, HE round featured the thick-walled shell there. 17pdr is far better AP thing, unsurprisingly.
The 75mm HV was further modified into the 77mm:



> Meanwhile, Vickers persevered with their 75mm HV and the next tank, the Comet, was designed around it to make certain that it would fit this time! Before it could enter service, it was decided to take the calibre back up to the original 76.2mm so that the new gun could use the same projectiles as the 17 pdr, and the gun was then renamed the 77mm (presumably to distinguish it from the US 76mm).
> 
> the 77mm with this ammo [APDS] could penetrate 165mm [range not stated, 100 yds maybe?]



As for German AT guns heavier than the 'regular' 7,5cm pak, all of them were requiring the good vehicle to tow them. Going for the SP version makes far more sense to me.


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## yulzari (Apr 25, 2012)

The 77mm is a version of the Vickers 75mm HV that was intended to be the Cromwell's normal gun. Due to some **** up in coordination they then found it wouldn't fit! Hence the panic to try to get a 17 pounder into something. The Comet was designed around the 75mmHV that used the 3" AA case but reverted to the 3" (76.2mm) bore but was termed 77mm to avoid confusion with other 76mm rounds.

The external mantlet of the Sherman left less 17 pounder protruding into the turret than in a Cromwell/Churchill type of turret with an internal mantlet. Even then it had to be mounted on it's side and substantially modified. Put one in a Cromwell and the breech hits the turret rear if it fired. The good news is that it would have too little room left in the turret to load a 17 pounder round anyway.....

I heard a (very) dubious story that someone at the time asked if a 17 pounder could be put into a Grant as there was more room inside, the turret be removed and additional armour added.

The 17 pounder was a next generation tank gun and really demanded a next generation tank (Centurion). The 77mm,, nee 75mmHV, was the intended 1943/4 intermediate gun. In it's absence, and in the knowledge that a 6 pounder APDS was a viable (if not ideal) anti tank gun, I wondered if it could fill the gap with a little tweaking.

If the Vickers 75mmHV had fitted then the Cromwell (and presumably Churchill) would have been quite formidable machines in 1944.


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## Shortround6 (Apr 25, 2012)

tomo pauk said:


> I don't think that anyone is trying to blame the British for fielding the 17pdr.



It is not you but somebody on this thread is trying to make out like it was a mistake. 



tomo pauk said:


> As for German AT guns heavier than the 'regular' 7,5cm pak, all of them were requiring the good vehicle to tow them. Going for the SP version makes far more sense to me.



Very true, once you are above the size of the 50mm Pak or perhaps the 6pdr manhandling the guns any distance beyond a few hundred yds is impractical. However towed guns are cheap. A towed gun may cost 10% of what the similar gun in a tank would cost and trucks are no where near as expensive as any sort of track laying vehicle.


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## tomo pauk (Apr 25, 2012)

yulzari said:


> The 77mm is a version of the Vickers 75mm HV that was intended to be the Cromwell's normal gun. Due to some **** up in coordination they then found it wouldn't fit! Hence the panic to try to get a 17 pounder into something. The Comet was designed around the 75mmHV that used the 3" AA case but reverted to the 3" (76.2mm) bore but was termed 77mm to avoid confusion with other 76mm rounds.
> 
> The 17 pounder was a next generation tank gun and really demanded a next generation tank (Centurion). The 77mm,, nee 75mmHV, was the intended 1943/4 intermediate gun. In it's absence, and in the knowledge that a 6 pounder APDS was a viable (if not ideal) anti tank gun, I wondered if it could fill the gap with a little tweaking.
> 
> If the Vickers 75mmHV had fitted then the Cromwell (and presumably Churchill) would have been quite formidable machines in 1944.



Designing a whole new tank in order to properly* accept a modestly sized gun is really out of whack. 'Properly' meaning a rotating turret for the gun, 3 crew members in turret, coax with plenty of ammo, plenty of main gun ammo... 
Agreed on 75mm HV for Cromwell/Churchill, it would've given the Germans a good ride for their money. In lieu of that, the APDS for 75mm is again my favorite 



> The external mantlet of the Sherman left less 17 pounder protruding into the turret than in a Cromwell/Churchill type of turret with an internal mantlet. Even then it had to be mounted on it's side and substantially modified. Put one in a Cromwell and the breech hits the turret rear if it fired. The good news is that it would have too little room left in the turret to load a 17 pounder round anyway.....


Yep, the Comet/Cromwell look like having a gun 'inside' the tank, while the Sherman looks like the gun is 'outside' of the tank.


> I heard a (very) dubious story that someone at the time asked if a 17 pounder could be put into a Grant as there was more room inside, the turret be removed and additional armour added.


 
The Grant + 17 pdr (or even the US 76mm; all minus the 37mm turret) fits somewhere between StuG-IIIG and JagdPanther, a most tempting combination. 


Shortround6 said:


> It is not you but somebody on this thread is trying to make out like it was a mistake.


Roger that.



> Very true, once you are above the size of the 50mm Pak or perhaps the 6pdr manhandling the guns any distance beyond a few hundred yds is impractical. However towed guns are cheap. A towed gun may cost 10% of what the similar gun in a tank would cost and trucks are no where near as expensive as any sort of track laying vehicle.



The SP guns need far less crew to operate an ATG (and other artillery) efficiently vs. their towed counterparts. So a trade off between fewer manpower and more expensive hardware? At the time we arrive at 8,8cm PaK, let alone the 12,8cm (and their Soviet equivalents), the prime mover required for those is not cheap anymore. Maybe the 17pdr, 85mm D-44 and (unbuilt) 7,5cm L70 PaK would be the heaviest cannons able to be 'cheaply' towed, including off-road towing?
Sure enough, a truck-borne 7cm+ SP ATG would be interesting; Italians were experimenting with such a vehicle (along with SP AAA 90mm).


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## Shortround6 (Apr 25, 2012)

SP guns do need less crew but what is often over looked is that SP guns often had a lower rate of fire, a lower rate of engagement, in some cases limited traverse, and in most all cases except for the big German guns ( or AA guns), harder to hide. 

The loader on a towed gun stood, or knelt, by the breech and his job was to shove a shell into th breech whenever the gun fired and the breech opened itself. There was another crewman, or a chain of them, reaching to the ammo supply, who slapped a fresh shell into the hands of the loader. The SP gun loader had to get the rounds out of the rack/s, orientate them and then do the loading. The towed gun's gun captain could be a few yards to one side or the other of the gun for a better view, especially after the gun kicked up a cloud of dust or dirt. Perhaps the SP gun commander could dismount? This tactic was used by a few SP guns.
Again, in different circumstances, different weapon proved better than the other but often, not in all circumstances. 

And yes, when your towed guns start to get in the 5-10 class, their tow vehicles tend to get specialized and expensive.


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## tomo pauk (Apr 25, 2012)

Good post; the limited ability to hide/camouflage being maybe the major shortcoming of the SP vs. a towed variety. As for the kicked dust, the higher line of fire should make that a less of an incident for a SP variant, so the firing position is less likely to be revealed?

(yulzari, if you think the thread is going way off topic, just let me know and I'll reduce the non-6pdr posting)

I'd like to return to the 75mm ('plain', not HV) + APDS. 
For comparison sake, the penetration of the 77mm HV went up some 50% when firing APDS vs. the results of the APCBC. The APDS shot being 45% of the APCBC shot's weight. The penetration of the 6pdr grew similarly, APDS vs. APCBC. Under same token, the penetration of the 75mm gun, with APDS replacing the other AP shots should rise for 50%. Or perhaps only 40%, just to be on the safe side. The data found on the 'net suggest that 75mm was able (at 30 deg from normal) to pierce 58-75mm at 500m, and 45-70 mm at 1000m. 
Add 40%, and 85-110 mm can be defeated at 500m, 65-100mm at 1000m. All at 30 deg - the Panther is a fair game here. At 0 deg, penetration is at higher numbers of the interval - the Tiger's sides can be penetrated under 1000m, front under 500m. The quirk is that German drivers can drive the tank, terrain permitting, at 30-60 deg (plus 90/180/270 deg) vs. the gun that is about to fire at him. Well, better bring the 17pdr - now you know what a 'reliable penetration' menans 

About this:



> the 77mm with this ammo [APDS] could penetrate 165mm [range not stated, 100 yds maybe?]



It's 1000 yards


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## yulzari (Apr 25, 2012)

Going off topic is part of the charm of the forum but it would be nice if someone could contribute to the question of improving the 6 pounder rather than what they would prefer to have instead. I would prefer the 17 pounder but it wasn't going to fit anything in 1943/4 British production. 

The 6 pounder did fit and was a better AP gun than it's bored out 75mm companion using a WW1 French field gun case. In the Western Desert the AP shortfall of the Grant's American 75mm was known and they took captured German 75mm projectiles and fitted them into captured French 75mm cases. Now if the Grants had been captured too the whole thing would have been free. Yes I do know the great thing about the Grant was that it could take out antitank guns at range with HE.


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## Shortround6 (Apr 26, 2012)

The won't fit problem is due in part to mistakes made in 1938-1940 in tank-design and procurement. The Covenanter was a step backward and the Crusader was left playing catch up and barely got them back to where they were in 1938 (and that is being charitable) only with thicker armor. And so on.

Back to the question. How much improvement are you looking for? 

Mr. Williams has two photos on his web site of interest to use here. the page is ANTI

the 4th photo down GERMAN BRITISH WW2 TANK GUN AMMUNITION and the 14th photo MODERN SUB-CALIBRE AMMUNITION (2) 

The second shows the WW II 6pdr case next to the modern 60x410R (IMI / OTO 60mm) case. 

As a rough rule of thumb a 10% increase in velocity needs 20% more powder. 

Two guns used different length barrels _with the same ammunition_ is this velocity range. the 6pdr of course with lengths of 43 and 50 calibers ( be sure your source is comparing the same ammo) and the German 75mm/L43 and L48 tank guns. the difference in armor penetration between the barrel lengths percentage wise is in the low single digits, further lengthening of the barrels would bring diminishing returns, an additional 5-7 caliber in crease in length would yield a smaller increase in penetration. 

for "improving" the 6pdr (without changing the ammo type, like going to APCR or APDS) is going to require a bigger cartridge case. Can the existing barrel/chamber be bored out bigger or not? Can the existing Breechblock take the larger case (both in physical size and in strain) ? can the recoil mechanism handle the increased load or will it need to be modified? 
Too many modifications and you are working on a new gun and if you are working on a new gun you might as well work on a bigger one.


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## tomo pauk (Apr 26, 2012)

Think SR6 provided the implications about the extracting more penetration from the 6pdr.

I'll make an assesment about the needs capabilities of the W. Allied anti-tank 'machinery'.
In tracked form, they had the Sherman Firefly, Challenger, Avenger, Achiles, M4 (76), M-10/Wolverine, M-18, - all available for fighting in NE Europe in second half of 1944*. In towed 'flavour', there were 17pdr and 3in ATG. I've listed the 'tools' that were, more or less, able to penetrate Panther and heavier stuff. Sure enough, the Tiger II and Jagtiger would be somewhat safer than the lighter AFVs, but it looks to me that Germans were the ones that should be worried, not Allied tankers. 
What the W. Allies in that time frame were short of was the AFV that would shrug off at least the 7,5cm L48 hits with ease. 

One can wonder why the APDS projectile of the 17pdr was no adopted for the US 76mm, the performance would be as good as of 77mm HV (=165mm at 1000yds @ 30deg), and the modifications required far easier to pull off (changing the sight, instead of changing the main weapon; benefits: non-British/CW tankers can use it, too; the ammo count remains the same).
Sure enough, a JagdChurchill** (with 17pdr), or the JagdCromwell (at least 77mm HV, or US 76mm, or, hopefully, the 17pdr) sound great to me, once the fighting is out of the bocage country.


*with Comet arriving in late 1944
** a primitive version of that was produced in 1941, variant of the 3in AA gun being the weapon


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## Shortround6 (Apr 26, 2012)

The British did try something called the 8pdr which was supposed to fit into the 6pdr mounts and give a 28% increase in penetration using a 59 caliber length barrel using a 59mm bore (?). When the gun wouldn't balance in the mountings a shorter 48 caliber barrel was tried but performance fell off to little better than the 6pr, project canceled in Jan 1943.


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## tomo pauk (Apr 26, 2012)

Somewhat related to the topic, a penetration calculator. Take it for what is worth:

WWII Gun vrs Armour Calculator


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## yulzari (Apr 27, 2012)

You can make changes to the propellant within the same case but there are consequences.

A slightly longer burning propellant to keep the 'push' going up a longer barrel will raise breech pressure but British breech pressures were already higher than German ones. 

Reducing the depth of seating frees up a little more case capacity but there are consequences there too. 

The projectile can be worked on. A more accurate APDS would be a prime choice.

Can the recoil mechanism accommodate the extra performance or will it need upgrading? 

Certainly it would be a further mark of the 6 pounder but no great changes and will still fit.I would expect it to be a whole package of minor changes rather than one magic one. More is always better but a 20% improvement over penetration found in 1943 will tip the balance I would judge.

The key thing is it must fit existing turrets to the extent that it is a simple swap. that is the only reason for pursuing this goal.


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## Vincenzo (Apr 27, 2012)

Shortround6 said:


> First lets a fact or two straight. The 17pdr did not weigh twice what a Pak 40 did, it weighed about 50% more. It also weighed a whole lot less than than all the rest of the heavy AT guns the Germans dragged onto the battle field, like all those 88mm guns. Like the 75mm/L70 the 17pdr could out penetrate the 88mm/L56 at most normal combat ranges. .



i'm with dave for weight of 17 pdr, around 6400 lbs, 1800 lbs the gun and 4600 lbs the carriage. this is much less of 88 Flak 18/36 but this is for AA carriage of this. less but not so much comparating to pak 43. On paper has good advantage of penetration with same ammo v/s the flak 18/36 thanks to higher MV.


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## tomo pauk (Apr 27, 2012)

From the UK AT guns book, Osprey New Vanguard, about the 17pdr:



> Weight of gun and carriage: 2 tons 17cwt 1qr 251b or 6,5371b



It was really asking for SP version, from the Straussler conversion further.


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## Shortround6 (Apr 27, 2012)

There are a number of sources that give a weight of 4600-4700lbs "in action". 

There may be a different definition for " weight of equipment". 

A few books may have misprints or typos. 

The Americans managed to build a few 90mm guns on a two wheel carriage at the end of the war, the T8 gun on the T5E2 carriage ( twice lightened from the T5) for 6800lbs with a 2290lb gun and breech. 

The standard US 3 in AT gun went about 4870lbs with it's WW I style barrel and cobbled together 105 howitzer carriage.

But we all know the British couldn't possibly design and build weapons to rival the Germans


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## tomo pauk (Apr 27, 2012)

The 'Anti tank weapons' by Chamberlain Gander gives 2,9 tons as 'in action' weight of the 17pdr.



> But we all know the British couldn't possibly design and build weapons to rival the Germans



Under 160mm, Russian hardware please


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## Juha (Apr 27, 2012)

British should only have been far-sighted and should have ordered some Vickers Model 1931 AA guns for themselves before the war as interim AA gun before 3.7" AA gun was ready. In Finnish army our version, 76 ItK/34 V, Vickers got later 76 psa Vj4 armour piercing tracer (AP-T), the projectile weight 6.5 kg and it had muzzle velocity of 750 - 790 m/sec. Rumanian 75mm version also had AP ammo and it was used in A/T tasks few times.

Juha


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## Shortround6 (Apr 28, 2012)

The problem with using some of these AA guns, even just the barrels and breeches with new recoil mechanisms and carriages is that metallurgy was making big strides during the 20s and 30s. WW I and 1920s designs had rather heavy barrels compared to some WW II guns. Compare the US 3in tank and anti-tank gun with the 76mm gun. Despite using a working pressure 25% higher the 76mm barrel is hundreds of pounds lighter. The US 3 in is a WW I coast defense/AA gun. 

Using AA guns for AT work is a sign of desperation and/or things have really dropped in the pot. Troops at the front will use what they have and DP or even "triple threat guns" look good to the people at home ( and to politicians) in propaganda pieces but using AA guns to shoot tanks is a waste of resources.


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## Shortround6 (Apr 28, 2012)

tomo pauk said:


> The 'Anti tank weapons' by Chamberlain Gander gives 2,9 tons as 'in action' weight of the 17pdr.



I will agree that the 17pdr went 3 tons or so. Perhaps the version on the 25pdr carriage is were the lower weight comes from? 

The 17pdr could do at 900 meters what the Pak 40 could do at 100 meters using similar projectiles though.


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## Njaco (Apr 28, 2012)

> Using AA guns for AT work is a sign of desperation and/or things have really dropped in the pot. Troops at the front will use what they have and DP or even "triple threat guns" look good to the people at home ( and to politicians) in propaganda pieces but using AA guns to shoot tanks is a waste of resources.



But isn't that exactly how the German 88 became famous?


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## Shortround6 (Apr 28, 2012)

It became famous but it really wasn't a good use of resources. 

For instance while some of Rommel's 88s were shooting up all those British tanks, British bombers were pounding the crap out of his supply ports. 

AA guns in forward AT positions are not tied into the AA net and are not connected to the AA predictor/director which means they are very ineffective AA guns even at defending the front from air attack not to mention the fact that if they at aircraft before the attack comes they revel their position to artillery spotters. 

The AA carriage is much heavier (2-3 times) what an AT carriage weighs and much more costly, it requires a bigger tow vehicle. It takes more time to em-place and camouflage.

The 88 gained fame when the Germans had few good 75mm AT guns available and it was the 88 or 37mms in France and the 88 or 50mms in North Africa and Russia. Once it had the reputation it kept it and the later bigger 88s added to it but using the full AA guns had never been a really good idea.


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## Juha (Apr 28, 2012)

Shortround6 said:


> The problem with using some of these AA guns, even just the barrels and breeches with new recoil mechanisms and carriages is that metallurgy was making big strides during the 20s and 30s. WW I and 1920s designs had rather heavy barrels compared to some WW II guns. Compare the US 3in tank and anti-tank gun with the 76mm gun. Despite using a working pressure 25% higher the 76mm barrel is hundreds of pounds lighter. The US 3 in is a WW I coast defense/AA gun.
> 
> Using AA guns for AT work is a sign of desperation and/or things have really dropped in the pot. Troops at the front will use what they have and DP or even "triple threat guns" look good to the people at home ( and to politicians) in propaganda pieces but using AA guns to shoot tanks is a waste of resources.



Vickers gun was very early 30s design, and what I was thinking is an A/T vehicle like Archer or German Marders, so ritish would have had heavy SP A/T gun capable to easily knock out Mk IIIs and IVs which also had capability to knock out A/T guns with a good HE round.

Also it might have been used as a basis of heavy tank gun like Germans used their 88 Flak gun for theit 88mm tank gun
Juha


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## Vincenzo (Apr 28, 2012)

Shortround6 said:


> I will agree that the 17pdr went 3 tons or so. Perhaps the version on the 25pdr carriage is were the lower weight comes from?



i think from people that not understand difference from carriage weight and weapon weight. the 25 pdr carriage weight around 4000 lbs with 17 pdr gun are almost 5800 lbs (just taking no modification).


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## Shortround6 (Apr 29, 2012)

The _complete_ 25pdr gun went 3968lbs. the barrel and breech went 1000lbs. SO a 25pdr carriage _without_ barrel and breech would be under 3000lbs( 2968lbs?) 

A 17pdr barrel and breech was 1822lbs. So 2958lbs + 1822lbs = 4790lbs ?

17pdr carriage with split trails and 60 degree traverse being much heavier than the 25pdr carriage.


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## DonL (Apr 30, 2012)

I also agree that something similar ton the 7,5cm Pak 40 would be the best.

From weight and performance the Pak 40 is near in it's own class.

6 Pounder: weight 1140kg; performance: [email protected]; 500m (APCBC)
7,5cm Pak40: weight 1425; performance: [email protected]; 500m (APCBC)
17 pounder: weight 3050kg; performance: [email protected]; 500m (APCBC)

The 7,5cm Pak 40 had 25% more weight then the 6 pounder, but 35% more performance.
The 17 pounder had 100% more weight then the Pak 40, but only 29% more performance.



> First lets a fact or two straight. The 17pdr did not weigh twice what a Pak 40 did, it weighed about 50% more. It also weighed a whole lot less than than all the rest of the heavy AT guns the Germans dragged onto the battle field, like all those 88mm guns. Like the 75mm/L70 the 17pdr could out penetrate the 88mm/L56 at most normal combat ranges.
> The British 6pdr could have been looked at the Germans for a few hints also. When loaded with the same type of projectile as the PaK40 (APCBC) it wasn't that far behind in penetration.



This coment is also not objektive.


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## Jabberwocky (May 1, 2012)

17 pounder had an in-action weight of 4,624 lbs, at least according to the Royal Artillery. That's just under 50% more than the Pak40 7.5 cm, which had an in-action weight of about 3,135 lbs.

As for the HV 77 mm coming before the 17 pounder, that's putting the cart before the horse. The 77mm was basically just a cut-down 17 pounder, fitted with the shorter breech from the Vickers-Armstrong 75mm HV project and less powerful ammunition from the 3-inch 20cwt. It was developed precisely because the original weapon was slightly too large to fit British tanks (as was the Vickers-Armstrong high velocity 75mm L/50 gun)

The problem with fitting the 17 pounder into UK manufactured tanks is that UK tanks had turret rings that were too narrow, primarily due to the narrow UK rail gauge and the loading gauge (and thus the width of rail tunnels). The UK War Office change the loading gauge design limitation from 8'9" to 9'6" in 1941 (to accommodate the Churchill) and then dropped the requirement altogether in 1942.

The Sherman, which they managed to just about shoehorn a 17 pounder into (after a pretty significant redesign, including redesigns of the barrel and recoil system), had a 69" turret ring. In comparison, UK tanks had the following turret ring widths:

Matilda II: 54.25 in
Churchill: 54.25 in
Valentine: 57.7 in
Cromwell: 57.2, later 64 in
Comet: 64 in
Challenger: 70 in


The QF 6 pounder (or more accurately its ammunition) was developed significantly and the gun remained a useful AT weapon even against targets in the 45+ ton category to the end of the war. APCR (first issued in late 1943) was credited with 100 mm at 1000 yards/30 degrees from the Mk 4 (L/50). APDS, issued in mid-1944, was capable of 140 mm + at 1000/30, although accuracy was not good, due to variable separation of the sabot. The problem was not as pronounced as in the 17 pounder though.

The gun remained in service with UK and US anti-tank detachments all the way through to the end of the war. 

The main problem with the QF 6 pounder is the lack of effective HE, which was more a doctrine issue (in the UK) than an design issue. I believe (but I could be way out on this one) that HE ammunition was first issued for UK guns in March or May 1944, but ammunition was in relatively short supply. HE was used in late 1944 and through 1945 by 6 and 17 pounders for bunker/ hardened emplacement plinking at long-ranges, outside of MG ranges.


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## Jabberwocky (May 1, 2012)

17 pounder had an in-action weight of 4,624 lbs, at least according to the Royal Artillery. That's just under 50% more than the Pak40 7.5 cm, which had an in-action weight of about 3,135 lbs.

As for the HV 77 mm coming before the 17 pounder, that's putting the cart before the horse. The 77mm was basically just a cut-down 17 pounder, fitted with the shorter breech from the Vickers-Armstrong 75mm HV project and less powerful ammunition from the 3-inch 20cwt. It was developed precisely because the original weapon was slightly too large to fit British tanks (as was the Vickers-Armstrong high velocity 75mm L/50 gun)

The problem with fitting the 17 pounder into UK manufactured tanks is that UK tanks had turret rings that were too narrow, primarily due to the narrow UK rail gauge and the loading gauge (and thus the width of rail tunnels). The UK War Office change the loading gauge design limitation from 8'9" to 9'6" in 1941 (to accommodate the Churchill) and then dropped the requirement altogether in 1942.

The Sherman, which they managed to just about shoehorn a 17 pounder into (after a pretty significant redesign, including redesigns of the barrel and recoil system), had a 69" turret ring. In comparison, UK tanks had the following turret ring widths:

Matilda II: 54.25 in
Churchill: 54.25 in
Valentine: 57.7 in
Cromwell: 57.2, later 64 in
Comet: 64 in
Challenger: 70 in


The QF 6 pounder (or more accurately its ammunition) was developed significantly and the gun remained a useful AT weapon even against targets in the 45+ ton category to the end of the war. APCR (first issued in late 1943) was credited with 100 mm at 1000 yards/30 degrees from the Mk 4 (L/50). APDS, issued in mid-1944, was capable of 140 mm + at 1000/30, although accuracy was not good, due to variable separation of the sabot. The problem was not as pronounced as in the 17 pounder though.

The gun remained in service with UK and US anti-tank detachments all the way through to the end of the war. 

The main problem with the QF 6 pounder is the lack of effective HE, which was more a doctrine issue (in the UK) than an design issue. I believe (but I could be way out on this one) that HE ammunition was first issued for UK guns in March or May 1944, but ammunition was in relatively short supply. HE was used in late 1944 and through 1945 by 6 and 17 pounders for bunker/ hardened emplacement plinking at long-ranges, outside of MG ranges.


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## yulzari (May 1, 2012)

The tank 6 pounder was always expected to support infantry with HE but the effectiveness of HE is a function of the size of the HE charge which is itself a function of the size of the projectile, thus a larger bore gives a better HE result. Artillery had established before WW1 that 75mm was really the lower worthwhile limit (though horse drawn field guns and mountain guns needed low weights so were often smaller). Hence we saw the efforts in the Mediterranean to fit surplus Sherman 75mm guns into Churchills as the doctrine was that infantry support with HE was the prime role of tanks.

The telling thing is that they retained a proportion of 6 pounders to cope with enemy armour. My hypothesis is that it would only take a small improvement in the anti armour capacity of the 6 pounder for it to do the same in NW Europe, save building Challengers and Fireflies and concentrate on progressing the full 17 pounder tank design into service before the end of 1944.


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## tomo pauk (May 1, 2012)

The APDS shot made the 6pdr as capable as feasible, before going into a '6pdr on steroids'? I still maintain that, in second half of 1944, W. Allies have had plenty of 'horizontal' solutions for Panther and heavier; an APDS shot for the US 76mm/3in makes the vehicles equipped as capable for the AT work as the 77mm HV. The '6pdr on steroids' still lacks HE punch, compared with 75mm and heavier, so the British still need a decent HE thrower to deal with targets more numerous than tanks/AFVs.



> My hypothesis is that it would only take a small improvement in the anti armour capacity of the 6 pounder for it to do the same in NW Europe, save building Challengers and Fireflies and concentrate on progressing the full 17 pounder tank design into service before the end of 1944.



Doest that mean that Challenger Firefly were not to be designed/built?

Hi, Jabberwocky,



> 17 pounder had an in-action weight of 4,624 lbs, at least according to the Royal Artillery. That's just under 50% more than the Pak40 7.5 cm, which had an in-action weight of about 3,135 lbs.



Would that be with the carriage of the 25pdr, or with split carriage? If it would not be much of a trouble for you, perhaps you could direct me towards an easily obtainable source that gives the figure; the 3 books I've have all state the weight in cation at circa 6400 lbs.



> The problem with fitting the 17 pounder into UK manufactured tanks is that UK tanks had turret rings that were too narrow, primarily due to the narrow UK rail gauge and the loading gauge (and thus the width of rail tunnels). The UK War Office change the loading gauge design limitation from 8'9" to 9'6" in 1941 (to accommodate the Churchill) and then dropped the requirement altogether in 1942.



It was too unfortunate that, after Matilda II, no British ww2 tank (worth speaking of) was not featuring sponsons.



> The main problem with the QF 6 pounder is the lack of effective HE, which was more a doctrine issue (in the UK) than an design issue. I believe (but I could be way out on this one) that HE ammunition was first issued for UK guns in March or May 1944, but ammunition was in relatively short supply. HE was used in late 1944 and through 1945 by 6 and 17 pounders for bunker/ hardened emplacement plinking at long-ranges, outside of MG ranges.



Perhaps you could kindly shed some light at the question: why the HE shells were not issued to the guns prior 1944?


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## Shortround6 (May 1, 2012)

The 6pdr went from (roughly) 74mm of penetration at 500yds/30^ to 84-88mm of penetration by going from the interim 43 caliber caliber barrel to the originally planned 50 caliber barrel and changing from APC to ABCBC shot. this later shot improved things even more at longer ranges as it was more streamlined and keep it's velocity better. British ammo was loaded to pretty high pressures to begin with so not much scope is left there. 
The British should have gotten the stick out and made a tank to use the 77mm or whatever you want to call it earlier. It used a hot loaded 3in AA case so the case and chamber were no great mystery. Just chamber up a modern barrel with enough chamber wall. pick your projectiles (75mm or 76.2 mm) and go to it. Futzing about with a "super" 6pdr is just going to delay the inevitable, a proper 75-77mm weapon.


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## tomo pauk (May 1, 2012)

> Futzing about with a "super" 6pdr is just going to delay the inevitable, a proper 75-77mm weapon.



That wraps it up.


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## yulzari (May 1, 2012)

But the 'proper 75mm-77mm' was half a failure to fit the Cromwell and half a failure to get it into service with Comet except just in the last few weeks in small numbers. 

By skipping this stage, when it was found impossible to use the 75mmHV in time in 1942, the real 17 pounder vehicle might have been in service in numbers in late 1944 while the 6 pounder held the fort in the meantime.. 

If we go back to 1941 and ensure the Cromwell would take the 75mmHV well and good; but my starting point is what action to take when it was found that the 75mmHV would not fit the Cromwell and that was too late to enlarge the turret. 

Not how to get the 17 pounder 77mm in tank service for D day. That is easy. Just wave a wand and say that the Ministry of Defence ordered such a weapon and tank in 1936. Job done. There was no novel technology in the Comet bar the APDS. The Centuar and Cavalier worked with Liberty engines. There were a variety of workable gearbox types to use and insisting on welding armour would have been easier as there was less competition then for the supply of suitable welding kit.

The various suggestions that the 17 pounder and/or 77mm should have been used earlier is perhaps somewhat like responding to a question of whether the RAF should have had just more Spitfires instead of maintaining Hurricane production for the Battle of Britain by saying they should have got the Typhoon in service in 1939. The Hurricane was already showing obsolescence in 1940 but it was useable and existed.Yes the Typhoon was far better and the desired replacement but it was not possible to produce it for 1940. The 6 pounder is the Hurricane equivalent. Good enough but not good. It existed in quantity. The 77mm is the Hurricane MkII/IV. Not the best, just a bit better and built only because the replacement had problems. This is an analogy and like all analogies, they are to illustrate a point and attacking the analogy does not destroy the original premise.

Now if someone can convince me that the 6 pounder was _unable_ to take on the task (and, yes, if i were the tankie I would want a 17 pounder or at least a 77mmHV) then I _would_ conclude my hypothesis was incorrect.

For the unwary, the 3" AA gun itself was far too heavy too large and could not take 77mm pressures as I am sure Shortround6 would be happy to confirm.


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## Juha (May 1, 2012)

yulzari said:


> Now if someone can convince me that the 6 pounder was _unable_ to take on the task (and, yes, if i were the tankie I would want a 17 pounder or at least a 77mmHV) then I _would_ conclude my hypothesis was incorrect.



If you read the history of 6th Guard Tank Brigade, you would find out that men of the brigade thought that 6pdr even with APDS wasn't adequate against frontal armour of Panther/Jagdpanther



yulzari said:


> For the unwary, the 3" AA gun itself was far too heavy too large and could not take 77mm pressures as I am sure Shortround6 would be happy to confirm.



As I wrote 75mm/76.2mm Vickers Model 1931 AA gun would have given almost as good penetration power as the German 7,5cm Pak 40 plus ability to fire reasonable good HE early in the war, it would not have been reliable Tiger killer frontally, but that would have been a problem only from Nov 42 onward. And as SP A/T gun like Archer or German Marder,so not as a tank gun, but something on tracks with long range killing ability against panzers and Paks.

Juha


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## Shortround6 (May 1, 2012)

yulzari said:


> But the 'proper 75mm-77mm' was half a failure to fit the Cromwell and half a failure to get it into service with Comet except just in the last few weeks in small numbers.
> 
> By skipping this stage, when it was found impossible to use the 75mmHV in time in 1942, the real 17 pounder vehicle might have been in service in numbers in late 1944 while the 6 pounder held the fort in the meantime..
> 
> ...



The question is how do you improve on the existing 6pdr to meet your goal, which you have haven't specified unless I missed it. what are you looking for 92mm penetration at 500yds/30 degrees or 100mm or 110mm?

The 6pdr was designed with the 50 cal length barrel and only made with the 43 cal barrel as production expedient due to a shortage of lathes to make the longer barrels. Increasing the length to 55 calibers or longer is going to give very little return without changing the powder charge. The 6 pdr was already operating at the top of the range of chamber pressures. If they could have used a different propellant that gave a higher velocity they probably would have. The Navy was able to use different propellants that gave longer barrel life because they gave the about the same pressures with a lower flame temperature but they rarely, if ever, increased the velocity.

This pretty much leaves reaming out the chamber to take a larger cartridge case with more volume and a larger charge to generate more gas at the same peak pressure. Now we are back to trying to figure out if the new case will fit the old barrel or will the chamber walls be too thin, will the new case fit the breech block. Will the breech block take the strain. as an example changing from a 90mm diameter case to a 100 mm diameter case increases the forces acting on the breech block by over 23% even at the same chamber pressure. Maybe the answer to all these questions is "_no problem_" and it is an easy change, but if the answer starts coming back as bulged barrels, or breech blocks setting back or other problems then what?


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## Shortround6 (May 2, 2012)

Juha said:


> As I wrote 75mm/76.2mm Vickers Model 1931 AA gun would have given almost as good penetration power as the German 7,5cm Pak 40 plus ability to fire reasonable good HE early in the war, it would not have been reliable Tiger killer frontally, but that would have been a problem only from Nov 42 onward. And as SP A/T gun like Archer or German Marder,so not as a tank gun, but something on tracks with long range killing ability against panzers and Paks.
> 
> Juha



The 75mm/76.2mm Vickers Model 1931 AA was not that great an improvement on the 3in 20cwt gun if the Wiki figures are to be believed. 2500fps with a 14lb shell? the old 3in 20cwt gun could manage 2040fps with a 17.5lb shell and up to 2500fps with a 12.5lb shell. increasing shell weight by 12% while keeping the same velocity is nice but not exactly a major leap forward.


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## Juha (May 2, 2012)

Shortround6 said:


> The 75mm/76.2mm Vickers Model 1931 AA was not that great an improvement on the 3in 20cwt gun if the Wiki figures are to be believed. 2500fps with a 14lb shell? the old 3in 20cwt gun could manage 2040fps with a 17.5lb shell and up to 2500fps with a 12.5lb shell. increasing shell weight by 12% while keeping the same velocity is nice but not exactly a major leap forward.



Yes, but Model 1931 was significantly lighter, 3,325/2,825kg, the later is in action weight, 3in 20cwt weighted 5,99 tons according to wiki.

Juha


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## fastmongrel (May 2, 2012)

I think the only way your going to get bigger guns in British tanks earlier is if you specify that all interwar and therefore early war tanks had to carry the WWI Hotchkiss type (40 cal I think?) 6 pounder. This would force British designers to use larger turret rings from the start as the Hotchkiss 6 pounder is a good sized lump. Going to the much smaller 47mm 3 pounder then the slightly smaller again 2 pounder allowed small turret rings to be used.


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## Jabberwocky (May 3, 2012)

tomo pauk said:


> Hi, Jabberwocky,
> 
> Would that be with the carriage of the 25pdr, or with split carriage? If it would not be much of a trouble for you, perhaps you could direct me towards an easily obtainable source that gives the figure; the 3 books I've have all state the weight in cation at circa 6400 lbs.


 
That's from the 1943 QF 17-pr handbook with the Mk I (split-trail) carriage. There is also a figure of 2 tons 17cwt 1qr 25lbs in the handbook - which equals 6540 lbs - as travel weight, but it doesn't specify what type of carriage. 

Most confusing. There seems to be some contradiction in both the handbooks and specialist literature. I have weights of the gun in action ranging from 4,001 lbs (!) all the way up to 6600 lbs in various books, with travel weights as high as 6900 lbs. 

Zaloga's US anti-tank artillery book also gives the 4624 lbs figure when comparing the 17 pdr with the US 3 inch. 
Delf's book on UK anti-tank artillery gives the weight as 6537 lbs, but then clouds the issue 
by referring to the weight of the gun as "over 4,000lb" when referring to crews moving it.

One of the other problems is that the British made a number of modifications to the carriage, adding more armour and substantially adjusting the recoil mechanism. There were at least three different 'Mk I' carriages, as well as a Mk Iw.

I'll do some more digging, but I'm beginning to wonder if the lower end figures aren't for the gun/carriage as is, while the upper weights are for the gun, carriage, spares and possibly ammunition. Maybe AVIA 46/187 or the later 17-pdr handbooks can clear this up.


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## tomo pauk (May 3, 2012)

Much appreciated, I'm hoping that the matter will be cleared 

Brits have found the way to mount a turret featuring the 20pdr cannon (84 mm L.64) at the Cromwell hulls, creating the Charioteer TD. Price paid was that turret was bulkier and of thinner armor. Looking at the pictures, the 20pdr, due to higher line of fire, recoiled into the space that, in Cromwell's turret, was occupied be the radio set. The mantlet was somewhat in the front, at least it seems to me by looking at the pics. So I'd say they circumvented the narrow hull ring limitation. 
Too bad that they did not mounted the 75mm HV, or 77mm HV into the Cromwell, using the outer mantlet and/or higher line of fire. Ditto for Comet/17pdr. The price would be the weight gain (for same protection level), no doubt about that.


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## Juha (May 4, 2012)

Ah
Charioteer mentioned, have ridden on one during a military exercise looong time ago, not the one in the attachment.

Juha


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## tomo pauk (May 5, 2012)

Great; my only 1st hand experience with 'tanks' was anti-tank drill vs. and ZSU-57 playing a tank (turret covered with canvas for the occasion), and I've been several times within the turret of the M-47 (48?) Patton. US-made tanks were being mothballed at the barracks I was serving 1990/91, Ljubljana - Slovenia.

How well the Charioteer was regarded in the Finish army?


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## Juha (May 5, 2012)

Now what I remember
it was fast and the gunner's sight was very good but the commander was fairly blind when buttoned up. The Finnish Charioteers had a mg, it was the type as used in T-34s IIRC. The cannon was very good. IIRC Army wasn't altogether satisfied because of light armour of the turret and because of the limited observation possibilities for the commander.

Juha


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## Juha (May 5, 2012)

My experience was also after we had "stopped" a tank attack during an exercise, after that we got a couple km ride on one Charioteer on road and off-road. Later I spent some time in the turret of one, which was camo'd in an A/T position for possible war use, at that time I noticed how good the gunner's sight was. And in 60s and 70s one could freely climb into the turrets of Pz IV, T-28, KV-1 etc at Parola Tank Museum.
Juha

And the Charioteer at Parola


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## Shortround6 (May 6, 2012)

Thank you for the pictures. They also show a few considerations of turret design. The Comet shows how elevation limits can affect turret ring size. At high angles of elevation the gun needs room to recoil ( and needs room behind it to load) and also look at the roof line. At large angles of depression the gun still needs room to recoil and be loaded. The range of elevation of the Comet was from +20 degrees to -10 degrees. The Charioteer had an elevation range of +12 degrees to -5 degrees even with the larger turret.


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## Juha (May 6, 2012)

Shortround6 said:


> Thank you for the pictures. They also show a few considerations of turret design. The Comet shows how elevation limits can affect turret ring size. At high angles of elevation the gun needs room to recoil ( and needs room behind it to load) and also look at the roof line. At large angles of depression the gun still needs room to recoil and be loaded. The range of elevation of the Comet was from +20 degrees to -10 degrees. The Charioteer had an elevation range of +12 degrees to -5 degrees even with the larger turret.


 
Yes, Charioteer wasn't perfect, IMHO not even optimal solution, but definitely more effective A/T system in 50s than Cromwell, and British (and Finns) needed A/T system that was effective frontally against T-54s/T-55s, so IMHO some failings were acceptable if the main point, mobile hard-hitting A/T system could be produced fairly cheaply and fast. In certain respects Charioteer was a bit like M-18 Hellcat.

Juha

BTW, I made a mistake earlier, in Charioteer commander was also gunner and the other man in the turret was loader/radio operator.


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## tomo pauk (May 6, 2012)

Charioteer is to the Cromwell what is the M-36 to the M4s. What was the disposition of the rest of the crew in the Charioteer?


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## Juha (May 6, 2012)

In principle it had a 3 men crew and the 3rd one was the driver, but because of the high muzzle pressure dirt made the observation of hits difficult when target was under 1500m away, so sometimes 4th man was carried in the place of Cromwell's hull gunner, he when readied for action would have moved to commander/gunner seat allowing the commander to move out of tank and 10-30m sideways, so that he would have been able to observe the fall of the shot and give if necessary corrections to the acting gunner/4th man.

Juha


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